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Mend Worcester Central Heating Boiler Ignition

Central heating boiler ignition lockout?

I have an ongoing problem with my boiler, a Worcester Bosch 28Cdi. From time to time the central heating light (red) flashes slowly indicating, according to the manual, an ignition lockout.

I have a maintenance and service contract with a company in the North-West. Perhaps I should not include their name. Over the last couple of years they have changed several components: recently, the gas valve, the diverter diaphragm which was perished (although this was for a different problem), the pressure gauge, and new seals to cure a water leak; a year or two ago they also replaced the fan and (I think) the PCB.

The problem seems to go away for periods of weeks or months, but then returns. Recently, it has happened on 14th, 20th, 23rd and 25th October (twice), then 4th, 26th, 28th and 29th December, then yesterday evening (twice) and this evening. As you can see, it seems to occur in phases!

I last contacted the company with which I have the contract on 29th December and they agreed to come out on the following Friday. On that day, however, the engineer who usually comes telephoned to cancel the appointment, saying that he can't do anything else!

I agree that this firm has done quite a lot of work on the boiler already and, financially, I suppose am probably 'well ahead'! However, I really don't know what to do now. At the moment, whenever the ignition lockout occurs, I go outside to the garage (in the freezing cold!) and press the red re-set button for five seconds. The boiler always then ignites, so at least I still have heating and hot water (eventually).

Does anyone have any ideas of where the problem might lie? If I can suggest this to the engineer, I may be able to persuade him to come out and try again.

John Robinson
January 2009

Worcester Heating, Home Heating Systems Central Heating Boiler Ignition

Sounds like suspect gas pressure. I am an engineer and such sporadic faults don't occur without external influence. It could be temperature related but I'm willing to bet that when all the boilers in the street fire up the pressure is too low. I have a Worcester Greenstar 18Ri and it ignition lockouts randomly in the morning. I swapped the whole boiler. Same thing. It turned out to be the gas meter regulator not keeping up the house pressure properly when the mains pressure dropped during high demand.

Tony Arkinstall
November 2016

The pilot on combi boiler went off by itself and refused to ignite

John Lee
October 2009

Although the problem has not re-occurred since the one episode in August, I did try to arrange for a local engineer to come and look.

One of those recommended by W-B stated that he only deals with boilers he has installed himself; another, who said he had a good idea what the problem was (something to do with the fan switch) said he would get back to me and never did. Why do boiler engineers do this?

I also contacted Worcester-Bosch, who offered to send one of their own engineers at a charge of £210, which would include parts, labour and VAT (unless the engineer found something 'more significant'). Unfortunately, W-B will not touch the flue and, of course, there is no guarantee that whatever they do will sort the problem - I was sure I read somewhere that they will keep trying until the problem is solved, at a fixed price. That would have been a 'good deal', but the service on offer seems a bit 'hit and miss'.

As I said, the problem has not re-occurred since August. When it does, I'll have to decide on some course of action.

If, as BB suggests, it is the electrode lead, is this something I could tackle myself? As I said, local engineers don't seem particularly interested!

John Robinson
September 2009

Thanks for your answers.

Fortunately, the problem hasn't re-occurred since May... until the other day, that is! It does seem to happen more in cooler weather, so I wonder if that could be something to do with the problem.

I should also mention that the boiler is situated in an unheated lean-to garage.

John Robinson
August 2009

Alas, I've only just seen this query. However, I strongly suspect you will have replaced your ignition electrode by now and, in so doing, parted with yet more of the contents of your wallet.

The electrical leads to such electrodes have an inherent tendency for 'tracking' i.e. sparking elsewhere than where required, after residing for some time in one's dear old hot boiler.

The tendency for tracking in this situation is basically due to the high voltage, passed through such leads when attempting ignition, causing the current to take the easiest path possible and resulting in ignition lockout whenever the gas fails to ignite within the designed 'time slot'.
Easier paths are presented in the leads when ch boiler designers, in their wisdom, under-design in terms of the heat and insulation specs for such leads.

This design principal, no doubt, ensures a secure work load for 'service engineers' and steady profit margins for boiler manufacturers.
But we, ignorant, consumers don't mind that. And, as it is for so many things in this life, it wouldn't matter if we did.
Would it?

Billy Bigelow
July 2009

companies should not make such difficult things , every thing should be easy opreating and easy understandable simple cheep affordable. boiler is not a very complecated machine so why the compines making it comlecated and i cant say nothing with out looking that boiler

ahmad
April 2009