Cant adjust burner pressure on gas valve

[beesley121]

Hi guys,

just wanted to query something

If the a gas valve wont allow you to re-adjust burner pressure and

a) its within spec, +5 or -10% is this ok to leave and just make a note of it?
b) not in spec - is this AR

 

[Dsgas]

I would at risk this as it could vary before the next annual check. But I would like to find out the reason why.What type of gas valve/boiler.Has it got a partially blocked inlet filter?

 

[diamondgas]

What appliance/gas valve you playing with beesley121? A bit more info on what you're experiencing could help give more accurate a reply!

 

[beesley121]

I've had it twice now in 3 days thats why I'm asking to make sure I'm doing the right thing

Boiler was glowworm ultimate 80 and baxi bermuda 552

the glow worm flame picture was fine, ratio fine so left it as it is as it was within spec but I'm a bit worried now as it could possible go out of spec but when would the owners decide to have a service done again? That's my issue

as for the baxi, I AR that as flames were yellow, about 10 inches high and had sooted up the righthand side of the heat exchanger

 

[diamondgas]

Did you check the inlet pressure beesley121? Just wondering if it were the same as the outlet so wouldn't go any higher?

 

[beesley121]

Inlet was around 20mbar so the gas valve was definately 'working'to a point as the maximum burner pressure should have been 16.3 I think. It was within 5% of this but at the upper end, so I tried to readjust it back to 16.3.

I wouldnt have thought you could lose almost 4 mbar through one of these gas valves on restriction alone

 

[diamondgas]

Hi mate... Just checking mi's for the two boilers see if they're the same gas valves and they appear to be different ... SIT on the glowworm and Honywell on the baxi, is that correct?

Back to your original question though, personally I'd be happy to leave it and just make a note on any paperwork to the effect that it wasn't adjustable. If the appliance is otherwise working safely what is it 'At Risk' of and should therefore be left turned off? If you're seriously concerned then advise that the valve is replaced IMHO

I wouldn't worry regards their appliance being serviced again ... It was as it was when you were there. Anything can happen once you've left yeh? The Baxi, by the way, I'd have most likely ID'd because of the nature of the products of combustion it was producing! ............ Hohum

 

[Ermintrude]

Soot and high flames? It's not working properly is it so u can't just leave it. I would say evidence of incomplete combustion so ID and inoperable controls. Was ventilation there for both units?

 

[beesley121]

Suppose you right about it being ID!! Damn, good job I'm replacing the gas valve monday.

 

[Dsgas]

Agree ID Baxi. Capped off an ultimate 120ff on Monday. No adjustment and the valve wasn't seating and leavin a bloody permanent pilot.

 

[diamondgas]

Suppose you right about it being ID!! Damn, good job I'm replacing the gas valve monday.

If the BP was within MI's recomendations though then I'd be suspecting other issues causing the incorrect flame picture ... what else did you check?

 

[beesley121]

Sorry mate, think I've confused things

glowworm ultimate, Bp in spec, unable to adjust gas valve to bring it down from limit. flame pic and ratio fine

baxi bermuda 552, Bp out of spec, 18mb, unable to adjust Bp, flames yellow, 10 inches high, sooting of heat exchanger. AR'ed this but advice from here should have been it was ID

 

[Mike Jackson]

Agree ID Baxi. Capped off an ultimate 120ff on Monday. No adjustment and the valve wasn't seating and leavin a bloody permanent pilot.

This was a common problem on the early ultimates. The gas valves were awful, there was no governor built in, just a Venturi with a restrictor screw. I couldn't work out why the burner pressures were different each year when I went to service them until I took a failed gas valve out and took it apart.

 

[Dsgas]

AR glowworm and advise on a new gas valve as this could be a danger down the line. ID baxi sounds like new gas valve if non adjustable and overfiring.