Circulation pump permanently on

[rolyberkin]

Can anyone help, I have looked at a central heating pump for my brother in law (who is a plumber!? it is an HRM oil fired boiler, the problem is that the circulation pump is permanently on, there is underfloor heating with the system, the wiring is shocking and I will probably have to re wire everything but just looking at a quick fix prior to pulling it all out and starting again.

I tested everything out a few weeks back and changed the head on one of the two port valves which appeared to solve the problem, I then left and then it has started running permanently again?

Any ideas as I am a bit lost, is it likely to be some kind of pump over run issue?

Thanks

 

[HandySparks]

I think the best thing is to trace the pump supply wiring back to the various things it might be connected to (boiler, valves, etc.) and see which one is providing the unwanted feed.

 

[Midwest]

Can anyone help, I have looked at a central heating pump for my brother in law (who is a plumber!? it is an HRM oil fired boiler, the problem is that the circulation pump is permanently on, there is underfloor heating with the system, the wiring is shocking and I will probably have to re wire everything but just looking at a quick fix prior to pulling it all out and starting again.

I tested everything out a few weeks back and changed the head on one of the two port valves which appeared to solve the problem, I then left and then it has started running permanently again?

Any ideas as I am a bit lost, is it likely to be some kind of pump over run issue?

Thanks

Expect its probably the other head gone now.

 

[streamer]

I had a faulty valve head a while ago and changing it solved the problem for a short time. When the replacement stopped working I took it off and realised the valve itself had become very stiff which is probably what caused the first one to pack in. A bit of WD40 on the valve fixed it.

 

[rolyberkin]

I am convinced it is one of the valves however I wondered if the boiler has a pump run on thermostat or device, I wondered whether that was faulty and when it got up to temperature permanently on?

 

[Last plumber]

Is it just the pump that runs or is the Boiler on with it ?

Or does the Boiler work as it is expected ?

Is this a proper S PLAN ? ( I know there's more than one Two port MV but how many? and what on? )

If it's a correctly wired S plan then the supply to the pump will either come from the Orange ( normally ) wires off the two ports or from the Boiler (for the over run) as you mentioned.

If it's not wired correctly then as you know it could be anything ( cylinder stats, room stats, frost stats for example).

If I ever come across problems like this and it's not obvious, I always disconnect everything and start again. More often than not it is easier and quicker than trying to identify what someone else did wrong or trace/find a back feeds from something or find faults .

 

[rolyberkin]

Thanks, yes I think the whole thing is a crock of ---- and needs rewiring, I have never seen such a bodge and In think his woes started around the time he had an underfloor zone added on. I will go up there and do it for him, the problem is I am in Essex, he is in Lincolnshire, payment will no doubt be a curry and beer!

As I recall I think there are three two port valves, one for heating, one for hot water and one for an underfloor heating zone, cannot remember what controls he has, will have to get him to send me some pics. I am not 100% confident on fault finding heating systems so will do me the world of go and re wire it.

 

[Last plumber]

https://www.google.co.uk/url?sa=t&r...grams/&usg=AFQjCNFjsJcuWESICU-mMKNYXnAwssUi-g



Have a look at this link. There are lots of wiring diagrams on here that might help you if you're not used to it.

 

[rolyberkin]

I have rewired the whole heating system to which this post relates on Saturday and when I left (to travel to Essex from Lincolnshire!) everything was fine. I replaced all cables, there are three two port valves, one for heating, one for hot water and one for underfloor. There is Drayton twin programmer for CH and HW and separate wireless programmer for the underfloor. The UFH and CH are not currently switched on and my brother in law has just called to say that the pump is running when HW is put on timed or constant the pump is on constantly. I stayed overnight on Saturday and the water was set on constant and pump was not running continuously. I have today got him to turn off the two other zones and run just the hot water and the pump is running constantly, sticky valve or knackered microswitch or wiring faux pas? Anyone got any ideas?

 

[Midwest]

Without going back thru, could it be the heads gone on one of the valves? Had it on my own CH/HW system? Can't remember now, but nc or no contacts were u/s, causing constant demand to boiler.

 

[Leesparkykent]

I have rewired the whole heating system to which this post relates on Saturday and when I left (to travel to Essex from Lincolnshire!) everything was fine. I replaced all cables, there are three two port valves, one for heating, one for hot water and one for underfloor. There is Drayton twin programmer for CH and HW and separate wireless programmer for the underfloor. The UFH and CH are not currently switched on and my brother in law has just called to say that the pump is running when HW is put on timed or constant the pump is on constantly. I stayed overnight on Saturday and the water was set on constant and pump was not running continuously. I have today got him to turn off the two other zones and run just the hot water and the pump is running constantly, sticky valve or knackered microswitch or wiring faux pas? Anyone got any ideas?

