Figure this one out

[Nostrum]

Worcester 24i RSF (CDI style)


Tenant reported the hot water was overly hot. Arrived, tested burner pressures, 11.5mb max, 3.4mb min, should be 13.6 and 1 respectively but seeing as the water is too hot, didn't touch and potentially make worse. Check hot water sensor/thermistor. Phoned technical whilst there to confirm resistance of thermistor, tech guy says its out of range, ideal. Ordered a new temp sensor.

Re-visit, fit sensor, check water, still the same. Phone tech, ask for the voltage for the modureg unit on gas valve. Tech guy, obviously reading off the chart says voltages are wrong and his fault chart says PCB. OK, wasn't overly convinced but authorised to change so ordered up.

Re-visit, fit PCB, fire up... the same. Annoyed now, re-test burner pressures, same as before. Decide to adjust B.P, max up to 13.6mb fine, minimum oops to low, down to 0mb.... hang on, boiler is still lit?

Scratch head.

scratch head.

Get other guage from van, 0mb. Boiler is still firing well, not just a tickle on the burner.

Notice a pilot adjustment on gas valve, pretty sure the RSF range were all auto ignition, phone technical, this gas valve was never fitted to this boiler.

Anyway to cut a long story short, the boiler was ID'd and a new boiler is going in, but can anyone explain how the gas is bypassing the test nipple? I'm stumped, can only presume its an internal fault to the gas valve, but has anyone come across it before?

 

[zeebeedee]

So your saying someone had fitted an incorrect gas valve?

 

[Nostrum]

Seems that way yeah. Whether or not it is anything to do with the main problem, i'm not convinced. Reckon the gas valve is just duff.

 

[zeebeedee]

Riddor that!

 

[Nostrum]

Yep, and to add insult to injury, the tenant's son or grandson is a gassafe inspector in Liverpool!

it was only when i adjusted the B.P i noticed the pilot adjustment, can't see how this could pass through onto the burner though? unless it's been modified or something similar.

 

[vern]

Yep, and to add insult to injury, the tenant's son or grandson is a gassafe inspector in Liverpool!

it was only when i adjusted the B.P i noticed the pilot adjustment, can't see how this could pass through onto the burner though? unless it's been modified or something similar.

What gas valve make was fitted should be a Dungs?
also B.P high is 14.8 MBar low 1.5 Mbar 24 cdi?

 

[Nostrum]

It was a SIT tandem, 837 I think. B.P on data badge Max 13.6 min according to Worcester 1mb?

 

[vern]

It was a SIT tandem, 837 I think. B.P on data badge Max 13.6 min according to Worcester 1mb?

Pmsl only dungs on these, right hand side above PRV that's off a Gloworm or similar with auto ignition with pilot, not direct burner ignition as the dungs, how did the electrics fit the solenoids they are totally different?

 

[Nostrum]

Perfect fit, whether or not they've modified the valve, or maybe it was a manufacturing fault, I've no idea. Wiring had the Worcester plug on to go onto the board as well.

I'm not overly familiar with these so it wasn't obvious ( a gas valve is a gas valve when your not comparing them) until I saw the pilot adjustment!

Any ideas how it was working even when I wound the minimum pressure down to zero and disconnected the modureg!!?.? Surely the pilot bypass wouldn't go on to the main burner? This is what's baffling me rather than the fact some numptes fitted the wrong valve (especially after seeing their work in the other houses we've just taken on through this housing association contract)

 

[AlexGas]

That is very odd!
Have you noticed any cameras in the room?
:camera: