Central heating pump on continuous

[Edward67]

Hi

I have just had my boiler replaced which was a potterton suprima 60l. Heat only boiler as it kept cutting out.
I have had a vailent ecofit 425 fitted by engineer but now my pump is running continuously.
This wasn't the case before.
It's s plan with two heating 2 port valves and 1 hot water two port valve.
I have two stats and they are both 3 core.
The boiler as far as I can tell has live neutral and earth the a second cable linked with live which. I think goes to the pump and another in rt.
I have checked boiler setting and they Re set too intermittent with 5 min over run.
The fitter says he doesn't know and has asked vailant to attend at my cost.
Help appreciated. I am an electrician but my heating side is limited.
Ideas most welcome.

Thanks

 

[123]

Is the boiler firing without being called to?
It sounds like he has left the link in on the 24v RT which is a common mistake.

 

[Edward67]

Is the boiler firing without being called to?
It sounds like he has left the link in on the 24v RT which is a common mistake.

Hi thanks for reply.

The link has been removed and the heating is working on programmer as you would expect.
The pump is even on if I disconnect the programmer because the L and RT cable in the boiler are fed to connectors behind programmer no to the programmer itself.

 

[Edward67]

Hi thanks for reply.

The link has been removed and the heating is working on programmer as you would expect.
The pump is even on if I disconnect the programmer because the L and RT cable in the boiler are fed to connectors behind programmer no to the programmer itself.

Is the boiler firing without being called to?
It sounds like he has left the link in on the 24v RT which is a common mistake.

 

[Edward67]

It all worked before boiler was fitted.

Thank you. For help.

 

[andyb]

If, as you say, the second cable in the live terminal goes to the pump, then of course the pump will run continuously.

 

[Edward67]

If, as you say, the second cable in the live terminal goes to the pump, then of course the pump will run continuously.

So how do I rectify as heating engineer doesn't know. The only boiler connections are live neutral earth and RT.
What is different between this boiler and old boiler. I never saw the connections on the old potterton. Would it of has a pump feed on it?

 

[andyb]

You'll have to work through the wiring Edward, trace it and make a drawing. Does the extra cable go to the pump or not? it should be easy to prove one way or another. Does it go to the room stat? if not where is the room stat cable? where's the junction box? You need to find all these things before you can find the problem.
If you do a simple schematic drawing of where all the conductors go, you'll be able to sort this.

 

[Deleted account]

So how do I rectify as heating engineer doesn't know. The only boiler connections are live neutral earth and RT.
What is different between this boiler and old boiler. I never saw the connections on the old potterton. Would it of has a pump feed on it?

really! The heating engineer doesn’t know.
he shouldn’t be a heating engineer then.

The Pump needs to be wired into the switched live and come on when heat is called for. Possibly there is somewhere in the boiler for a separate connection to allow over run, but impossible to diagnose from afar.

 

[123]

It all worked before boiler was fitted.

Thank you. For help.

The pump needs connected to the pump terminal block in the boiler, at present there is nothing connected to that block.

 

[Deleted account]

The pump needs connected to the pump terminal block in the boiler, at present there is nothing connected to that block.

Good eyes 123. I couldn’t see the pump terminal in boiler. Where is it?

 

[Avo Mk8]

Good eyes 123. I couldn’t see the pump terminal in boiler. Where is it?

X14 - it's hiding under the mains cables, obscured by the brown & blue wires.

 

[Deleted account]

X14 - it's hiding under the mains cables, obscured by the brown & blue wires.

Wow good spot. Couldn’t see it even after you pointed it out. The wife had to point it out to me.
I still find It hard to believe the heating engineer didnt know how to do this.

 

[Avo Mk8]

 

[Edward67]

really! The heating engineer doesn’t know.
he shouldn’t be a heating engineer then.

The Pump needs to be wired into the switched live and come on when heat is called for. Possibly there is somewhere in the boiler for a separate connection to allow over run, but impossible to diagnose from afar.

Thanks for reply.
I think it needs a spdt timer relay fitting to control the pump unless the new boiler can be retrofitted.

 

[Deleted account]

Thanks for reply.
I think it needs a spdt timer relay fitting to control the pump unless the new boiler can be retrofitted.

The pump terminations have been identified in post 11,12 & 14. No retro should be needed. Your gas installer should know this. Consult him.

 

[brianmoooore]

Thanks for reply.
I think it needs a spdt timer relay fitting to control the pump unless the new boiler can be retrofitted.

It does need a timer relay to control the pump, and one, in some form or other, is already built into the boiler, but it won't do much unless the pump is actually connected to it!

 

[andyb]

123 did well to spot that, I couldn't see it, even after he said it was there. I do now.
What I would say is be carefull. The blue has some black tape on it so I doubt that it's a neutral.
My guess, and it's just a guess, it will need to be proved. Is that the extra cable is the switched feed for the heating and the pump live feed from the connections that 123 identified.

 

[Deleted account]

Going back to your original post. valiant are coming out at your cost.
seriously that engineer needs to pay for this not you. He should know better than us sparkies.

try the plumbing forum. They will slate the engineer for not knowing.

someone on here should give you a link to them.

 

[andyb]

Going back to your original post. valiant are coming out at your cost.
seriously that engineer needs to pay for this not you. He should know better than us sparkies.

try the plumbing forum. They will slate the engineer for not knowing.

someone on here should give you a link to them.

I agree, I'd get in touch and cancel, it can't be much.
You said that you think the extra brown is to the pump, then take it out of the live terminal and put it into the pump live, that will probally sort it.

