Problems with Refilling Oil Fired Hot Water Boiler

[velvetfoot]

Not wood-fired, but I figure you guys might know.

A friend of mine drained his boiler because of the power outage.
He refilled it yesterday, but can't get it to heat.
Burner fired up and shut off at water temp of 180F.
Very little warmth coming from outlet.
It has an Extrol expansion tank with air scoop and that air valve on top.
It appears to filled, apparently too much since we fooled around with it without reading and it's at 20 psi now.
I understand that for his 2 story house it should be at 12 psi to match the expansion tank and fill valve (we put it on fast fill).
He swears there're no bleed valves.
I figure it's big air bubbles, but how to purge?
A friend at work suggested isolating each zone (there are 4 including the water heater), and cracking open the drain valve at the circulater to purge the air.

Any other ideas?

He'll probably just wound up hiring a plumber to come out, but they may be scarce with the power failure.

Thanks.

 

[peakbagger]

He needs to purge all the zones individually. Generally, the zone pump is on the return side of the loop (although I have seen them on the hot side). Assuming the pump is on the return and if there is an isolation valve between the pump and boiler, close that valve and open the drain valve on the pump. The automatic boiler makeup valve should start feeding water through the system and out the drain, run the water for a few minutes until there are no bubbles, than turn off the drain valve. Repeat for all zones one at a time. Note that the automatic makeup valves have screens on the inlet and can clog up when called for to supply large amounts of water, like you are doing. There is also an option to fast fill the system by flipping the level on the makeup valve up, I would avoid this as if its an old makeup valve, this sometimes takes out the diaphram on the make up valve rendering it useless. If there isnt an isolation valve between the pumps and the boiler, its probably time for the plumber.

Alternatively if he has baseboard, take a flashlight and make sure that there isnt a key coin valve on the top of the elbows hidden away on either side of the steel casing. If they are there he will need to remove the end caps to access the vents and be prepared to get wet when bleeding.

 

[velvetfoot]

Thanks for the tips.
I'll give him a call and see what the story is.