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Plumberpro, Plumber
Category: Plumbing
Satisfied Customers: 634
Experience:  Heating and plumbing answers. 20 years experience
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My pump keeps running even though central heating is off

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My pump keeps running even though central heating is off
Hi , sounds like the boiler PCB has failed
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Customer: replied 2 years ago.
Old Ideal W2000 RS50 boiler does not appear to have PCB in?
Hi , OK ,helps now have the model of your boiler. The pump may be getting a live feed from the programmer. Can you tell me the model of your programmer, if you have a room stat , a hot water cylinder stat and if you have two motorised valves or one ,please.
Customer: replied 2 years ago.
Hi, thanks for your reply. I have a room stat, a cylinder stat, 1no motorised valve & I can get the make of controller once I get home. Cheers
Hi , could you take the front of the programmer off ,leaving the back plate on, please and see if they pump stops, thanks
Customer: replied 2 years ago.
Hiya it's a Siemens TWB29 programmer and the pump does stop when the front is removed. Many thanks
Hi , its quite a strange one as the boiler and pump usually liven up at the same time , so if the pump is running the boiler would normally fire up as well. . does your motorised valve have two pipe connection or three?
Customer: replied 2 years ago.

Hello, it has 3 pipe connections!

OK , thanks. Can you see where the pump is wired into , is it a wiring junction box or the boiler ?
Customer: replied 2 years ago.
Programmer, 3 port valve and pump are all wired into a box in the airing cupboard. Thanks

Hi, this may be a bit awkward. But could you check where the electricity comes into the boiler ? To check there is a separate connection for the pump . thanks. there must be a pump overrun on the boiler that may be linked to a stat, either overheat or frost stat, that is faulty .

Customer: replied 2 years ago.
The pump, valve & boiler share a connection in the box in the airing cupboard. Inside the box are a series of loose chocolate block connectors joining all the relevant accessories. From what's in front of me I would say they share a power source. Please let me know if I've not answered your query. Cheers
Hi , that's fine thank you . would you be able to check the boiler wiring ? just need to check if there is more than three wires going in , live neutral, earth. As if there is an extra wire this may be a pump over in from the boiler , thanks
Customer: replied 2 years ago.
Just live, neutral & earth .
OK , thanks . does the heating and hot water work OK?
Customer: replied 2 years ago.
Yes both work okay it's just the pump is constantly running
Hi , would you mind taking the wire temporarily out of hot water off on the programmer back plate?
Customer: replied 2 years ago.
Im happy to do that but know which wire it is?
Customer: replied 2 years ago.
I believe I've done it.
That's great.I take it the pump stopped ?
Customer: replied 2 years ago.
Yes it did
OK , I think the fault is either with the cylinder stat or motorised valve , most likely they motorised valve . but could you try hot water on only with room stat off, and see if the radiators still get hot . I guess this will happen , but would be good to confirm , thanks
Customer: replied 2 years ago.
No, the room stat is off and the radiators are cold but hot water is on
OK , that's good , how about the other way round with heating on does the pipe into cylinder get hot?
Customer: replied 2 years ago.
All the pipes are red hot without doing anything
Hi , well done , thanks for your patience. Replace the motorised valve and the hit water off wire and your problem should be solved
Customer: replied 2 years ago.
Sorry,but a new valve was fitted yesterday to overcome this problem so I'm not convinced. Any more suggestions?
Customer: replied 2 years ago.
What does hit the wire mean please?
Then could be the cylinder stat is faulty as the hot water off gets routed through it . was anything done to the system before the issue with the pump?
Customer: replied 2 years ago.
System cleaned and water replaced about a week and a half ago!
Hit wire , was refit the wire.
System flushed , that could messed up the motorised valve , but that's been changed. It can only be the cylinder stat . luckily fairly easy to replace .
So just to confirm , system flushed , nothing else , then pump continuously running .?
Customer: replied 2 years ago.

System flushed, heating wouldn't then turn off, new m/valve fitted which sorted turning heating off, but pump still running. That's it. I'll try the cylinder stat tomorrow and let you know the result. Many thanks for your time and patience. You will certainly be getting positive feedback from me. Best wishes

OK , your welcome, thanks. Likewise too
Customer: replied 2 years ago.
Hi, changed tank stat & all is quiet at the moment, could just be that I've wired it wrong though. Many thanks
That's good , hopefully all OK .
Customer: replied 2 years ago.
All working properly now, thanks very much. No need to reply