How to set Pressuretrol

Steve Garson_2

Question on pressuretrol settings:  New Burnham Independence steam boiler in my son's apartment has pressuretrol with subtractive differential.  If the cut-out pressure is set to 1 psi.  What should the differential setting be?  My instinct tells me 0.5psi, but the scales does not seem to have a scale close to this level.  Honeywell L404F1367



Steve Garson

Boston

Jamie Hall

Have to admit

that I haven't looked at that particular pressuretrol -- but it is quite possible that it doesn't go that low.  What is the smallest differential you can set?  If you can set the main to almost anything below 2, and then a small differential, that should get you started.  If you are running vapour, you should be using a vaporstat anyway... just because of this problem.  The real trick with a pressuretrol is to to set it basically as low as you can, and then just make sure that as the pressure drops with the thermostat still calling that the burner will come back on.  If it doesn't, you will need to dial up the cutout until it does...