CH turning on by itself problem

[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