In message .com, Neal
writes
On 28 Feb, 20:15, raden wrote:
In message .com, Neal
writesAll the answers have been useful, but I
vote this the most useful to
me who is not quite sure of what is going on.
From this I strongly suspect it is my PCB.
After the fan starts, I am hearing a sound more like a "chonk", which
suggest from the above the pilot valvle IS opening. But then no sparks
I also think I can smell a whiff of gas in the flue.

I think I have reached the limit of my knowledge, so I have a guy
coming this afternoon (name found in littlegreenbook.co.uk- wish me
luck)
I have told him I strongly the suspect the PCB, so he has agreed to
try and bring a re[placement with him...

I take it, you've seen my site

www.cetltd.com

--
geoff

Oddly enough, I just found your site from a link on the Fool.co.uk
site

Turns out it was the air pressure switch after all. It had stuck
A knock, and it worked again....untill yesterday.
Another knock then and it worked...Until this morning
This morning: the fan has packed in. I feel like the the dutch boy
with his thumb

So, I am planning to get a new boiler (old one is clearly dying)
But in the meantime (my friendly plumber is on holiday) I need a quick
fix (2 small children....)
So Geoff, expect a call in the morning for a ("new") fan

If the APS is knackered, it will not bring on the fan

It needs a good short circuit between the normally closed and common on
the APS to allow the fan to work

I'm not sure that your "clearly dying" diagnosis is necessarily anywhere
close to the mark

I'm not sure of the price of an APS, but added to £75 ++ for a fan AND
pcb would be far less than the cost of replacing the boiler at £1500 or
more


--
geoff