Potterton Netaheat - No pilot light

[jamieO]

Not sure if this is an age old problem you guys will laugh at:!!

Here goes though. I have a Potterton Netaheat wall mounted boiler. Probably about 20 years old. When I switch on the CH/HW, the fan within the boiler starts as normal but the pilot light (seen through the little window) doesn't light. If you look very very closely, you can see an intermittent spark within but thats it, nothing else.

Does anyone have any idea of the problem or how easy it is to fix. Alternatively, is it that complicated thats its best to get a professional in (in which case, any idea of likely costs?)

Many thanks

 

[ollski]

Last time it got a service?

 

[jamieO]

About 3 months ago. Why could it be coked up or something?

 

[hartnellg]

Hi,

I had a problem with a Netaheat that was about 20 years old and eventually got it fixed - see the post 'boiler not coming on' and I've repeated it here. It may not be the same thing, but the checks are easy:

1) the actual problem was the relay which plugs into the PCB - relays have a finite lifetime and after about 20 years of operations, this relay had reached it. You can buy this relay from most electronic component distributors - it's an industry standard relay - 3PCO 230VAC
E.g. www.cpc.co.uk, part number SW0153366 - cost about £6 +VAT
(or about £35 +VAT if you buy it through a plumbers supplies ???)

2) the engineer replaced the PCB, but this was unnecessary on the Potterton Netaheat MkII 10-16. The pcb on this model has no active components and the only thing that can go wrong are dry joints. The component and assembly cost of this item is under £5, but the insurance company was charged something like £140 + VAT. Someone is making a HUGE profit here - anyone know why this should be ?

3) There's a functional/electronic wiring diagram in the boiler documentation which shows where/how the pressure switch, boiler thermostat and relay operate - I wish I'd spotted this before getting someone out, it would have saved me a lot

Have a look at the functional diagram in the docs - as far as I can remember the relay uses the the 3 poles to:
a) hold itself closed
b) provide a feed to the spark igniter
c) open the gas valve

The relay is opened by either the pressure switch or the boiler thermostat
It might be as simple as replacing the relay, and it's very cheap and easy to do

Hope that helps

Geoff