Boiler - very broken or meerly broken?

[finpos]

I have a vokera boiler, about 10 years old, with a pilot light. Recently the fan has started to sound very nasty, and I'm at the point of getting a man in to fix it.

But the squeaking has alerted me to the fact that the fan runs ALL the time - at full speed when there is a call for heat and half speed when no call for heat. Is this right? Or has a dodgy controller conspired to knackerate the fan?

Just a bit confused - I'd accept that maybe the pilot requires the fan to run all the time, but I can turn off the fan by switching the controls off - and the pilot stays on. I suspect there should be some form of timer on the half speed fan running?

cheers.

finpos.

 

[DarkInferno]

without the model I wouldn't know if it was supposed to be running 24/7 or not, however I suspect it is supposed to run half speed for the pilot as you also thought.

The pilot is there because heat on the thermocouple holds open the gas valve, the fan is spinning because it receives electricity. If you turn off the electricity its not hard to see why the pilot will stay and the fan will stop, if you turn the gas off it won't stop the fan

 

[hotncold]

Hi
I used to have a Vokera boiler and the fan doesn't last that long really, i changed a couple within about six yrs. If it sound noisy the bearings are knackered.
It is correct that the fan runs on half speed when boiler not on. If the fan was off
you would find that the water in the boiler would be get too hot and when it switched on you would get a nasty banging noise.

 

[croydoncorgi]

ALL (I think) boilers with fan flues and permanent pilots run the fan at low speed when the boiler is NOT firing. This is to ventilate the pilot and cool the heat exchanger (which otherwise would get quite hot from the pilot flame). (Another good reason for electronic ignition.)

 

[DP]

Almost certain the boiler is a Flowmatic 20 80. A boiler built like a brick outhouse. Is it any wonder that the boiler is not behaving as it should when the boiler is unlikely to have been serviced AS PER THE MAKERS INSTRUCTIONS.

I service/ repair these boiler regularly. This is one of the very few boilers that will take a fair amount of abuse and still limp along.

I am in Glasgow and can offer my services, else get someone who is familiar with Flowmatic operate sequence and is able to diagnose the defect.

 

[PEDANTICVINDICTIVEMAN]

Fan dunner run on low all the time on the Worcesters I have been fitting, maybe becasue they dont have pilots.

 

[tangellion]

I have the same problem with my vokera EXCELL 80SP. I believe the flow switch diaphragm may be the culprit. I believe this controls the fan speed when HW is demanded, it should slow down the fan when hot water is not being demanded but after ten years it probably needs replacing as it is only rubber and can get stuck or holed. Would like confirmation of this though before I buy the replacement.

 

[ollski]

Start a new thread with your problem...gets very confusing otherwise especially after 2 and a half years.

 

[DP]

Not on Excel boiler tangellion. At least I have not come across one (and I repair plenty of these babies installed by the truckload hereabouts)

 

[gas4you]

ALL (I think) boilers with fan flues and permanent pilots run the fan at low speed when the boiler is NOT firing. This is to ventilate the pilot and cool the heat exchanger (which otherwise would get quite hot from the pilot flame). (Another good reason for electronic ignition.)

Pretty certain you are correct on the Vokera, especially if it is the Excell. New fan is very easy and quick to replace and usually parts are readily available.