 

[brianmoooore]

I think you ought to go through the whole of the wiring if it has been done by the heating "engineer".
There are apparently three two port valves in this system.
Each valve normally has a grey wire and an orange wire connected to a built in microswitch.
All three greys are connected together and are connected to permanent live.
All three orange wires are also connected together and go to the boiler switched live terminal.
A permanent live, from the same source as the grey wires are connected to, goes to the permanent live terminal of the boiler.
A neutral also goes to the boiler as well, of course.
The pump should connected, live and neutral, to the appropriate terminals in the boiler.
So, there should be a four core flex going to the boiler from the wiring box that the valves are connected to, and a three core flex coming from the boiler to the pump.

 

[andyb]

I think you ought to go through the whole of the wiring if it has been done by the heating "engineer".
There are apparently three two port valves in this system.
Each valve normally has a grey wire and an orange wire connected to a built in microswitch.
All three greys are connected together and are connected to permanent live.
All three orange wires are also connected together and go to the boiler switched live terminal.
A permanent live, from the same source as the grey wires are connected to, goes to the permanent live terminal of the boiler.
A neutral also goes to the boiler as well, of course.
The pump should connected, live and neutral, to the appropriate terminals in the boiler.
So, there should be a four core flex going to the boiler from the wiring box that the valves are connected to, and a three core flex coming from the boiler to the pump.

This is all correct Brian. However as it was just a boiler swap I'm guessing no other cables were touched, just the ones in the boiler. If this is true then the four conductors will be live, neutral, heat demand and pump live out.
That shouldn't be too hard to work out, and as he says the pump is on permantly that points to the extra brown being the pump and the blue with black tape being the switch feed to the boiler.

 

[123]

Going back to your original post. valiant are coming out at your cost.
seriously that engineer needs to pay for this not you. He should know better than us sparkies.

try the plumbing forum. They will slate the engineer for not knowing.

someone on here should give you a link to them.

Vaillant won't fix the issue either, it's nothing to do with the boiler.

Gas installers understanding heating wiring and controls? I wouldn't let most of them loose to connect a plug top.
I'd be concerned what else the boiler installer has done as the wago's in 1st pic look like they have just been installed as well.

 

[Strima]

That shouldn't be too hard to work out, and as he says the pump is on permantly that points to the extra brown being the pump and the blue with black tape being the switch feed to the boiler.

The one's in the roomstat termination?

TBH I'd rip the lot out and start again.

 

[andyb]

The one's in the roomstat termination?

TBH I'd rip the lot out and start again.

If I understand you, no, the one in the roomstst terminal is probally correct, the one in the live is probally for the boiler terminal.

 

[Strima]

If I understand you, no, the one in the roomstst terminal is probally correct, the one in the live is probally for the boiler terminal.

Looking at the flex I would have said both go to the roomstat but as the pump's running on who knows what's going on with the wiring...

 

[andyb]

Looking at the flex I would have said both go to the roomstat but as the pump's running on who knows what's going on with the wiring...

I doubt both go to the roomstat Strima, what would open the valve. Looks like the cable goes to the heating joint box where one is the return from the roomstat and the other goes to the pump. In fact if this was a straught swap with no messing with the wiring, that has to be the case.

 

[Strima]

I doubt both go to the roomstat Strima, what would open the valve. Looks like the cable goes to the heating joint box where one is the return from the roomstat and the other goes to the pump. In fact if this was a straught swap with no messing with the wiring, that has to be the case.

Quite possibly, but without looking we'll never know... ?

 

[Edward67]

X14 - it's hiding under the mains cables, obscured by the brown & blue wires.

Thanks all sorted now. Good spot and saved the installer the vaillant call out fee.

 

[Edward67]

By moving the the doubled up live to x14 the pump started operating normally. The RT does go to the room stat. As chased it through.
So thanks andyb you are correct.
The installer just missed the x14 because he usually installs worcester but couldn't get one in time.
Thanks for all replies and help.

 

[tony clark]

should have been easy if i remember rightly the suprima had a switch live a neutral and pump live
not much different from bosch any heating engineer worth his salt should be able to do this blindfolded

 

[Mike Johnson]

The installer was not correctly qualified/competent, you should get them back to move the doubled live to x14 to ensure you are covered by their insurance.

 

[brianmoooore]

Should be a 4C flex into the boiler and a 3C out of it to the pump from X14. As it is, it looks like the neutral to the pump could be disconnected during maintenance, leaving a live connected to it, which could be dangerous.

 

[Timbo]

Should be a 4C flex into the boiler and a 3C out of it to the pump from X14. As it is, it looks like the neutral to the pump could be disconnected during maintenance, leaving a live connected to it, which could be dangerous.

Brian, I think you're missing the fact the flexes obviously go back to a joint box of some sort as the boiler call signal and pump live are in the same flex.

 

[Deleted account]

Brian, I think you're missing the fact the flexes obviously go back to a joint box of some sort as the boiler call signal and pump live are in the same flex.

Timbo you are correct in the joint box( wiring centre) and the neutral and linked live feed will go to pump from there, but there really needs to be more conductirs in that boiler.

the pump terminations require live neutral and earth.
Just popping the pumps live Feed in the Termination strip Isn’t good enough.
All 3 terminations need filling. You can then take the fed direct to the pump or back via the wiring centre.

it may be that a link has been taken between both neutral and earth terminals, this if fine but I frown on it.

I know it would work functionally, but if your going to do a job do it right.