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.