Potterton Boiler Control 407676 resistor value

28 Apr 2012
Reaction score
United Kingdom

Can anyone help me identify the green component (and associated values) on the control board of the Potterton 407676 marked R11 please?

I suspect it is a resistor but it has no markings hence my problem!

I've circled it on the image below.

Any help greatly appreciated as I'm missing my hot water and central heating!
Sponsored Links
Thanks for the "advice" - I'm sure it's because you care :D

It was a gas engineer that diagnosed and removed the circuit this morning.

The new PCB has been ordered by the engineer and will arrive and be fitted on Tuesday, but we were looking for a temporary solution until the new part arrived hence posting on the forum.

We aren't looking to "modify" the circuit merely replace the failed component(s).
U might be better off asking the sparkys ?? generally resistors on any pcbs have colour banding on them like the other ones on that board, this banding is a code eg each band signifies certain imfo , which than allows u to work out a given resistance of said resistor (afaik)

Assuming u have the code of course :)
Sponsored Links
A green 'vitreous' wire wound resistor like the one you have ringed would normally have the resistance written on it e.g. 12R or 1R5.

It looks to me like the very large 'metal film' resistor to the right of the rectangular metal thing has blown as well. It appears to have a brown crack through it which is typical of the way they would burn out.

I would suggest there are probably other components on there or even off the board itself that have caused the resistors to fail.

Hi I have a problem with the same board can someone please identify a replacement HT transformer at the top right of this board please
It is questionable that it is correct for a DIYer to attempt to repair a boiler control PCB as the boiler relies on the PCB for safe operation.

Most of the EHT transformers used on boilers are similar although pin outs may vary slightly.

Most are powered by discharging a capacitor charged to about 350v into the primary.

But why do you think that it has failed?

The winding has burnt out and I have no continuity through the primary winding

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links