Vaporstat

terry_6

I've been told by a local contractor that my system just won't run below 1 psi and he wants to up the pressure. I've rebuilt the piping (near and far) according to Dan's book and recently installed a Vaporstat, hoping to run it, as Dan says, between 10 and 4 oz. but the water line jumps too much (making the pressure jump also) so the system short cycles (45 seconds or so..) which is putting a huge strain on the auto ignite which then shuts down. The wife isn't keen on the cold. I've upped the setting to run between 16 and 4 oz. and it allows it to run a bit longer but not much. I've gone through Dan's book again, checked the hot points on this website and don't find a smoking gun. Any ideas before I call the local guy out again? The boiler is a little big for the system but not much; maybe downfire it a bit? Also when the steam leaves the system it sucks the water line up to the very top of the sight glass.

Unknown

Some things to check out

The description you gave is exactly what dirty, oily water does when you boil it. The short cycles might also indicate undersized vents, which will let air pressure build up before the air is all out, and the vaporstat sees pressure and shuts off the fire. Are your vents already hot when the vaporstat cycles?

Over firing causes water to leave out the returns, showing a low waterline, causing the Low Water Cut Off to cycle the fire off, and then the water immediatly returns to the boiler to repeat the action. I don't think this is what you described, though.

Noel