Alpha CD24...Intermittent red light (A)...&...

[Drew_]

Advice please...intermittent (as in not evey time or even every day) red light (A), have to reset. Also going cold for a moment after about 20-30 seconds of turning on the tap, it will then get to normal temperature again, it seems to be too hot at the start when this happens (temp sensor?). Also if I'm by the boiler at the kitchen sink (I know, sad eh?!)...the fan noise goes quiet when it goes cold, then slowly picks up to normal.
Wish I'd not bought an Alpha as it's had problems from new, but now the warranty has expired...

 

[Drew_]

I'd also like a reliable plumber to service it as it's now overdue since the original plumber and fitter of the system let me down...too many times...Worthing area. Tea/coffee always on offer!

 

[Drew_]

Additional problem...boiler not stopping central heating, even when switched to water only, getting red hot, have to turn off completely? Any ideas, don't hold out much hope of anyone having a clue as 2 months since original post and no responses...but I'll take the chance.

 

[PlumbBobBob]

the additional problem sounds like three port valve failing.

 

[Alpha man]

Additional problem...boiler not stopping central heating, even when switched to water only, getting red hot, have to turn off completely? Any ideas, don't hold out much hope of anyone having a clue as 2 months since original post and no responses...but I'll take the chance.

Sounds like the divertor valve has stuck open or the dhw flow switch.

 

[Drew_]

Thanks...will all be useful info when the plumber stands scratching his head no doubt! (no offense to any plumber who has ½ a clue!)

 

[tackleburger]

Flowswitches are problematic on these boilers and they cost nearly £30!! I don't think the flow switch is at fault though as the diverter valve would go to hot water mode if it was stuck in the on postion. That said It may well fire the boiler but it would not heat the house. Most likely the diverter valve or possibly a combination of both but usually only one fault at a time on a boiler. BTW the red A light flashing means your boiler has overheated B flashing on that boiler is usually the hot water sensor (I Think).

 

[Drew_]

Still having the problems listed, although it goes for some days of being fine...but I did have to cold shower the other morning as just couldn't get rid of red 'A' light.
Using reset does nothing - so I turn the boiler off for a few minutes, then sometimes it's ok when I turn it back on!
You may wonder why I still haven't called a plumber to fix it..?
I had some problems at a previous address with the boiler, after several visits by different plumbers (from the same company) all diagnosing it differently and carrying out work, I found myself the owner of a still broken boiler, but my pocket was now lighter by an amount that would have bought a new boiler! Hence my apprehension, so all input gratefully received, thanks.

 

[Alpha man]

Does the A light flash on-off or stay on continuously when the fault occurs?

 

[Drew_]

Hello...it flashes on & off, and I can only get rid of it, if I'm lucky, by turning the boiler off for a bit as the reset does nothing for this.

 

[Alpha man]

Sounds like the Air pressure switch is playing up, even though the MI state that the boiler has overheated!! Have been caught out once or twice on this myself!

 

[Drew_]

Thanks again.
I see I can buy the part for about £25 (akgas)...is it easy to fit or does it have to be done by a professional?

 

[Alpha man]

Drew,
Sorry I thought you had a CB24 not a CD24, the CD range DO NOT have a air pressure switch, (my bad for not reading your original post properly) Has your engineer removed and checked the DHW heat exchanger? / is the boiler noisy when in use for CH and HW and is the system water colour muddy?