Problem with oil central heating boiler

[Frances]

Hello.

Does anyone have any ideas about what may be the problem with our boiler. It has recently started to cut out for no apparent reason, ie, the thermostat in the house is demanding more heat, the stat on the boiler itself shows that the temperature is low, but the boiler just does nothing, until we go out and press the red button on it to fire it up again.

We had it serviced - filters and plugs cleaned or replaced as needed, and as the problem is still continuing (in a fairly random manner) the plumber says that we need to replace the burner, which is going to be expensive...

I'm looking for a second opinion mainly because we're stuck in France, I don't understand oil boilers at all, and I'm not entirely sure that things aren't getting lost in translation between me and the plumber!

If anyone has any thoughts at all, I'd be grateful!

Thanks

Frances

[Grunff]

Could be a dirty photocell. This looks for light from the flame, and shuts the boiler down if there is none. They get sooted up.

[Jeremy]

I had a similar thing and it was a dirty photo cell. On my boiler (the only oil boiler I've ever played with) there is a grey electronic controller/ignition unit thing. This comes off with one screw and the photocell is obvious. I would have said that other things it could be are... Dodgy stat on the boiler (although it probably wouldn't fire up when you press the red button) Dodgy controller

I'm no expert though - just from my own experience

[Dave Liquorice]

Which red button? Our oil boiler has two...

One is on the burner (big box with blower inside and oil feed), this is the burner lockout. This lock out is triggered when the burner electronics detect a flame failure.

The other is on a control box with the boiler temperature thermostat. This is the boiler overheat cutout, triggered if the boiler gets to hot (approaching 100C).

[Frances]

The button is on the burner.

I'm also mulling over the other posts about a dirty photocell - would this be on the burner? There is nothing remotely high-tech about this boiler: apparently it is 20 years' old (though I hasten to add, it sat in a store room for most of that time, and has only been in use for 4 years)

Frances

[Grunff]

That's the burner reset - it's not detecting a flame.

Yes.

There's nothing remotely high-tech about photo cells :-)

[Dave Liquorice]

That is the burner lockout. It's not happy about something.

Yes, built in. It could well be the problem, though the soot is most likely to be on the window the photocell looks through to see if there is a flame.

Nor mine. Big lump of cast iron, some baffle plates and a blooming great flame thrower in the bottom... Hum, what does a boiler burner look like firing in the open?

[Frances]

It's jsut occurred to me that what I should be asking is - are photocells and/or the windows they look through designed to be cleaned (by people like me) or is this supporting the plumber's suggstion that I need a new burner unit?

How do I recognise the photocell, if it is something DIY-able? I'm not entirely ditzy - have done quite a lot of mechanical servicing, but am just completely unfamiliar with oil boilers!

Thanks.

[Dave Liquorice]

Never done it but provided you take care I can't see why you shouldn't have look. The burner is a moderate lump so when you unbolt and withdraw it don't drop it and damage the electrodes or nozzle. The blast tube should protect them a bit though.

The only link I could find on a quick google was:

news client will probably break that so cut 'n paste the bits...)

This has a drawing of a burner and the location of the photcell on it. The rest of that site covers lots of burners and Riello are very common.

Also found a UK site with photocells available for online ordering at

[Frances]

Thanks for this - I've had a look at the thermal-solution site, and there are some really good drawings there - now all I have to do is have another long look at the beast lurking in our boiler room, and decide which it most resembles!

[John]

SNIP

My server seems to have lost the beginning of this thread in ciderspace. Can I help (if you would like to repeat your original question and give details of your burner/boiler model)?

John