circulating pump install for wood fired outside boiler
I built my own wood fired boiler and have run it for 2 winters but am still having trouble with air getting to the circulating pump and the pump cavitating. Any suggestions? I wasn't sure where best to put the pump when I built it so it is on the supply line but inside the house about 30 feet from the boiler.
I'm up to my neck scoping a couple boiler jobs for an apartment complex this morning, so you caught me at a good time.
Picture your water loop, and the line returning from your house. Here's the order of devices, starting at the exterior house wall:
Line returns from house
At the point near where the line enters the boiler, install a drain valve
Line exits boiler, install a tee with a pressure relief valve and a tee with a drain valve
Install an air separator 2-3ft away from the boiler outlet
Install a tank tee in the line after the separator, with a branch going to an expansion tank (you have to follow the expansion tank manufacturer's and separator manufacturer's recommendations regarding elevations)
Between the tank tee and the tank, pipe in the make up water line (with fill valve and backflow preventer - again follow the manuf's recommendations)
After the tank tee, install your circulator pump, then a check valve, then a tee with a drain valve
If you have temperature control, the element will get clamped or piped in after the pump
It's good practice to also have a low water cut off, but I don't know what kind of control you have on your boiler
If you go onto web sites like Taco's (pumps) or Amtrol's (expansion tanks) or Spirotherm's (air separators), they'll have files you can download that show more detail on the order for various types of systems and components.
Thank you very much Aggie67.... I will be sure to change things to match your suggestions. As it is now I have the circulator on the supply side or the loop and it goes through the house and workshop before returning to the boiler. Again much appreciated.