Is the pump connected to the oranges of the valves or does the boiler have pump over run?

 

[rolyberkin]

Pump is connected to the orange wires, I have told him to turn off the UFH programmer and the heating side of the programmer and the hot water is constantly on, I think the next plan has to be to change the HW two port valve?

 

[Leesparkykent]

Pump is connected to the orange wires, I have told him to turn off the UFH programmer and the heating side of the programmer and the hot water is constantly on, I think the next plan has to be to change the HW two port valve?

Hmm that's strange...If the pump is running its getting 230V from somewhere which would also fire the boiler. Is there a separate wiring centre for the UFH heating?

 

[rolyberkin]

The Hot Water is constantly on when turned on at the time clock, i.e not cutting out, I think the boiler is also firing constantly. I have wired the UFH pump to a separate wireless time clock/thermostat as only one zone and working with what was there. Now starting to doubt my wiring although at the weekend everything seemed to be working okay?

 

[Leesparkykent]

The Hot Water is constantly on when turned on at the time clock, i.e not cutting out, I think the boiler is also firing constantly. I have wired the UFH pump to a separate wireless time clock/thermostat as only one zone and working with what was there. Now starting to doubt my wiring although at the weekend everything seemed to be working okay?

If the is the boiler constantly firing when the timeclock is constantly on or is it boiler constantly firing even when the timeclock is set to off?

 

[rolyberkin]

When time clock is on the pump on and boiler was firing, when time clock off everything off. When you turn all off and then turn on individually the respective zone the correct valve and pump/pumps combinations work and the boiler fires. When I was there on sat night after a well earned few beers the pump was still running and I was concerned the problem was still there. I got up and turned the rooms stat down on the CH and it all switched off. He has phoned me today so I wonder if the valve is sticking intermittently?

 

[Leesparkykent]

When time clock is on the pump on and boiler was firing, when time clock off everything off. When you turn all off and then turn on individually the respective zone the correct valve and pump/pumps combinations work and the boiler fires. When I was there on sat night after a well earned few beers the pump was still running and I was concerned the problem was still there. I got up and turned the rooms stat down on the CH and it all switched off. He has phoned me today so I wonder if the valve is sticking intermittently?

sounds like a wiring issue to me. generally when two port valves stick the boiler will still constantly fire when off at the programmer as the micro switch is closed between grey which is perm live and orange which is switched live to boiler/pump.

 

[rolyberkin]

Thanks, I think it is therefore probably backfeeding through the UFH zone, needs a circuit diagram today.

 

[Last plumber]

The Hot Water is constantly on when turned on at the time clock, i.e not cutting out, I think the boiler is also firing constantly. I have wired the UFH pump to a separate wireless time clock/thermostat as only one zone and working with what was there. Now starting to doubt my wiring although at the weekend everything seemed to be working okay?

Bit odd !
It sounds like it could be either a sticky micro switch or a wiring fault to me.

The only doubts I have about a wiring fault is that you just re wired it !

The doubts I have about microswitch is that the clock wouldn't stop it running ( if wired correctly).


To rule it out micro switch disconnect orange and grey on each valve and test continuity, there shouldn't be any when valves are closed. It won't necessarily be the hot water micro that's stuck
( if it is that ).

Where's your PL to grey from? No switches involved in that are there?
Room / cal stats etc to just brown on valves ?

 

[rolyberkin]

I will have to go back to fault find, the UFH zone is not controlled by the same programmer as the CH and HW, it has its own wireless programmable rooms stat. I have wired the UFH and the additional pump via the feed from the additional programmer, I wonder if this is in some way back feeding the CH pump? Everything in isolation was working fine on Saturday.

 

[rolyberkin]

If you have an SL (orange) from the UFH valve to that pump (UFH) and to the boiler and the boiler and CH pump are fed from the orange on the other two then when the UFH valve is open, there will be a back feed from the UFH orange via boiler SL to CH pump and vice versa, yes.
In that case you could use contactor sets for the boiler SL and pumps, (Two two pole, one for each pump use orange to throw contact set).

If it needs a pump over run, you will have to incorporate a delay timer

Thanks for your time, I have wired the live from the independant wireless timer/thermostat to the UFH pump and then also the brown on the UFH zone valve. The CH pump and boiler being connected via the orange wire. To my mind when the thermostat calls for heat the UFH pump should immediately switch on, then the zone valve would energise kicking in the boiler and CH pump. When the zone is up to heat the thermostat should switch off turning off the UFH pump and then de energising the zone valve and turning off the s/l to boiler and pump?
Alternatively when the CH or HW turn on they should not turn on the independent UFH pump? Am I missing something?

