Boiler Wiring - do I need SwL and Pump live?

[D_Hailsham]

I have a 3-port valve, a pump hot water storage tank, a normal boiler. Is this a Y-Plan setup?

As you have 5 wires on the valve, then Yes it is a Y Plan.

I have the wiring diagram for a Y-Plan and it all looks straight forward except that I have two additional wires from the boiler that aren't on the wiring diagram. The boiler is a Potterton Suprima 30-100. I took the from off of it and the two wires are coming from Swl (Switched live) and Pump Live. My diagram simply has Live/Neutral/Earth going to the boiler. Do I need to use the SwL and Pump Live wires or can I just use the LNE wires?

You need both Pump live and switched Live.

Here is the wiring diagram for your system.

View media item 13167

 

[wazzag]

Thanks DH!
My wiring matches the diagram exactly - and i've double checked everything.

When I switch power on the controller seems fine, I set the stats to high (demanding CH/HW) and put the controller into "Constantly on" mode for both HW/CH.

Nothing - boiler power light is off, no pump.

I've checked voltage across terminals 1 and 2 and it's only around 24V. I've checked the voltage across these terminals with the programmer off and it's 240v.

Please help!!

 

[londonboy]

Measure between L and E at the boiler and see if you have 240.

Then turn on heating/hot water and turn stat up above click and measure between SL and E at boiler. You should have 240 which indicates call for heat

 

[wazzag]

Measure between L and E at the boiler and see if you have 240.

Then turn on heating/hot water and turn stat up above click and measure between SL and E at boiler. You should have 240 which indicates call for heat

240v between L & E - yes
240v between SL and E - yes

 

[londonboy]

I must admit I don't work on potterton but is there an on/off switch on the front? Or a reset button.

Also measure between L and N (look for 240 again)
And Sl and N (240)
That will prove the neutral conductors continuity.

If all the above is correct then one of the gas engineers will have to advise further (im an electrician)

 

[gas4you]

Check the 2 amp fuse on the pcb. It's in a little 'black tube' with a screw on top.

A faulty pump can blow this as well.

 

[londonboy]

I've just looked at the book (HE version, unsure what yours is) try turning temp dial down for a few seconds and then back up to maximum.
Could possibly clear a fault.

Yes and also check internal fuse.

 

[wazzag]

ok,

Fuse checked and is ok.

there's only 30V between N and L
there's 0v between N and SL

There's no light at all on the boiler.

 

[londonboy]

But you have 240 L to E right??
And 240 SL to E yeh??

If yes then there is a neutral gone amiss somewhere, in wiring centre or spur maybe?

 

[namsag]

What was it that simond said on page 1

 

[londonboy]

I've only just seen that. Take some pics of programmer and wiring terminals, and upload.

namsag I just looked on that controller link but that has 10 terminals.
The op said his had 6?

bloody hell....... call an electrician! its easier!!

 

[wazzag]

Just to clarify:

The programmer is a Sunvic 20 XLS whith is a 6 terminal "standard" programmer.

12 terminal block of which 9 (including the pump overrun wiring) terminals are being used is located in the airing cupboard containing the cylinder, pump, 3-port (5 wire) valve.

No lights on the boiler at all, 240v between E and L, 240v between E and SL. 30V between N and L, 0v between N and SL.

 

[namsag]

edit

 

[simond]

As said above you are missing the neutral. Bearing in mind it would have been there before, one has to wonder where it is currently terminated.

Very basic stuff; you should get your work checked by a competent person because what you have put in may unwittingly be dangerous now or in the future.

To quote an oft used phrase, 'you don't know what you don't know'.

Are you using a four core for the cylinder thermostat?

 

[D_Hailsham]

My wiring matches the diagram exactly - and i've double checked everything.

Including the pump overrun alterations in the small diagram, I hope!

When I switch power on the controller seems fine

Proves it is getting power!

Nothing - boiler power light is off, no pump.

The boiler L, N and E connctions must come from terminals 1, 2 and 3.

I've checked voltage across terminals 1 and 2 and it's only around 24V. I've checked the voltage across these terminals with the programmer off and it's 240v.

Could be backfeed.

Here is Honeywell's test routine, hope you can read them OK. If you have wired up according to Honeywells diagra, the terminal numbers will be the same. Programmer, Room stat and cylinder stat terminals may be different if you do not have Honeywell components, but should be easy to identify.

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