Wood burning boiler

Jim_5

Having some trouble with a outside wood burning boiler. It was out of water, having sprung a leak in the pex tubing. I repaired the leak and filled the unit with water. The pump on these are setup to pump away from furnace. The pump does run but doesn't circulate. I disconnected the line at the pump and let the water run by gravity thru the entire system backwards, the return is higher on the boiler than the supply. It has a zone valve which directs the water into the furnace coil when calling for heat. I did open and close this zone while the water ran. The pump runs 24 hours a day. The zone valve is looped up then down at the frunace. A perfect place to trap air. I thought pumping away it couldn't air lock. I've considered drilling and tapping the top of the loop for bleeder's. Also disconnecting the return and letting the water run for awhile with the pump on. I need this thing running before cold weather. Any suggestions.

hr

How do you know

the pump is running? I have seen them break the shaft and the motor spins, and draws current, indicated by an amprobe, but the impeller is not spinning!
Remove the motor from the volute, carefully as the sometimes built steam if they have cavitated for awhile, and hit the power for a second. It will either spin or it won't

If it spins you may have an air lock.

I install low water cutoff switches on all the woodburners I sell. Prevents costly mistakes, like pump meltdowns, and air locked systems. Use the alarm circuit, and a bell or light, to let you know of a low water situation.

hot rod

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Jim_5

I did remove the pump it spins it runs. What makes you look bad is it circulated before. I'm sure the homeowner will question my adding 2 bleeder's inside, but I think that's my next step.