Ideal Combi - DHW but no CH

[McrRed]

Hi.
I've tried the FAQs and searching but can't find any answers.

My Ideal Boxer C24 started going out in the high winds last week (I assumed the draught was affecting some internal sensor).

Since then the problem has got worse (the timing perhaps coincidental?)

The CH is supplied initially then after about 10 seconds the flame goes out...the pump keeps running. After 20 mins or so, the boiler shuts down with a red LED warning light.
If I turn off the boiler then back on, the cycle repeats itself.

If I call for DHW the boiler supplies it without fault.

I seem to remember exchanging the diverter assembly a few years ago...could this be the problem? There are salty deposits on the union nuts that connect the diverter to the pipework could it be seized inside? Can it be cleaned? (I think it has an oil cap or something - it doesn't use microswitches).


Many thank for any ideas or solutions offered!

 

[McrRed]

Wow. Just looked at possible replacement diverter costs: AllSpares have them for £60 but sold out. Ebay charge £150 and HRPC (where I got the last one for £70) are charging £300 plus vat!!

Please let it be the thermocouple that's at fault...I've got a freezing house with kids that are going to get no presents from Santa this year!

Hey, guys, look what Father Christmas has brought you a new diverter valve!


Just like the olden days...

 

[McrRed]

Ok. So now it's getting interesting...

I took off the temperature sensor for the central heating and the boiler fired, delivered good temperature to the radiators for the first time in ages...then promptly cut out.

Does this mean it's the temperature sensor/thermistor or overheat thermostat that could be at fault?

Please guys, I'm tearing my hair out here!

 

[bhm1712]

get a professional in to have a look, if it still cut out i would say its not the temp sensor...

 

[McrRed]

Thanks bhm, I may have to do just that.

Though this forum IS called DIYnot.com I thought there might be someone out there to give me a couple of pointers.

I've just realised that no matter whether on CH and cutting out or DHW the temperature gauge is not working. Does this ring any bells?

 

[Agile]

The bell it rings here is that its a combustion/gas issue and thats something that we dont give advice for DIY repairs.

Get a competent gas registered engineer! Not such a difficult problem to diagnose.

Tony

 

[McrRed]

Ouch!

Thanks Agile...I guess you've got to be careful...

...but, in my case, the combustion is fine there is either a sensing issue where the boiler is being told to turn off too soon or the diverter is playing up which I now suspect isn't the case as with the thermistor off it was giving full attention to heating the CH.

I've been coming in here for years and it was advice from you guys that got me through previous boiler failures (including the last time the thermistor went and the time before that when the diverter failed). Usually a hint or clue is enough to avoid costly mistakes or at least ask the gas engineer the right questions. Also. there are enough stories on the forum of qualified gas engineers getting called in that don't have a clue...if you think about how hard it is to get your car serviced by someone you trust you can see what it's like for us guys (and bad DIY car repair has no less deadly consequences than bad repairs to boilers).

I'll take yours and bhm's advice -but I still would like to know(!)

Thanks for your time anyway... now where's that yellow pages?

 

[Agile]

I always recommend calling a competent engineer!

Personal recomendation is the best way and even them only when its based on a successful diagnosis of a complex fault.

Someone who has solved a problem which has foxed several engineers from British Gas could well fit the bill.

Yellow Pages is only a guide and considerable questioning might be needed to know if someone could possibly be suitable. Those who are confident to offer a no-fix no-fee could be a starting poinht.

Tony