Quote:
Originally Posted by MEMPHIS91
Bi-directional flow txvs. Why do I need check valves if these can flow backwards?
I saw a unit today that did heating and cooling. Not a single check valve in the system. Not even a bypass loop or anything.
Are most txvs bi-directional?
|
Some tx valves have a built-in check valve. When they see reverse pressure, the check valve opens and lets the liquid through without dropping much pressure at all. You still need one for each heat exchanger, though. Electronic expansion valves are naturally bidirectional and don't need a check valve. The unit will have thermometer sensors on each hx to let the controller know what they are doing.