Mend > Plumbing

working pressure drop?

went to repair falcon ll boiler nothing wrong with sensors dc voltage across both wires were correct but gas valve wouldn't modulate inlet test point connected to manometer read 25mbar high i know same at meter and don't worry gas server notified faulty governor but when measured working pressure 6mbar ????? any ideas phoned corgi tech could'nt help never seen drop like that so don't know gas pipe blockage maybe

mik
November 2008

Falcon Falcon LL D.I.Y, Plumbing Working Pressure Drop

seen a few with a filter at gas inlet to appliance, could be blocked like you say, pipework is nearly always undersized but same as you said you'd expect still around 17mbar if it was just a sizing issue. best of luck

iain
November 2008

If it is an old installation it may have a top hat type filter in the pipe work if so it might be full of debris .

chris(retired gas engineer 30 years)
November 2008

working pressure at meter 20mbar 22mm right through building definitely undersized for amount of run but would still not expect that much drop this is what's having me wonder never seen a drop this much like yourself i've seen working pressure at 10 and 12, same reasons 15mm

mik
November 2008

IMO Standing pressure is a waste of time unless seriously high,

Id check appliance working pressure at meter (21 mbar ideally) and you said you had 6 mbar working pressure at appliance, obviously ideally around 20.

After that it would be pipe sizing/blockage

iain
November 2008

25mbar standing pressure???? True standing pressure measured after running appliance with meter on p1.

Ive had working pressure on a baxi of around 10mbar which was just wrong pipe sizing, 15mm from meter to appliance lots of bends etc.

What was working pressure at meter?

iain
November 2008