CH turning on by itself problem

[mcm]

was asked about a central heating problem the other day but as not done much of this was not sure.

I was told that the central heating would come on by itself even if the programmer was switched to the off position. The heating would come on in the night on its own but on the programmer says its off, the timer works ok on the programer as tested the the on off times, was thinking it could be the valve sticking does this sound right?

The programmer is a drayton tempus six

 

[invisable]

is the boiler located where it can get cold does it have a froststat or a pipe stat installed ? (it could have a internal frost stat on the boiler).
sound like the boiler is coming on at night when the temperature drops to stop pipes freezing.

 

[i=p/u]

sounds good to me, cause this overides ..... but not to clued up either

 

[mcm]

is the boiler located where it can get cold does it have a froststat or a pipe stat installed ? (it could have a internal frost stat on the boiler).
sound like the boiler is coming on at night when the temperature drops to stop pipes freezing.

no the boiler is in the kitchen would'nt of thought it would get that cold. someone said about the valve could be sticking that at night it was moving causing it to come on. think its more than the programmer at fault but not sure.

 

[invisable]

What type of system is it does it have 2 valves (s plan) or one valve (y plan) the vavle could be sticking usally when a valve sticks it would just stay open or closed to let the heat through eg. heating would get hot when hot water is callling.

 

[UNG]

What make is the boiler. A lot of boilers have built in frost protection that activates when the temperature drops it normally kicks the pump in first at around 5° or 6° C and fires the boiler at 2° C

 

[mechelec]

Has the system got a room stat that is incorrectly wired ie in parallel with the programmer and has just been turned down low.
It could be the programmer that has a sticking relay and not switching off, but usually they fail open circuit not short.
Not sure how a sticking valve would cause the boiler to fire.

 

[chris murphy]

What make is the boiler. A lot of boilers have built in frost protection that activates when the temperature drops it normally kicks the pump in first at around 5° or 6° C and fires the boiler at 2° C

"Hello mcm",

I am a Heating Engineer - What UNG stated here could be the case - If the Boiler Frost Protection is operating the Heating should NOT actually run / Heat Up to `Normal` / Hot Temperatures - but the Boiler would Fire Up and the Pump should run and distribute a small amount of Heat around the System - then the Boiler would Go Off until the Frost Protection turned it on again If the Temperature within the Boiler dropped to actuate the Frost Thermostat.



I have noted outside Temperatures here in the London Suburbs of as Low as Minus 6 Degrees C during the early part of this Week - and Boiler Frost Protection turns on the Boiler at a Higher Temperature than this - usually approximately as UNG stated, there have also been some quite Cold Nights earlier in the Month.

Remember that the Cold Air is entering into the Boiler via the Flue - both the Air Intake and the Combustion Products exit - any Wind in the direction of the Boiler Flue will cause this to be more prevalent - Temperatures of much less Cold than I mentioned should actuate the Boiler Frost Protection.

The People in the Home would obviously be thinking that the Heating is `On` - But the Boiler Frost Protection should not actually Heat Up the Home - just Protect the Boiler from Freezing.

Perhaps the Heating is On during the Day normally - or this situation might have occurred during Cold Days also.

If the Members of the Household are out all Day and the Frost Protection had operated during a Cold Day it would usually Not be detectable because not enough Heat should have circulated around the Heating System for anyone coming in to notice.

But It is very likely that People who are Out all Day will have the Heating Set to come On a couple of Hours before they get Home - so they would definitely NOT know whether the Boiler Frost Protection had operated during the Day.

I can only suggest that on a Cold Night someone stays up and actually `Witnesses` the Boiler Fire Up - it should not run for a Long Period - after which it will Turn Off again - this is how the Boiler Frost Protection works.

BUT If the Heating System gets Hot - as normal it would be unlikely to be the Frost Protection - unless that is not Turning Off when it should after Warming the Boiler - then there is a Problem somewhere else.


Chris

 

[mcm]

hi chris

they said the heating was coming on during the night and it was very warm.

like i described I set the times on the programmer to see if they come on and off as they should and it does. Do you think as its getting warm when its ment to be off that it could be a faulty programmer? they say when it comes on in the night the programmer shows it being off any thoughts.

thanks

 

[chris murphy]

hi chris

they said the heating was coming on during the night and it was very warm.

like i described I set the times on the programmer to see if they come on and off as they should and it does. Do you think as its getting warm when its ment to be off that it could be a faulty programmer? they say when it comes on in the night the programmer shows it being off any thoughts.

thanks

"Hello mcm",

I have never come across a Programmer that caused this to happen - in the last 40 Years that I have been a Heating Installer / Engineer.

Especially as You mentioned that when the Boiler / Heating is On the Programmer shows that it is Off - But I would be interested to see if any of the Electrical Professionals on here do know whether this could ever happen regarding an `Internal Malfunction` of the Programmer - ?

When this happens do You happen to know whether the People in the Home decide to Turn Off the Boiler ? - How have they said that the Heating goes Off - Or does it then continue when the Programmer Setting comes to the Morning `On` Time ?


THIS is very unlikely But:


I am wondering if the Boiler Frost Protection Thermostat is Turning On the Boiler and instead of allowing it to just Fire for a short period of time to `Warm` the Boiler [and as a result of that the surrounding Pipework] - it is not Turning Off the Boiler after a small rise in the Temperature but is allowing it to run for a much longer period of time - ?

That would be a Very Strange situation because at what point would the Frost Protection Thermostat then `Turn Off` the Boiler ?

