S-plan wiring

[CookyMan9999]

Hi,

I have wired a glow worm bolier up which has permanent live, and switch live in boiler....

At junction box in airing cupboard i wired pump into the switch live of the valves and is all working as expected.

About 6mnths after install the plumber has contacted and said that because i have not coonected pump to the L,N,CPC of plug that comes out of bottom of boiler this is causing boiler to overheat causing fault codes.

Is this plausable as i have not heard of this before and have done a fair few s-plan heatings now

Cheers

 

[ricicle]

Some boilers have pump run-on which allows excess heat to be pumped away from the boiler when firing had ceased.

 

[LearningSpark]

If the boiler has output terminals for the pump you must wire the pump via the boiler.
The way you have wired it means the pump will only come on when the valve sends the output to the boiler to fire. When the boiler cuts out when it reaches temperature the water still sitting in the heat exchanger will give out enough heat to cause the cut out in the boiler to operate. If you wire the pump via the pump output of the boiler the pump will continue to run after the boiler cuts out until the water temperature hsa dropped enough not to trigger the temp cut out on the boiler.

 

[londonboy]

Good replies above.

Be careful, not using the pump over run connection can cause the heat exchanger to over heat and crack, and the manufacturer won't cover it under their warranty because it's been incorrectly installed.