Gas valve?

[macka09]

Another question lads sorry. When my colleagues alter the gas/air ratio on a combi they only use a analyser but looking through some makers instructions it's states that a manometer should also be used. I know MIs have to be followed but in this picture

What is the p in and P out? Are these the ports that the manometer would be attached to?? Really sorry for all the sh ite questions.

 

[dancinplumba]

P in is inlet pressure, p out is out let pressure

 

[macka09]

So p in is operating pressure and p out is burner pressure???

 

[dancinplumba]

Yes, but on this valve p out is about zero and we don't measure it, we do fga

 

[macka09]

Ok and that's to check that the ratios correspond with the makers instructions.

 

[dancinplumba]

Yes, to see if its burning correctly, adjustment on this valve is done at the offset screw

 

[Leo21]

P is negative pressure(zero governer), so you can't use a u gauge. That's why we use the fga. The inlet gas port we use to see if there's enough gas there.

 

[dancinplumba]

Some manu's like wircestershyite/ boosh want you to also check fan pressure, pressure drop thru heat ex. And you use your manometer measure this

 

[Leo21]

Some manu's like wircestershyite/ boosh want you to also check fan pressure, pressure drop thru heat ex. And you use your manometer measure this

Wircestershyite! Love it.