heatingplumbing
I currently have a forced hot water heating system with 3 zones, all of which have the circulator pump on the supply side of the line. I need to install a 4th zone and am being told that putting the circulator on the return side is more efficient.
What are the pros and cons of the circulator's location? Are there issues having some on one side and some on the other?
The hand valves and spigots near the furnace are for isolating and draining the zones to servicing the radiators. To bleed the system, you would find a bleed valve at a high point, often at each radiator. You may have to remove a cover to find it, and it may require a screwdriver or small wrench to operate the valve. Make sure to have some rags handy to cleanup any water that comes out. When you're finished, check the pressure in the system and add more water from the water main input if necessary.
Here's a diagram of a hot water recirculating system
As I understand it, the idea here is that the recirculating system runs hot water around the pipework to keep the temperature hot near the faucets/taps. This allows for instant hot water at faucets/taps far from the water heater.
Even when no taps are running the pump should be actively maintaining the circulation as needed. It needs to do this as any unlagged pipes will cool the water in them if no faucets/taps are drawing hot water.
When the water near the faucets/taps is sufficiently hot, the "Aquastat" will turn the pump off.
Your power feed to the recirculating system should be via a timer, or other device, that lets the pump run whenever the "Aquastat" feels necessary. This should be "on" during any times of the day when you are likely to use the faucets/taps.
Some ideas:
You should be able to test this with a thermometer and a voltmeter if you can locate the "aquastat"
Best Answer
Water pumps pump water, not air, so putting it on supply side makes water allways available for circulator to pump. If you put that circulator on other side it could be hard to fill system with water and avoid air pockets. And basicly you can't pump air with water pump as it makes them break.