Halstead Ace High - DHW Problem

[howarthcd]

Hi All

I've started having issues with my Halstead Ace High and I was hoping that someone with greater boiler knowledge than I might be able to help me pinpoint the fault.

After running DHW for approx 5 mins the burner cuts-out, the water runs cold and then the burner re-lights within 10s - 30s of cutting out. Whilst this happens the 'Hot Water' LED on the control panel remains on. This cycle then repeats, but with the burner cutting out at intervals ranging between 1 and 3 minutes.

Further Info:

1. The resistance of each of the DHW and CH thermistors is just over 10Kohms at room temperature.
2. The diverter valve's diaphragm was replaced ~6 months ago as it had split - as far as I am aware the new part is still fine.
3. The problem seems to be worse in windy weather - a gust of wind often makes the burner cut out.
4. CH appears to be fine, although suffering from the same issue as DHW in windy weather.
5. Water pressure is high.
6. Water is soft.
7. Boiler is about 6 years old and hasn't been serviced for at least 2 years.

Any pointers would be greatly appreciated.

Thanks
Chris

 

[undercover]

A common problem on the Halsteads which a rgi could fix within minutes.

Boiler needs a service.

 

[howarthcd]

Thanks for the advice - I guess that a service would be a good idea.

You say that this is a common problem, but what is the likely cause? I'd like to know what the possible cause is so that I can be confident that an engineer's diagnosis is correct.

Thanks
Chris

 

[gez02]

I dont think he's gonna tell you in case you go messin in the combustion chamber.

However, i've just done a search and Halsteads suffer from fan problems and blocked heat exchangers.

 

[howarthcd]

This evening the plate heat exchanger was removed for inspection but no calcium deposits or blockages were found, however there was a ~1cm diameter ball of calcium that was ejected from the bypass pipe upon removal.

The plate heat exchanger was re-fitted, and upon testing the situation initially appeared to have improved, however after about 10 mins of use the modulation was experienced again on both DHW and CH.

One thing that I have noticed is that the burner cuts out when a gust of wind occurs outside (we live in an area that is quite windy) - could this behaviour be caused by low burner pressure?

Thanks
Chris

 

[spacethegas]

if you feel that there are no problems associated with the calorifier & that you have a wind problem (arf arf ) then you must contact a qualified person (not a doctor, arf arf ) as has been said before.

 

[howarthcd]

Hi All

Thanks for your replies.

Something that I've just noticed - comparing the flue outside with those of our neighbours' (we all have the same boilers) might well have just given me a clue - it looks like the air intake has been sealed off, which would explain why the boiler worked fine when the engineer opened the front cover of the boiler, therefore allowing air in. He diagnosed this as being a fault with the APS which was duly replaced.

Could anyone cofirm whether the flue and air intake is a combined unit on the Ace High?

Many thanks

Chris

 

[MANDATE]

The flue and air ducts are concentric to each other.
Have you not got the installation manual?

 

[howarthcd]

I do have the manual but it's not clear from that unfortunately.

Yes the flue does consist of two concentric pipes.

Thanks
Chris

 

[MANDATE]

Did you mean something different by 'combined'.
To me if there concentric they must be combined.
I know the diagrams show two different positions on one boiler, which I think could be clearer.

 

[howarthcd]

Thanks for all of the responses.

Just to elaborate in case others stumble across this post in the future, the problem was that the outside air intake had been inadvertedly (I assume) sealed off by a previous owner. Now that the intake has been unblocked the boiler is better than it has been since we moved into the house.

I suspect that air was previously being sucked in to the boiler past the inner cover's foam seal (the cover wasn't as tightly screwed down as it should have been), and that the foam seal expanded slightly when the boiler warmed up, restricting the air flow even more and either triggering the APS or extinguising the flame due to suffocation.

Cheers
Chris