Gas working pressure drop

billy_smith · 4 Nov 2008

What is the permissable working pressure drop between the gas meter and the inlet supply at the boiler.Is 1mb correct ???

I just installed a Valliant Ecotec plus 831,Installed 28mm copper from meter outlet right up to the 15mm connection on the Valliant and working pressure drop is 3mb ???

No problem with working pressure,still getting in excess of 17mb at inlet but I did think a 3mb drop was alot !!

Deleted member 105431 · 4 Nov 2008

thats fine. between the appliance gas cock and the test point on the gas valve there is a loss of 2-3 mbar which is normal. Gas rate the boiler and check the CO2 with a fga and it'll run perfectly. Great boilers imho.

billy_smith · 4 Nov 2008

Hi,

I did commision the boiler today.Gas rate was perfect the only other query I did have was the C02 percentage,I had a reading of 14.3% yet the co/co2 ratio was 0.0006 which is fine !!!

corgiman · 4 Nov 2008

Dont think Vaillant give a monkeys about the CO/CO2 do they?

billy_smith · 4 Nov 2008

Yeah I was thinking along the same lines,The only thing I did see was towards the back of M/I and it said....

When RENEWING the gas valve adjust co2 levels to 9.1%

As I said the working pressure was good,gas rate good and the co/co2 percentage was 0.0006 so I passed the system today after installation !!!

sooey · 4 Nov 2008

With the ecotecs if the co2% is off the co goes off the scale.
If it was really reading 14.3 you need to get back there quick and adjust it, the ratio doesn't come into it with band a boilers.

ollski · 4 Nov 2008

corgiman said:
Dont think Vaillant give a monkeys about the CO/CO2 do they?

I was looking at that in the book that came with the replacement pcb, although it was virtually all pictures an dno instruction I think the general drift was that there is a min / max co2 to set.

Gasguru · 5 Nov 2008

billy_smith said:
I had a reading of 14.3% yet the co/co2 ratio was 0.0006 which is fine !!!

Did you calibrate your FGA in fresh air...did it show about 20.9% oxygen and zero CO ppm?

Sounds to me your FGA has a serious problem...you can't get 14.3% CO2..the mix wouldn't combust and the massive CO would kill the sensors.

Get back to the job double quick.

Agile · 5 Nov 2008

I would also question how you can say that you have commissioned the boiler if the CO² is way higher than the manufacturers operating parameters!

Its better that I dont say what I would like to!

This would have been better placed in the Combustion Chamber!

Tony

woogas · 5 Nov 2008

What is the permissable working pressure drop between the gas meter and the inlet supply at the boiler.Is 1mb correct ??? .

With a new pipe run that has been pipe sized (granted 28mm should be plenty sufficient) im on the understanding no more than 1mbar pressure loss to boiler with other appliances in operation

Deleted member 105431 · 5 Nov 2008

On any band a boiler including the Vaillants the CO2 is as important as the burner pressure on an older conventionally fired/aspirated burner (such as a glow worm ultimate for example). Either your fga is faulty or the gas valve needs adjustment.

billy_smith · 5 Nov 2008

Cheers guys,

Anyway,went back today with a different analyser,All reading are what M/I states,turns out there must be a fault with my FGA,I have a sprint V2 ,I did notice on the top of the screen this WOOD PELLET DRY !

Any thoughts why this would be ??

superdupergasman · 5 Nov 2008

you have pressed the function key during the start up faze and switched from the natural gas to a different setting.

when purging at about 20 ses press function and it should step through the different gasses, oils etc you can test.

billy_smith · 5 Nov 2008

Superb mate,I have just switched back to natural gas,No idea who changed that then !!!!

Will give FGA a try tomorrow and see what happens

superdupergasman · 5 Nov 2008

when was the last time it was calibrated?? Might be due...should be done once a year.

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Gas working pressure drop

Deleted member 105431

Deleted member 105431

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