Central heating wiring

[adwt2004]

hi, hope someone can help

I have a problem whereby my central heating pump never stops running. I've done some research and found out that my boiler has been wired up as if it has a pump over run facility where the pumps runs afterwards to cool the boiler down. My boiler an Ideal icos doesn't have this facility so when it was installed it was done incorrectly.

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• adwt2004
• 15 Oct 2009
• 1

I have a Y plan system and links 4, 5, 6 have been cut to configure as per image above. I believe I need to re-link 6 because it shouldn't have been cut but not sure of the cables going into the wiring centre. see below

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• adwt2004
• 12 Oct 2009
• 3

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• adwt2004
• 15 Oct 2009
• 1

Do I remove the switch live and pump live or leave in situ?

If someone could advise I'd be greatful.

 

[kevplumb]

post it in plumbing

afore you get big mouth and his rule book

 

[adwt2004]

I did mate and no one seems to know about it unfortunately

 

[electronicsuk]

Presumably, re-instating link 6 should disable any pump overrun, although it's likely that all this does is link the pump L to boiler S/L. As you say the pump currently runs all the time, and all connections to the boiler appear to have been wired in, the installer has probably linked the boiler pump L to permanent L at the boiler. If you reconnect link 6 then you will also need to disconnect and make safe the boiler P/L connection at the wiring centre, otherwise it will still run all the time.

As the links can only really be properly re-attached using a soldering iron, it may be easier for you to simply remove the wire from the pump L terminal and move it to the boiler S/L connection at the wiring centre, so you will then have two wires in the boiler S/L terminal. This should have the desired effect of making the pump run only when the system is calling for heat.

 

[D_Hailsham]

I assume the pump is external to the boiler.

Remake Link L6

Connect the pump to the pump terminals in the wiring centre.
Remove the wire connected to boiler P/L in wiring centre and disconnect the other end.
Leave the other boiler connections.

 

[adwt2004]

Ok, the pump is already connected to the pump terminals in the wiring centre. LNE.

I'll look at remaking link 6 and removing the boiler pump live. I'm also going to take a look at electronicsuk's post as that seems very clever too.

Thanks guys for your help, time to play with it i guess

 

[bengasman]

If you are sure your boiler does not need an overrun, why don't you connect the pump over the boiler connections in the wiring centre? Lot easier than trying to alter it.

 

[adwt2004]

so instead of having the pump wired into the pump section on the wiring centre where do i connect the wires with regards to my first image? (just in the L N and E of the actual boiler section so two cables in each terminal?)

Interesting idea and something i didn't think of

 

[bengasman]

Just combine pump and boiler wires, it's probably how the boiler diagram does it.

 

[gavinda]

just throwing in my 2p. dump the pcb wiring centre and rewire it in a proper wiring centre. more reliable and easier to trace .

 

[Agile]

Welcome back Gasvinder.

I am surprised to hear that the Icos does not have a pump over run facility whereas the combi versions did.

Tony

 

[gavinda]

hi agile keep getting distracted by other forums .


methinks theres quite a few boilers without pump overruns these days. potterton crap comes to mind. weve been fitting a lot of overrun timers due to this issue.

 

[electronicsuk]

so instead of having the pump wired into the pump section on the wiring centre where do i connect the wires with regards to my first image? (just in the L N and E of the actual boiler section so two cables in each terminal?)

Interesting idea and something i didn't think of

Just follow the instructions as per my first post. There's no need to touch the live or earth connections to the pump as they will all be tied together in the wiring centre. If you don't want to remake link 6 then all you need to do is move pump L to boiler S/L, no other work required.