IF the situation with the Heating Turning On is caused by the Boiler Frost Protection Thermostat and the Boiler is then continuing to Run into the Morning `On` Period as determined by the Programmer because the Frost Thermostat is NOT Turning the Boiler Off when it should perhaps then the Frost Thermostat is being `Overridden` by the Operation of the Programmer / Switched `On` and then the Boiler / Heating System works correctly until the operation of the Frost Protection Thermostat again - ??


I would strongly advise that You contact the Boiler Manufacturer Technical Helpline to ask whether this CAN Happen as they would obviously know more about the `Internal Components and Electrical System` than We could ever `Diagnose` on here.

All of the Well Known Boiler Manufacturers have good Technical Helplines - although obviously they are run to be used by mainly Heating Installers / Engineers. - I would suggest that they will probably advise You that this should be looked at by a Boiler Servicing Engineer - You should obviously not speak as if You would be doing any work to the Boiler.

If that is the case You should definitely advise the People in the Home to arrange for an Engineer who actually works for the Boiler Manufacturer to Inspect / Test the Boiler - NOT an Independent Boiler Engineer - If only because the Manufacturers Engineer would have the Facility to Change the Frost Protection Thermostat straight away if He suspects that is causing the Problem - NOT `Have to Order the Stat`.

Obviously whether the Boiler is being Turned On by the Frost Protection Thermostat or the Programmer the Boiler [Heat] Thermostat governs the `Firing` of the Burners [Room Thermostat should not operate with Frost Protection] - SO even IF the fault is the Frost Thermostat causing the Boiler to be Turned On during the Night - the Boiler Thermostat [Heat Setting] will cause the Burners to be Turned On / Off.

I mention this in case anyone reading the Posts wonders why the Boiler does not just `Keep Firing` if turned on by the [Faulty ?] Frost Protection Thermostat.


I cannot think of any other cause of what You described - I hope to see a couple of opinions about the possibility of the Programmer Malfunctioning and causing this - ?


"Sorry" - that I cannot give You a Definitive Answer to this - In My experience it is a Unique Situation ! - as I have not encountered this - although a Boiler Service Engineer MAY have ?


Regards,


Chris

 

[drew35]

Hmm I'm just a lowly electrician but I find programmers that go faulty regularly, switching on when they're not set. I changed one on Saturday, that was Danfos. And I witnessed the fault when I went to look initially, the heating and hot water where both on, the hot water is always set to off, and the heating wasn't within its set demand time. The Y plan valve was operating correctly, I checked that, after switching the FCU on and off it sorted itself out. So I fitted a new programmer, sorted.

And there was another just a few weeks ago where the heating would come on outside its set time and not during the demand time. I didn't change that one I left it to someone who knows more as it was a complicated system at a village hall, but the guy who deals with the heating only changed the programmer. I thought this was common?

 

[chris murphy]

Hmm I'm just a lowly electrician but I find programmers that go faulty regularly, switching on when they're not set. I changed one on Saturday, that was Danfos. And I witnessed the fault when I went to look initially, the heating and hot water where both on, the hot water is always set to off, and the heating wasn't within its set demand time. The Y plan valve was operating correctly, I checked that, after switching the FCU on and off it sorted itself out. So I fitted a new programmer, sorted.

And there was another just a few weeks ago where the heating would come on outside its set time and not during the demand time. I didn't change that one I left it to someone who knows more as it was a complicated system at a village hall, but the guy who deals with the heating only changed the programmer. I thought this was common?

"Hello drew35",


Although I am a Heating Engineer I do not carry out Boiler Repair / Heating System Fault Call Out Work - I have spent My Self Employed Working Life Designing and Installing Heating and Plumbing Systems - It may well be that what You have described and Personally come across IS a fairly common occurrence - BUT I have never Found or Heard of it happening.

Just like Plumbers who carry out mainly Maintenance and Repair Plumbing Work - Boiler Service and Repair Engineers and Electricians probably come across what I would consider to be `Unusual Faults` on a regular basis - this Fault - If it is the Programmer that is Faulty - may be `Well Known` to Boiler Service and Repair Engineers but NOT to Heating Engineers who carry out Installation Works only.

I would be interested in finding out exactly what can occur within a Programmer that causes this situation to happen - ?

Could some other Electricians please comment on How Well Known the `Faulty Programmer` causing the Heating System to be Turned On during `Off Periods` situation is amongst their experience - ?

If I was involved in Investigating this Fault the FIRST Thing that I would do would be to Fit a Used Programmer to see IF it was the Programmer that was Faulty / `Rule Out` the Programmer - I have various Programmers that I have removed when Replacing or Upgrading Heating Systems - BUT I could NOT advise mcm to tell the People in the Home that they should Purchase a New Programmer when I had never heard of a Programmer causing this Fault.

Nor did I advise Him to arrange anything that would Cost Money - Unless it was confirmed by the Boiler Manufacturers Technical Helpline that the Boiler Frost Protection Thermostat COULD be causing the Boiler to be Turned On AND then NOT Turning it Off when the Boiler had `Warmed` to a situation when it was not at Risk of Freezing.

As You and the other Members on here know it is Very Different matter trying to `Diagnose` a Fault on either a Heating System / Boiler or an Electrical System / Component on here as opposed to actually being `On Site` where Testing or Swapping of Controls etc. can be carried out to `Rule Out` items / Find the offending Item.


I take it that My Post will now be deemed to be giving `Incorrect Information & Advice` ??


mcm - I hope that it does turn out that it IS the Programmer that is a Fault - at least it would be a fairly Inexpensive `Fix` by just replacing the Programmer.

