Keston celsius 25 failing to light

The error indication you describe isn't in my manual. Look at the fault finding section in your manual, and try to match it against a description.

Mine often fails to light first time (or rather lights and immediately goes out) when it hasn't been used for some days, but retries a minute later and relights either second or third time. It's done this from new. I've never been there when it's happened so I'm not sure if there is any other obvious sign. I only know it happens because I log the boiler's burner activity in the computer which controls it...

May 31 07:57:30 Temperature - Downstairs 17.5 May 31 07:57:31 Output Downstairs Heating Demand ON May 31 07:57:49 Input Boiler Burner ON May 31 07:57:51 Input Boiler Burner OFF May 31 07:58:21 Input Boiler Burner ON May 31 07:58:22 Input Boiler Burner OFF May 31 07:58:52 Input Boiler Burner ON May 31 08:18:51 Temperature - Downstairs 18.0 May 31 08:18:53 Output Downstairs Heating Demand OFF May 31 08:18:53 Input Boiler Burner OFF

Ours did that last year, it turned out to be a blocked filter on the gas inlet (just before the solenoid valve inside the boiler).

The valve opens in two stages, the first stage is a for a small pilot flame lit by the spark from the igniter, when the boiler senses that the pilot flame is alight it opens the main valve and the boiler lights.

The blocked filter was letting enough gas through to light the pilot flame but, as soon as the main valve opened, the gas pressure after the filter dropped so low that, although the main burner did sometimes light (making the "whumph" sound), it ran out of gas and went out again.

The boiler was trying to light 4 times (I think) and then locking out and giving various different errors, making the fault hard to diagnose.

The filter was blocked with very fine carbon flakes which are, apparently, added to the gas to seal any minor leaks in the gas main.

Hope this helps, Martin

This can be crud on the sensing contacts. This can retain moisture. The repeated tries dried this out as the fans dries it uop. Clean the probes.

In article , Andrew Gabriel writes

No... it isn't in my "user" manual either. According to my manual it should be associated with one of the 1-4 lights coming on. But no other lights are on (except the mains light), just the red light doing 2 flashes.

However the "install" manual in sec 4.10 says "If the red lockout LED flashes twice every 2 seconds this means that the boiler has failed to light. Turn off the user control knob off (fully anticlockwise) and wait

but the user guide does not say this.

I happened to be standing by it when it did it last time, and the red light started after it had tried & failed to ignite 5 times.

Mine has always been the same, and it only fails to light when it hasn't been on for some time.

Makes good sense, mine behaved like this when the mixture was set a bit lean (c/f blocked gas filter) and sorted itself out when it was set up with a CO analyser that I hired - 50quid for the day tho.

In article , fred writes

ps: don't try to reset the gap on the igniter electrode on anything but a new one as they become hard/brittle with use & will break (bitter experience).

In article , fred writes

I think I'll get the guy who installed it to come and check it, he did have a CO analyser. It only does it occasionally.

So true :(

Keston are running a summer service offer: £70+VAT fixed price including any necessary parts: 020 8462 0262. Your guy may do better than this of course.

In message on Mon, 27 Jun 2005, Tim Mitchell wrote

Exactly the same here. Worked OK since May 2004 and then on Saturday failed to ignite. Same indication. Tried off/on several times and made note to contact service agent. Then on Sunday morning it started OK and it's been fine since then.

This error code is not recorded in the manual but I recall from previously that it's an ignition failure irrespective of there being no diagnostics lit.

Incidentally, since it's been discussed before; I've just received the Summer 2005 service "special offer" - £70+VAT all inclusive. It's no good to me because I'm on a service contract now but others might be interested since Keston don't always seem to let all end-users know.

Regards, Colin

Is that valid anywhere in the country, cos I'm oop north. (Not very north, but north enough for Londoners).

Londoners think England is north.

Not on mine (it daren't 8-;). However I suspect that there make be a loose connection on the ignition - not enough to stop the spark but enough to disrupt the flame sensing. Or some sort of crud on the electrode.

That happened on C40 install of mine, due to sulphide particles in gas the supply.

According to the letter it's a 'special offer' and you have to phone and quote your secret number. So by disclosing it I'm perhaps liable to be dropped in a vat of condensate .

It could be a regional thing depending on where their own engineers are located and/or there are enough boilers within a finite geographical area - they note your details then get in touch when the engineer wants to come, often within an hour or two, so I suspect they save up the bookings until there are a number of customers close together.

Doubt there will be any close to me, I am in Ideal Boilers territory (factory just down the road so all the local installers use them!)

My local installer is quoting 39 quid to service it so I will probably see how they do with it.

Keston are in Bromley so crossing the Thames to Twickenham is probably an adventure