Ideal Isar M30100 - Backfiring

[FordyX]

Hi all
recently the boiler is doing what can only be descibed as backfiring. It will blow the flame out, then relight 3 times before showing the error code L-F. Reset it and it will fire up again with no issues then run for a while before backfiring again.
It will fill a bath with hot water with no issues and heat the house for a while before the backfiring starts again.
In the last couple of weeks its had a new PCB, ignition electrode and gas valve, could it be the diverter valve now?
The condensate pipe is clear also.
Thanks in advance of any advice as to what the problem could be now
Cheers

 

[gas4you]

Has your engineer checked the working pressure at the gas meter?

 

[Agile]

Was the PCB and the gas valve both changed in an unsuccessful attempt to cure the fault?

If so then did you pay for them and to some wally who was unable to correctly diagnose the fault?

It sounds as if you would have been better off calling the Ideal service engineers. I assume they still do out of warranty calls? We dont seem to hear much about them here.

Tony

 

[FordyX]

Thanks for the responses....

Nope, engineer has not checked the gas pressure

PCB was changed due to that dying then it developed the same L-F error code so electrode was replaced, then it started L-Fing again so the valve was replaced and in between all that happening its developed this backfiring issue.

Will get my engineer back out to check pressure

Thanks again

 

[Agile]

One might question the capabilities of an engineer who attends a backfiring boiler but does not check the working pressure at the meter!

 

[weargas]

small white pipe goes from the combustion chamber to the gas valve. If you take it off and find water in it (just a couple of drops) then there's your problem. Caused by one of three things,
1, condensate pipe restricted or blocked. That boiler will produce 2 litres of condensation per hour in the right conditions so what might look like a clear condensate pipe can easily turn into a backed up condensate pipe.
2, auto air vent leaking. th ewater will run onto the bottom of the combustion chamber and make it's way into the white compensation tube mentioned earlier.
3, cracked sump or heat ex. bin the boiler.
My money's on a restricted condensate pipe. Mains water (not poured water) down it will usually clear it. Filling loop is ideal if it's close enough.

 

[Agile]

Those aluminium heat exchangers can produce quite a lot of white/clear jelly like hydroxides to block the condensate outlet.

Has anyone found any acid which successfully dissolves the deposits?

Tony

 

[ChrisR]

Phosphoric's a strong possibility. Try Kamco FX2.

 

[Agile]

The phosphate is not that soluble and has the disadvantage that it forms other associations with other chemicals which can be quite insoluble.

The hydroxide is easily dissolved by nitric acid which would seem to be the obvious solution.

However, buying nitric acid may not be very easy in smaller quantities.

Has anyone tried nitric acid and can anyone suggest where it can be obtained in smaller qualtities?

I understand that schools dont actually do any proper hands on chemistry any more "because its too dangerous"!

Tony