As I have NOT come across this `Faulty Programmer causes Heating to come On during Off Periods` in the 40 Years of working in Heating - Plumbing & Gas - and I assure You that I answered Your Post in all sincerity - Could You Please Post the Outcome of what is found to be causing the Fault - "Thanks".


Chris

 

[PC Electrics]

Had one just last week, a Potterton EP2002. Usually a very reliable product, well liked by clients. This one had it's display go blank and it's lights were off, but the heating was running. Fortunately it was only a month old so was changed under warranty.

Question for the client: has the sysem always done this or is this a new problem and when did it start.
You could prove it's not the programmer by removing it from its base plate overnight and see if the problem recurs. You could temporarily wire up a 2G light switch to provide manual on/off control.

I would check (in this order):
frost stat
programmer
correctly wired

 

[chris murphy]

Had one just last week, a Potterton EP2002. Usually a very reliable product, well liked by clients. This one had it's display go blank and it's lights were off, but the heating was running. Fortunately it was only a month old so was changed under warranty.

Question for the client: has the sysem always done this or is this a new problem and when did it start.
You could prove it's not the programmer by removing it from its base plate overnight and see if the problem recurs. You could temporarily wire up a 2G light switch to provide manual on/off control.

I would check (in this order):
frost stat
programmer
correctly wired

"Hello PC Electrics",


An Excellent Idea - Would there be situations where the Wiring to the Boiler / Permanent Live for the Frost Protection Thermostat would be interupted by removing the Programmer - ?

I ASK this as I am not an Electrician and although I am `Trained and Registered` for the Defined Scope / Heating Appliance - Systems section of Part P - and I do know how to Wire Up the main types of System - I do not Wire Up My own Heating Systems - preferring to engage a Professional Electrician to carry out the Wiring and Notify and Certify the Work.

Obviously the Boiler would have to have a Live Feed in order that the Frost Protection Thermostat could work, But I am sure that if it is required a temporary Live Feed can easily be wired up.


Rather than Me trying to work out the Answer to that - I`m sure that You or another Member will answer that very quickly.

Also I would suggest that this is tried during a Forecasted Period of Cold Nights and left for a few Nights if necessary - not just One Night unless the Frost Thermostat IS Faulty and displays the situation where after Turning On the Boiler - It does NOT Turn it Off after a short period of time.


I should add a comment regarding Faulty Programmers - I have often seen / heard about Faults on Programmers - BUT - Never that they would Turn On the Heating at Night / Times that were NOT in the Settings - But then seem to Work Correctly for the rest of each 24 Hour period.


Chris

 

[sambotc]

Turn the room stat down to 0 over night. If the programmer is at fault, the stat will stop it from firing. If the heating comes on still you know it is from an external influence (e;g frost stat although unlikely to be the cause in my opinion)

 

[oldtimer]

First of al I take it is a domestic system where you have hot water storage tank and central heating yes ? plus you say it comes on itself so when does it come on ie low outside temp or internal thermostat so you need to find out how it is wired then as a test turn off the timer / programmer and then turn up the room stat if the boiler kicks in the the stat should be wired in series with the programmer I hear about frost stats but this is usally found on commercial systems ie schools office blocks etc

 

[chris murphy]

"Hello sambotc and oldtimer",


IF You saw My Posts `Addressed` to You earlier this evening - I must Apologise - I came here from a Link in a Post Notification Email and because I have been Writing Questions and suggestions on another Central Heating Problem I confused the Two Subjects.

I had Posted some answers to both of You - But I was writing about the OTHER Subject - "Sorry"

I am glad that I noticed this just before leaving the website or it would have made Me look as if I had Posted completely Irrelevant comments !

Also I Apologise to anyone else who read My Posts before I Deleted them - and wondered what I meant.


Regards,

Chris

 

[Guest111]

Hi had this happen to me a while ago turned out it was a motorised valve that was playing up,found out which by testing the grey wires to see which went live when it fired by itself,only problem is it aint easy to do when you dont live there as its pure luck catching it doing it,

 

[chris murphy]

Hi had this happen to me a while ago turned out it was a motorised valve that was playing up,found out which by testing the grey wires to see which went live when it fired by itself,only problem is it aint easy to do when you dont live there as its pure luck catching it doing it,

"Hello phil d",

I am interested in How a Zone Valve could Turn On the Boiler / Heating System if the Programmer is in the Off Setting / Period - So theoretically there is NO Power supplied to the Thermostats and Zone Valves - ?

I assume from what the Original Poster stated that the Heating System Wiring was `O.K.` until the recent malfunction occurred.

Regards,

Chris

 

[chris murphy]

Turn the room stat down to 0 over night. If the programmer is at fault, the stat will stop it from firing. If the heating comes on still you know it is from an external influence (e;g frost stat although unlikely to be the cause in my opinion)

"Hello sambotc",


The reason that I started writing about the Frost Protection Thermostat possibly turning on the Boiler at Night was because:

Firstly I had not heard about a Faulty Programmer turning On a Heating System / Boiler when it was in an `OFF` Setting and then apparantly Operating during the Day / Evening Correctly.

And because a Frost Thermostat on a Boiler is Designed to Independantly Turn On the Boiler - obviously in circumstances when the Boiler is `Off` on the Programmer - Although it is very unlikely that the Frost Thermostat would Turn On the Boiler AND then NOT Turn it Off again after `Warming Up` the Boiler - I doubt whether that is `Impossible` - ?


