Cold Boilers

[bugshaw]

The boiler has a habit of, once it has cut out because of the timer and/or thermostat and/or any other reason, not self-starting when the timer/thermostat triggers it on, so one has to press the reset manually. The lights come on on the timer quite happily, but the boiler doesn't fire up.

It has gone from doing this occasionally, to doing it most days, and today so far it has done it three times. By the time I notice (when my fingers stop working happily) the temperature has usually fallen to around 15-16 C.

I threw a lot of money at it when it was happening to the tenants this spring, and it hasn't been resolved satisfactorily. It's a five-year-old boiler in a five-year-old house, and passed a landlord gas safety check in September. I don't know what to do about it other than throw even more money at the sort of people who couldn't find anything wrong with it last time. I don't want to spend the winter with central heating/hot water that effectively runs on a 2-hour manual boost setting only.

Comments

[james-r.livejournal.com]

Do you have the make / model of the boiler? You're likely to be able to find the service manual online, which should have a debugging chart, which will likely tell you the problem is one of the following things that try to happen not doing, or not doing sufficiently:

Circulating pump starting
Flow switch activating
Flue fan starting
Flue flow sensor
Gas regulator
Gas ignitor
Ignition detection electrodes

Each thing usually goes in sequence, you can probably figure
out where it's going wrong by listening to it :) I can with
mine anyway..

[bugshaw.livejournal.com]

Mmm, and I could test it by switching it off at the timer and switching it on again. I think the tenants went through this at some length, certainly the manual that came with it has been annotated. That will be my fun way to spend the evening.

It does come on properly sometimes. This morning, for example :-)

[techiebabe.livejournal.com]

Mine has started to make a slight bang / knock noise as it kicks in "properly".

Can you diagnose it from that? :)

Last time it didn't work, the cause was mice eating the wiring(!)

[james-r.livejournal.com]

At the point it ignites?

Could be too high flow during the pre-ignition phase, causing a mini explosion in the combustion chamber...

Fun :)