 

[rolyberkin]

The only thing I didn't rewire on Sat was the CH pump as it had been installed at a wonky angle, and I couldn't get the front off how about the internal wiring in the pump is reverse polarity and back feeding that way?

 

[Last plumber]

The only thing I didn't rewire on Sat was the CH pump as it had been installed at a wonky angle, and I couldn't get the front off how about the internal wiring in the pump is reverse polarity and back feeding that way?

No, I can't see it to be honest.

 

[rolyberkin]

Thanks yes thanks for your help makes sense, never used a contact set as have always used a wiring centre with a separate UFH pump terminal, I take it you mean a 2 pole 240v relay. Is there any preferred make or setup?

 

[Last plumber]

DAN.
can you help me with this.
I want to post a link to that item without advertising for RS online.

 

[Lou]

I have deleted your posts as requested.

You can PM @rolyberkin by using the envelope in the top right corner or by clicking on his profile.

 

[Last plumber]

I have deleted your posts as requested.

You can PM @rolyberkin by using the envelope in the top right corner or by clicking on his profile.

Done that already

Thanks, Senior moment !

 

[Midwest]

Thanks for your time, I have wired the live from the independant wireless timer/thermostat to the UFH pump and then also the brown on the UFH zone valve. The CH pump and boiler being connected via the orange wire. To my mind when the thermostat calls for heat the UFH pump should immediately switch on, then the zone valve would energise kicking in the boiler and CH pump. When the zone is up to heat the thermostat should switch off turning off the UFH pump and then de energising the zone valve and turning off the s/l to boiler and pump?
Alternatively when the CH or HW turn on they should not turn on the independent UFH pump? Am I missing something?

Not an expert on heating systems, but did an UFH last year. Seem to remember the thermostat for the UFH switched the zone valve for the UFH, via the orange wire. The UFH pump is given a live feed, and operates via the mixer valve and just keeps turning on & off, blending the heated water from the boiler with the loop for the UFH?

 

[Midwest]

Ps, it's all flooding back to me!

UFH stat calls for heat & opens the UFH zone valve, which in turn ask the boiler/pump to turn on, for heated water. Meanwhile, UFH mixer valve & pump, who live in a world of their own, sense there's some lovely hot water to blend, and open & start pumping around the loop. When UFH stat cancels call for heat, UFH zone valve closes, and after a short period UFH mixer valve & pump, sense the good times are over and close & stop.
Any how, that's how the manufacturers rep explained it to me, I think

 

[rolyberkin]

Unfortunately as this is a stand alone single circuit and the previous sparks didn't put in a dedicated wiring centre which I would normally use which has the ability to setup multiple pumps, I think I need either a different wiring centre or to put in a relay to stop the second pump back feeding the HW/CH pump, however I keep looking at the wiring diagram and can't work out where the back feed is coming from, got them pulling the wireless receiver tonight to see if that solves it!:-( I wouldn't mind but he is plumber by trade, he should be able to do his own wiring!

 

[Last plumber]

I've seen single circuit UFH's with a separate supply for the pump from a fused spur and the pump works off a stat (in the manifold), like midwest is describing and the valve is just used to isolate that circuit, (stop flow).
If there is more than one loop, it needs more control over the pump. That's when you normally see the wiring centres, as I remember.

Unfortunately as this is a stand alone single circuit and the previous sparks didn't put in a dedicated wiring centre which I would normally use which has the ability to setup multiple pumps, I think I need either a different wiring centre or to put in a relay to stop the second pump back feeding the HW/CH pump, however I keep looking at the wiring diagram and can't work out where the back feed is coming from, got them pulling the wireless receiver tonight to see if that solves it!:-( I wouldn't mind but he is plumber by trade, he should be able to do his own wiring!

Does the manifold have a stat built in for the pump ?

 

[Leesparkykent]

The bodge way is to connect the UFH pump to the brown of the UFH 2 port valve and call for heat from the UFH thermostat. The ideal way is to connect the UFH pump to the coil of a relay along with the orange of the UFH 2 port valve.

 

[rolyberkin]

I've seen single circuit UFH's with a separate supply for the pump from a fused spur and the pump works off a stat (in the manifold), like midwest is describing and the valve is just used to isolate that circuit, (stop flow).
If there is more than one loop, it needs more control over the pump. That's when you normally see the wiring centres, as I remember.


Does the manifold have a stat built in for the pump ?

The manifold doesn't have a stat built in, it is acting like a heating circuit, one zone valve, wireless thermostat/timer.

 

[rolyberkin]

The bodge way is to connect the UFH pump to the brown of the UFH 2 port valve and call for heat from the UFH thermostat. The ideal way is to connect the UFH pump to the coil of a relay along with the orange of the UFH 2 port valve.

I have taken the bodge approach, will
Go back, check wiring and put in a relay! Thanks.