Regards,


Chris

 

[chris murphy]

First of al I take it is a domestic system where you have hot water storage tank and central heating yes ? plus you say it comes on itself so when does it come on ie low outside temp or internal thermostat so you need to find out how it is wired then as a test turn off the timer / programmer and then turn up the room stat if the boiler kicks in the the stat should be wired in series with the programmer I hear about frost stats but this is usally found on commercial systems ie schools office blocks etc

"Hello oldtimer",


Most Boilers from the well known Manufacturers that were made in certainly the last 10 to 15 Years have Built In Frost Protection Thermostats.


Regards,

Chris

 

[sambotc]

Hi chris,

It is possible, but as you say it would only raise the temperature to 20 odd degrees and the heating wouldn't be belting out as the op has described. As a heating engineer myself I would take a punt on the clock first but if the valve has jammed in the open position through sludge or corrosion then it will supply 230v to the boiler and pump. The valves have a permanent live supply, a switched live and a live supply to the boiler plus N and E ( hence 5 cores) so it is possible for the live supply to bypass the call of the clock if it malfunctions. I would have though that the customer would have also noticed the heating being on all the time. If you turn the room stat off you will cut the supply from timer ( assuming it's wired in series like most stats are on domestic heating) therefore eliminating the clock from the equation. If that solves it then the clock must be at fault, if not then you can look further into where the valve and essentially boiler and pump are getting a supply from.

 

[Guest111]

hi Chris on some sytems there is a permanent live to the junction box and I have had them were a 2 or 3 port valve has gone fault and this causes boiler to fire,was common on y plan when I did contracting for BG power to box is there at all times unless fcu turned off,hope this makes sense.phil

 

[chris murphy]

Hi chris,

It is possible, but as you say it would only raise the temperature to 20 odd degrees and the heating wouldn't be belting out as the op has described. As a heating engineer myself I would take a punt on the clock first but if the valve has jammed in the open position through sludge or corrosion then it will supply 230v to the boiler and pump. The valves have a permanent live supply, a switched live and a live supply to the boiler plus N and E ( hence 5 cores) so it is possible for the live supply to bypass the call of the clock if it malfunctions. I would have though that the customer would have also noticed the heating being on all the time. If you turn the room stat off you will cut the supply from timer ( assuming it's wired in series like most stats are on domestic heating) therefore eliminating the clock from the equation. If that solves it then the clock must be at fault, if not then you can look further into where the valve and essentially boiler and pump are getting a supply from.

"Hello Again sambotc",


I can see what You are stating - But - as You wrote the Heating System would then be ON all of the Time - If a Stuck Zone Valve can `Bypass the Programmer` regarding supplying a Live Feed to the Boiler and Pump.


Regards,

Chris

 

[chris murphy]

hi Chris on some sytems there is a permanent live to the junction box and I have had them were a 2 or 3 port valve has gone fault and this causes boiler to fire,was common on y plan when I did contracting for BG power to box is there at all times unless fcu turned off,hope this makes sense.phil

"Hello phil",

I believe that most Heating Wiring that is done using a Wiring Centre type connection Box has the Power Supply wired directly into the Wiring Box - From either an FCU or from a Three Pin Plug - ?

How does the Power get from this supply TO the Zone Valve without the `Involvement` of the Programmer and Thermostats - If the Programmer is in an OFF Setting ?

And how could a Zone Valve where the Heating has been OFF then supply Power to Turn On the Heating / Boiler & Pump in the middle of the Night - presumeably long after any ON Setting on the Programmer ?

I am genuinely interested in these points.


Regards,


Chris

 

[sambotc]

Chris,

The system is wired so that power from the programmer goes through a stat (water or heating) then to the valve. This actuates the motor to spin across to open which closes a microswitch, the microswitch turns the boiler/pump on, not the programmer. That is for a zone valve, a three port works differently but a similar principle. As the valve has a permanent live connection, it is possible for the valve to remain open and feed power to the boiler without a feed from the programmer.

 

[chris murphy]

Chris,

The system is wired so that power from the programmer goes through a stat (water or heating) then to the valve. This actuates the motor to spin across to open which closes a microswitch, the microswitch turns the boiler/pump on, not the programmer. That is for a zone valve, a three port works differently but a similar principle. As the valve has a permanent live connection, it is possible for the valve to remain open and feed power to the boiler without a feed from the programmer.

"Hello sambotc",

I hope that You are not getting annoyed / frustrated about My Questions ? - I am wondering this because of your `Details` about the Sequence that operates a Heating System - which I do know.


BUT - What motivated You to decide not to reply to this - from My last reply to You:





I can see what You are stating - But - as You wrote the Heating System would then be ON all of the Time - If a Stuck Zone Valve can `Bypass the Programmer` regarding supplying a Live Feed to the Boiler and Pump.


Regards,

Chris

 

[sambotc]

Hi chris,

No not annoyed at all, if it cam across like that I can only apologize. I'm actually on my mobile phone hence the bad grammar and blocks of text! I hope I explained it ok, as coming from the heating trade myself I appreciate it may not work how you had imagined?

I'm not quite sure what you mean on the above question that I missed, I thought I had explained that in the previous post or the power for boiler comes from the valve rather than programmer? If that's not what you were asking I'm sorry, maybe I am getting the wrong end of the stick.

I have to be honest I can't think of a time where I have come across a valve which jams the heating on, but as a live source is available in the valve it is possible, I can only presume it is not that common due to the internal design of the valve itself??

 

[chris murphy]

"Hello sambotc",


I just wanted to ask IF I was agravating You in some way with My Questions / Comments - As I definitely do NOT want to do that.


