Urgent. No heat as boiler thrown a wobler.

[ray99]

Hi guys. Need your help with this. Appreciate I probably need to get professional help in though.
Came home early hours from a 10 day holiday and there is no action from the boiler. Left the heating on with the thermostat turned down a bit while away.
Glow worm Ultimate 40FF Installed in 2000 so getting on a bit.

There is a noise like an old door bell buzzer constantly regardless of whether the heating or hot water controls are on or not coming from the PCB assembly. Only way to stop the noise is to switch off the mains.
I have had a look at the neon lights and none are on. Number 1 is power supply or PCB fuse but the noise would suggest power supply is ok. Trying to activate the heating does operate the pump upstairs in the airing cupboard. Will have a look at the fuses anyway while I wait for replies.

Thanks. ( 26 degrees in Tenerife yesterday and -2 when we landed so frozen and desperate. )

 

[kidgreen61]

Almost certainly fan seized, you will need an RGI to change it for you.

 

[ray99]

Replaced the fan (at the top) last year as it was starting to seize but can easily check it again.
Just done a Google on it and looks like it is a relay on the PCB that has failed.

 

[oilboffin]

If you know what the fault is why ask on here my friend.Bob

 

[ray99]

I don't know what the fault is hence I am asking for advice. Did a Google after posting the question which has suggested the PCB is at fault.

 

[Madrab]

Unfortunately you need an RGI is to do some testing at the board to see if the board or another component is causing it. Time for temps

 

[dilalio]

I don't know what the fault is hence I am asking for advice. Did a Google after posting the question which has suggested the PCB is at fault.

Hey, that's understandable fella... coming back from 26 degrees to -2, I'd be reaching out in every direction too! Sh!t: I'd call NASA

 

[Agile]

It may be the smoothing capacitor on the PCB has eventually failed.

Easy enough to change it if it is at fault for someone with a little experience.

Tony

 

[AGAS]

if it is the capacitor ??? if you have a suitable multimeter , test it to the value written on the cap itself , if it is the cap you will normally find it has swelled .
if it is the relay you need a new pcb , well depends if your competent with electronics .

 

[Agile]

A 100 Hertz hum from relays usually indicates a failed smoothing capacitor.

A quick test is to temporarily connect a similar cap across the DC supply and see if that cures the problem.

Tony

 

[ray99]

Pushed for time and desperate so bought a pcb from ebay for £20 on Sunday night, fitted it tonight and we now have heat. When I get time I will bring my fluke meter home from work and check out the actual fault on the old pcb out of interest. As the boiler is 16 years old going to look into getting a replacement sooner rather than later. Thanks for the info on capacitors, will check them out on the old unit.

 

[Agile]

Quicker to just buy a new smoothing cap for about £1.22 and replace it.