Old coal converted to oil boiler not heating bled radiators

Old 11-25-16, 06:48 AM
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Old coal converted to oil boiler not heating bled radiators

I drained my old boiler a few years ago to mothball a house that was vacant. The boiler is coal, converted to oil with two low returns. I recently refilled the boiler, bled all of the radiators multiple times and still no heat to the radiators. Against my better suspicions, I just replaced both circulator pumps. No luck.

The boiler has two pipes flowing out of the top of the boiler. The two pipes each have large thrush flow valves. The pipes curve 90 degrees at the top and have self-bleeding float valves (I think that's what they are). The pipes below the valves are hot and and above are cold when the boiler is at temperature. The boiler has 12-15 lbs of pressure. I have tried moving the switch on the valves from "open" to "normal" and vice-versa, with no change. Coming off of the horizontal of the valves is the bladder pressure tank. When I turn the power to the circulators on and off, I can hear water and sloshing back and forth in the pressure tank. I am suspecting an air pocket in this area is preventing water from circulating. If so, how do I correct it?

Whoever solves this for me will be my new best friend.
Old 11-26-16, 05:24 PM
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Do the return pipes have purge valves (garden hose connection)? How have you been bleeding the radiators, with the circulator(s) on or off? If when on, try letting the system off for a few (5-10) minutes & bleed again with the circulator(s) off. If bleeding when off try with circulator(s) on.
Old 12-01-16, 03:16 PM
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Try temporarily jacking up the pressure to 25-28 psi, and bleed some more.

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