I was asking IF the Zone Valve was `Stuck` in the Open Position where the Microswitch would supply Power to the Boiler / Heating System - would that not mean that the Heating would be ON - Constantly ?

And as I mentioned in My Post to phil - The Boiler / Heating System in this particular Problem comes ON unexpectedly / at Night - How could a Zone Valve where the Heating has been OFF then supply Power to Turn On the Heating / Boiler & Pump in the middle of the Night - presumeably long after any ON Setting on the Programmer ?

I mention the Programmer again ONLY to indicate that the Heating would have been OFF for a period of Time before it `Comes On` at Night / Unexpected Times.

Just to add - I definitely know the Sequence that operates a Heating System Controls - and I have done for many Years.


Regards,

Chris

 

[sambotc]

Yeah it would mean it would be on all the time and as I say I haven't come across that personally myself, normally the valve will jan and allow water to pass or the motor will stop operating and the boiler won't fire.

I think we went a little bit off topic so I was not strictly relating this all to the above issue. Without a little more detail I think it would be hard to try and identify the issue on this particular problem.

Sam

 

[chris murphy]

Yeah it would mean it would be on all the time and as I say I haven't come across that personally myself, normally the valve will jan and allow water to pass or the motor will stop operating and the boiler won't fire.

I think we went a little bit off topic so I was not strictly relating this all to the above issue. Without a little more detail I think it would be hard to try and identify the issue on this particular problem.

Sam

"Hello again Sam",


This was always going to be `One of Those` - this type of Enquiry - although obviously Welcomed on the Forum - it is an example of WHY the `Diagnosis in the Pub` does NOT usually work !

As You know this kind of Problem can be thought about in terms of trying to work it out by `Process of Elimination` - BUT that must be combined with actual Testing of the Wiring / Components - in Situ.


Chris


P.S. I have replied to You on the Subject about the £200.00 Part P Course - Again this is NOT to contradict You - Just to Clarify My points.

 

[UNG]

Thinking about this had a problem on my own heating about 12 years ago just after I moved in (new build property) the system was wired to allow a pump over run so that residual heat in the boiler could be dissipated to avoid damaging the boiler. Under certain circumstances when the programmer turned the heating off the heating continued to run due to a back feed in the wiring turning the spur off and on again cleared it till the same conditions occurred again which could be a few days or weeks.

Quite entertaining watching the builders spark trying to locate the fault I even created the fault for him a few times and after a couple of hours had to tell him how to sort it out as he was getting no where

 

[invisable]

Thinking about this had a problem on my own heating about 12 years ago just after I moved in (new build property) the system was wired to allow a pump over run so that residual heat in the boiler could be dissipated to avoid damaging the boiler. Under certain circumstances when the programmer turned the heating off the heating continued to run due to a back feed in the wiring turning the spur off and on again cleared it till the same conditions occurred again which could be a few days or weeks.

Quite entertaining watching the builders spark trying to locate the fault I even created the fault for him a few times and after a couple of hours had to tell him how to sort it out as he was getting no where

I have seen the exact same problem before. people connecting the pump live with the boiler live a wiring centre, then also linking the pump live output at the boiler back to the same connection at the wiring centre.

MCM :
If your having problems with this system and you havnt found the fault and your sure its not a frost stat kicking in reccomend you go and pick yourself up a wiring centre (drayton LWC1) and follow the instructions they are so easy and that one mentioned has cable clamps to secure the cables. It may be quicker for you to do that then spend hours trying to trace back the wires to locate the fault charge the a hourly rate for how long it takes then you can be sure its not the wiring.
the reason im telling you this is because:
1) a programer fails it is very unlikley to just turn the boiler on for a few mins then turn it off
2) same with a valve sticking it willl stick or it wont stick it wont just stick in the middle of the night, what i mean is if a valve is stuck it will always be open like a tap eg heating will get hot when water is on. that would cause frost stat to heat up rads but they would have noticed the problem before when the just wanted hw on.

 

[chris murphy]

I have seen the exact same problem before. people connecting the pump live with the boiler live a wiring centre, then also linking the pump live output at the boiler back to the same connection at the wiring centre.

MCM :
If your having problems with this system and you havnt found the fault and your sure its not a frost stat kicking in reccomend you go and pick yourself up a wiring centre (drayton LWC1) and follow the instructions they are so easy and that one mentioned has cable clamps to secure the cables. It may be quicker for you to do that then spend hours trying to trace back the wires to locate the fault charge the a hourly rate for how long it takes then you can be sure its not the wiring.
the reason im telling you this is because:
1) a programer fails it is very unlikley to just turn the boiler on for a few mins then turn it off
2) same with a valve sticking it willl stick or it wont stick it wont just stick in the middle of the night, what i mean is if a valve is stuck it will always be open like a tap eg heating will get hot when water is on. that would cause frost stat to heat up rads but they would have noticed the problem before when the just wanted hw on.

"Hello invisable",


Regarding THIS part of your GOOD Advice:


QUOTE:

1) a programmer fails it is very unlikely to just turn the boiler on for a few mins then turn it off

2) same with a valve sticking it willl stick or it wont stick it wont just stick in the middle of the night, what i mean is if a valve is stuck it will always be open like a tap eg heating will get hot when water is on. that would cause frost stat to heat up rads but they would have noticed the problem before when the just wanted hw on.[/QUOTE]


I have been stating these [similar] points during My various Posts on this Subject - As I am a Heating Engineer - perhaps NOW that an Electrician has stated similar details the Original Poster and others will be able to view My points as `Valid` - ?


