I have an oil boiler and wood gassification boiler. They are hooked in parallel to each other. The oil boiler has a circulation pump just above it's output that turns on and feeds into the primary loop only when the buffer tank for the wood burning system gets below whatever temperature I set the aquastat on the tank at. Right now I am only heating hot water with the gassification boiler so I have the buffer tank above 140 degrees pretty much all the time by burning one fire a day. For some reason, the circulation pump above the oil boiler is not working. The circulation pump is less than a year old. Installed when the Gasser went in last September, and came on line October 1st. I determined this when we let the Gasser go out and the oil boiler was running and trying to heat up the indirect tank but could not do it. I felt the pipe above the boiler and below the circ pump. It was plenty hot. But a foot or so above the circ pump, not hot at all. ? What do you think could cause this?