worcester 28i

[Hobo128]

Was called out to this boiler the other night, no hot water no central heating, boiler not firing. This is the old 28i with the grey front (non condensing)

Anyway, took front casing off and the fan looked like it was struggling to spin, gently blew down the air pressure switch and ignition started. Put tube back on air pressure switch and after a little while the fan began to spin a boiler fired up. I had it down to the fan bearings are maybe on there wag out. Checked resistance on fan, got about 50 ohms, not sure if this is right.

I want to know if I'm know the right track looking at the fan.
What resistance the fan should be.
And what is the operating sequence of this boiler.

Cheers

Hobo

 

[arran197]

Did you hear anything clicking noises or has the customer heard any clicking noises? These boilers are common for pcb failure. The part that fails is the relay for the fan. So the fan won't run. Also, as can cause issues, there's a simple way of testing it detailed in the instructions. Which you can get from the Worcester website.

 

[bewsh]

if you're getting the correct voltage at the fan, it wont be a pcb issue.

have you tried cleaning and lubricating the fan?
checked flue for restrictions?

 

[kris]

I'd say the fan . By blowing down tube you've bypassed the fan and triggered the ignition sequence so I'd be looking at the fan motor or blades needing a little lub lol. Like arran said it's possible the relay isn't switching.

 

[Whyme]

This is going to sound really old fashioned, Rather than test the fan for ohms etc. If it doesn't spin very freely and keep spinning by flicking it with your finger for a while the bearing closest to the fan casing has dried out. Ya can lube them but they dont last long before needing more..

 

[arran197]

If you check to see if you are actually getting voltage to the fan that would help you eliminate the power supply going to it. If there's no power going to it then it could be a pcb or aps issue.