I Quoted those points of yours and stated that they were Good Advice - Not because the `Rewire with a Wiring Centre` was not Good Advice - I just wanted to identify the points that were similar to what I have been stating.


I was however under the impression that the Heating System had been operating correctly - until a Malfiunction caused the problem of the unscheduled On Periods - during the Night.

When I was Informed by a Member that it is `Quite Usual` to come across a Programmer Malfunctioning that can cause this - and then Work Correctly for the rest of the time / Day - I was Surprised - I could NOT imagine this occurring - but that scenario was then Confirmed by another Member - I had to comment that perhaps I just did not know of this happening - let alone on a regular basis - Words to that effect.


Perhaps We might find out the Result of rectifying the Problem - although it has been Unresolved for quite a while now.


Regards,


Chris

 

[sambotc]

See personally, my theory would be that a rewire or similar (change of wiring centre for example) would be the last thing on my list of things to explore given the fact that it is very unlikely for the wiring to fail or change by its on accord? Personally, anything with a mechanical element would be my first point of call as this is more likely to fail or change by itself.

I'm not saying i'm right, or that this is the way it should be done, just advising of my way of thinking when trying to fault find a problem like this.

Given the fact the OP has not updated this post in a while now, ,I would say that it has either been fixed, or interest has been lost so I think i'll unsubscribe to the thread now, I hope it has been rectified and it would have been nice to hear what the offending object was.

Sam

 

[chris murphy]

See personally, my theory would be that a rewire or similar (change of wiring centre for example) would be the last thing on my list of things to explore given the fact that it is very unlikely for the wiring to fail or change by its on accord? Personally, anything with a mechanical element would be my first point of call as this is more likely to fail or change by itself.


I'm not saying i'm right, or that this is the way it should be done, just advising of my way of thinking when trying to fault find a problem like this.

Given the fact the OP has not updated this post in a while now, ,I would say that it has either been fixed, or interest has been lost so I think i'll unsubscribe to the thread now, I hope it has been rectified and it would have been nice to hear what the offending object was.

Sam

"Hello Sam",


When I stated that I was under the impression that the Wiring was `O.K.` - with the Heating System having been operating correctly [?] previously.

And that a `Malfunction` then occurred which caused the present Problem.

Plus all of the possibilities that You and I `Discussed` on here - I was basically asserting that it would be Unlikely that this is a Wiring Fault - BUT - in light of the Fault having NOT been identified - ?

I think that I also asked that the result of identifying the Fault be Posted on here for the interest of `Us` who had replied to the Original Poster - IF they are still involved - ?


Regards,


Chris

 

[invisable]

Looks like this problem will remain unsolved as mcm has not replied for a while.
Chris:
I agree with you I used to wire about 6 heating a week (mainly y plans) for a company that used to install them for the council all around Sussex .We used to get the odd valve failing and sticking, and programers that just had stopped working or stuck in the on posistion, sometimes when you isolate the power to the programmer then turn it on this can stop/reset it but never in my time, have i ever seen a programer that just decides to turn the heating on and off in the middle of the night. They just tend to stay on untill there isolated.

About the rewire bit I assumed it was a new install so I take back the statement about the rewire, as it would unlikely be a wiring fault
I bet it was something simple one last thing I would check if I was mcm is that the customer hasnt reset the time on the programmer after the clocks changed and now pm and am is round the wrong way so there afternoon heating boost is coming on at 1 in the morning rather then 1 in the afternoon.

e

 

[chris murphy]

Looks like this problem will remain unsolved as mcm has not replied for a while.
Chris:
I agree with you I used to wire about 6 heating a week (mainly y plans) for a company that used to install them for the council all around Sussex .We used to get the odd valve failing and sticking, and programers that just had stopped working or stuck in the on posistion, sometimes when you isolate the power to the programmer then turn it on this can stop/reset it but never in my time, have i ever seen a programer that just decides to turn the heating on and off in the middle of the night. They just tend to stay on untill there isolated.

About the rewire bit I assumed it was a new install so I take back the statement about the rewire, as it would unlikely be a wiring fault
I bet it was something simple one last thing I would check if I was mcm is that the customer hasnt reset the time on the programmer after the clocks changed and now pm and am is round the wrong way so there afternoon heating boost is coming on at 1 in the morning rather then 1 in the afternoon.

e

"Hello invisable",


As You wrote it can often be `Simple` things that are the cause of Central Heating `Faults`.

I have found a couple of times on this Forum that in the process of Posting Questions and `Advice` in order to TRY and `Diagnose from a Distance / Description` - that the Original Poster refuses / declines to Answer Questions which having the Answers to would help All of Us to eliminate items from being the cause of their Problem.

This has happened to Me quite recently - Even when I posted a Request / Reminder which was `Addressed` to the Original Poster He still did NOT Answer My Questions - I had written some Very Long Posts about His Boiler Problem and when I asked directly that He Answer some Questions that I had previously Posted to Him - and Had He tried a particular Operation on the Heating Programmer ? - He still did NOT Answer !

I felt that this was VERY Disrespectful and that I had Wasted My Time !

Basic `Courtesy` would suggest that He would NOT just Ignore My requests for those Answers - And then Defy My second Request - I was responding to HIS Boiler Problem - the Answers might have enabled Us to eliminate some of the possible causes of the Problem.


I am Definitely NOT the `Over Sensitive` Type - BUT - I will Definitely NOT continue Writing Answers / Suggestions / Questions when People seem to decide to Completely Disregard My attempts to HELP Them !


