Purging a hydronic heat system

[jmmybear730]

I recently moved my oil burner and boiler to a new location in my house. After replumbing, wiring and venting, i was able to finally start the system up. The system fired right up after I bled the oil line. My next problem was that the burner was making hot water for use, i.e. kitchen & bath, but the pipe for the baseboard heat is hot but i feel the water just isn't circulating. The circulating pump is running but none of the baseboards get warm. I have two bleeder valves inline and they have been bled. What is the next step?

[buffalobill]

"If your boiler makes your domestic hot water through a device called a tank less coil then if the controller is working correctly it will prevent the circulator pump from operating until the temperature setting gets up to the minimum for domestic hot water. On a call for heat the system will rise to the (high) limit setting which should be at least 20 degrees higher than the low setting. The differential setting is for the low setting only." from and many more words you need of advice see source:

[Paul Franklin]

If you know the the circ is running but the radiators aren't hot, it's most likely air-locked. Just bleeding at the radiators won't necessarily remove an air-lock because water can enter the bleed valve from either the feed side of the radiator or the return, so you can get water out of the bleed but still have an air-lock.

When you redid the piping did you create any isolated high spots where the pipe goes up, over, and down without an air vent? Those areas almost always air-lock when drained.

In any case, you're going to need to pressure purge it Hard to describe exactly how to do it without knowing your piping layout, zones, drains and shutoffs. But the idea is to use full water pressure (supplied via a fast-fill valve or garden hose) to force water through each zone and loop of piping, 1 at a time. This forces any trapped air out. With a little head scratching you can figure out which valves to close and which drains to open to achieve this. Of course the boiler should be off when you do this.

HTH,

Paul