Regards,


Chris

 

[oldtimer]

Chris I totally agree with you I also have noticed a trend where the originator asks the question then we try and tease more information out of them and then i find we are all discussing it to death meanwhile the originator does not even get back to tell us if it is fixed and what was wrong as I said this forum is to help each other out but I am finding more and more that we appear to have a lot of serial DIYers pretending to be sparks and I know that everybody does not know everything but like you I think i will pass on some of these posts

 

[chris murphy]

Chris I totally agree with you I also have noticed a trend where the originator asks the question then we try and tease more information out of them and then i find we are all discussing it to death meanwhile the originator does not even get back to tell us if it is fixed and what was wrong as I said this forum is to help each other out but I am finding more and more that we appear to have a lot of serial DIYers pretending to be sparks and I know that everybody does not know everything but like you I think i will pass on some of these posts

"Hello oldtimer",


"Thanks for your reply"


Something that particularly irritated Me regarding the example that I mentioned was that the first response to Me completely disreguarded everything that I had written and Asked.


The Reply which was `Addressed` to My Name did NOT refer to a single thing that I wrote - it was as if EVERYTHING that I wrote was Irrelevant !

When I then ASKED Him to `Please reply to My Questions as this would Help ALL of Us to eliminate some possible items` - Words to that effect - I did NOT receive a Reply.


I regard that as Insulting !


I was trying to Help Him to identify what the Problem was primarily BECAUSE He had not tried to infer that He had any Electrical Knowledge - and because British Gas had not been able to Find the cause of the Problem.

I think that He may have decided that as He had Heating System / Boiler Cover with British Gas - He would `Leave it to Them`.

In which case IF You are NOT prepared to Answer the Questions that are asked of You on here by People who are genuinely Trying to Help You - Don`t Post your Problem on here !

THIS MAY NOT BE THE ATTITUDE OF THE MODERATORS / ADMINISTRATORS ON THIS FORUM - IT IS JUST MY OPINION ON THE MATTER.


Before someone `reminds` / informs Me that this kind of Behavior is Frequent on ALL Forums - I know that - But it does not mean that I should NOT Comment upon it.


Regards,


Chris

 

[mcm]

Update on problem.

After posting first of all I asked a friend who I used to work with to look at it, as he used to wire all the boilers.

He went round and said it was the programmer so changed programmer and still same problem. Went back today to check all wiring and all seems ok. Wiring is as following:

Live, neutral and earth from spur to programer.
Ch on to wiring centre joined to white of 3 port valve.
Hw on to wiring centre from programer joined onto cylinder stat.
Return on cinder stat connected to live to boiler and Orange on 3 port valve.
Satisfied from cylinder stat joined to grey on 3 port valve. The programmer does not have a Hw off that should be joined also with the grey on 3 port valve. This is not a problem as they have the Hw set on all the time.

All the wiring seems to be ok if the above is correct. But the ch does not seem to switch off even with the programmer turned off.

Tested voltage on Hw on only at Orange of 3 port valve and gives 230v if stat is turned down 230v goes away.

At white of valve reading 230v with Hw on and ch off. Disconnected white at programmer and getting 230v still but nothing on cable to programmer meaning voltage coming from valve side. Is this correct for the valve to bring the white live when Hw is on? Or is it possible its back feeding at valve causing ch to come live?

Sorry for the long reply

Thanks

 

[invisable]

It's the 3 port valve then. This is what valves tend to do when they go. I have a question what sort/ make of 2 chanel programmer doesn't havnt a hw off, it would be nice to know so I never fit one. Good luck

 

[mcm]

Hi invisible

The programmer has a hot water off its the wiring that is missing the core from programmer to the 3 port valve connected to grey on valve and satisfied on cylinder stat.

As above when the Hw was on the ch was off it was giving 230v on white on 3 port valve coming from valve side not programmer. So you think it will be the valve faulty?

Thanks

 

[invisable]

Sounds like it.
Can you discconect the valve from the wiring centre (if it wired like that) then just check your cables coming back from the programmer then you could be 100% sure.
As mentioned before in this thread if it was working fine before then it is more than likley it would always be a bit of faulty equipment and it is normally the valves that go, and when they go that is what normally happens.

 

[brooky25]

Hi, Been to a job today with exactly the same kind of symptoms. Boiler firing up in the middle of the night when programmer is turned off but the pump is not running so pipes are banging because of heat waking the customer up. Thought it was a problem with frost stat as this is what plumber said to me. This is a s plan system but boiler is in garage, side of boiler is a 15 amp switch and frost stat. Also there is a pipe stat above boiler. Cannot understand why it would have a pipe stat as I thought boiler would have a built in overheat stat and frost stat. When I turned up the pipe stat from 20 c to 40 c the boiler fan fired up ? So basically when pipe stat falls below 20 c it fires up the boiler. Back of frost has a perm live into terminal 3 which should be sw feed back up the yellow in my book? this has confused me all afternoon and hopefully I have now sorted problem by removing the pipe stat. I thought that the pipe stat would be for overheat not call or am i wrong.
Any advice would be great to clear my head up
thanks

 

[chris murphy]

Hi, Been to a job today with exactly the same kind of symptoms. Boiler firing up in the middle of the night when programmer is turned off but the pump is not running so pipes are banging because of heat waking the customer up. Thought it was a problem with frost stat as this is what plumber said to me. This is a s plan system but boiler is in garage, side of boiler is a 15 amp switch and frost stat. Also there is a pipe stat above boiler. Cannot understand why it would have a pipe stat as I thought boiler would have a built in overheat stat and frost stat. When I turned up the pipe stat from 20 c to 40 c the boiler fan fired up ? So basically when pipe stat falls below 20 c it fires up the boiler. Back of frost has a perm live into terminal 3 which should be sw feed back up the yellow in my book? this has confused me all afternoon and hopefully I have now sorted problem by removing the pipe stat. I thought that the pipe stat would be for overheat not call or am i wrong.
Any advice would be great to clear my head up
thanks

"Hello brooky25",


I am a Heating Engineer - the reason for the Pipe Thermostat being fitted in conjunction with the Frost Thermostat is because the Boiler only needs to Fire occasionally for Short Periods of Time during Cold Temperatures to Stop it from Freezing - the Boiler does NOT need to Fire until the Boiler Thermostat Setting is reached.

The Pipe Thermostat is fitted so that the Boiler only Fires to remove the Immediate `Threat` of Freezing - So it does not need the Boiler to reach a High Temperature such as would be on the Boiler Thermostat Setting.

However from what You described it sounds like it was NOT wired Correctly - it should only be operating in conjunction with the Frost Thermostat - and I am assuming that it was not Cold enough when You were doing this to have caused the Frost Thermostat to be in Operation [?].


I would advise You to refit the Pipe Thermostat as the Combination of a Frost Thermostat and a Pipe Thermostat IS the Correct Method of providing Frost Protection for the Boiler in this instance.


Regards,


Chris

 

[brooky25]

Many thanks for the advice Chris, I do believe you are right iv'e been thinking about this all night. I am going to go back and sort the problem. The trouble is new tennants have only been in property 3 weeks and previous tennants have moved to Aus, so I don't know how long the problem has been there or who has messed with it. Need to start from beginning with this as in my head there should be sl,n,e going to boiler from orange on valves to call for heat and perm l,n going to frost stat then sw out of frost stat through pipe stat back to call on boiler. Am I correct ?

P.s Sorry for hijacking this thread

 

[chris murphy]

Many thanks for the advice Chris, I do believe you are right iv'e been thinking about this all night. I am going to go back and sort the problem. The trouble is new tennants have only been in property 3 weeks and previous tennants have moved to Aus, so I don't know how long the problem has been there or who has messed with it. Need to start from beginning with this as in my head there should be sl,n,e going to boiler from orange on valves to call for heat and perm l,n going to frost stat then sw out of frost stat through pipe stat back to call on boiler. Am I correct ?

P.s Sorry for hijacking this thread

"Hello brooky25",


Sorry if this is Disappointing - But I will have to `Bow` to Your Electrical Knowledge / Any wiring Diagrams that You can find online / on Here - as I cannot remember How a Frost Thermostat and Pipe Thermostat should be wired.


In the Past My Heating Systems have usually been wired by a Qualified and [about last 6 - 7 Years] Registered Electrician - as it was always required by the Client that ALL Electrical Works were Tested and Certified by an NICEIC Registered Electrician / Electrical Company.


Although I do know how to Wire Up various Heating Systems `S Plan` etc. - the addition of a Frost Thermostat and a Pipe Thermostat would always require Me to be able to read the Wiring Diagram / Wiring Details.

Could I suggest that You go onto the Honeywell website where I am fairly confident that You will be able to find the Wiring Diagram for a Heating System which includes a Frost Thermostat and a Pipe Thermostat - as these Two Stats should always be used in conjunction with each other.


IF You have Time I am sure that some of the Extremely Helpful Electricians / Electrical Engineers on here will be able to perhaps Post a Diagram for these Thermostats to be wired to an `S Plan` System.


Regards,


Chris


EDIT - I have found and Attached a Screenshot from the Honeywell website regarding Frost Protection Thermostats - I hope that it will be Helpful in Identifying the Wires and where they are connected.


Chris

 

[brooky25]

Thank you very much for your help Chris, after your explanation of why pipe stats are needed I have found out what the problem is. Thinking back to how its been wired ( altered ), they have wired both stats in parallel not series and I think pipe stat is on flow not return. After a quick search I now fully understand how the system works and how it should be wired. Someone has definatly altered the circuit, most prob plumber. This is what has thrown me. I am a Niceic registered electrician but these heating systems I rarely come across. All will be wired as it should be and I will post the outcome. I always seem to get jobs that others have tried and failed at to rectify. Thanks for helping me get it clear in my head it seems so simple now. (Must have had a blonde moment)
Thanks again
Lesson learnt, Never listen to a plumber who does not know how the system works

 

[chris murphy]

Thank you very much for your help Chris, after your explanation of why pipe stats are needed I have found out what the problem is. Thinking back to how its been wired ( altered ), they have wired both stats in parallel not series and I think pipe stat is on flow not return. After a quick search I now fully understand how the system works and how it should be wired. Someone has definatly altered the circuit, most prob plumber. This is what has thrown me. I am a Niceic registered electrician but these heating systems I rarely come across. All will be wired as it should be and I will post the outcome. I always seem to get jobs that others have tried and failed at to rectify. Thanks for helping me get it clear in my head it seems so simple now. (Must have had a blonde moment)
Thanks again
Lesson learnt, Never listen to a plumber who does not know how the system works

"Hello brooky25",


I Edited My last Post to Attach a Small Wiring Diagram from the Honeywell website - From the Frost Thermostat section - this shows the Wires from the Frost Thermostat and Pipe Thermostat - and where they are connected to in various Wiring Plans.


I expect that you have already worked out what goes where or found a `Full` Wiring Diagram - BUT - Just in case this Helps You or others - I was Pleased to Post it.


Regards,


Chris