Can buildin hydronic hot water pump vfd be controlled by a flow meter?
Can buildin hydronic hot water pump vfd be controlled by a flow meter?
(OP)
For energy savings, a vfd is replacing the constant speed motor controller for the building hot water pump. Usually, dp switches are installed at the pump output and 2/3rds out into the system. In this case, the line is in a pipe chase that will not allow DP installation on the piping anywhere near the end of the line. The piping is cast iron.
Q1: Can a strap-on flow meter be used at the 2/3rds location? It can be installed since no cutting or welding would be required, but not sure if flow measurement will provide an accurate way to control the pump speed.
Q2: Can DP switches be installed at the pump suction and discharge in lieu of 2/3rds? Will the nearby locations provide enough input on what the system needs really are?
Q1: Can a strap-on flow meter be used at the 2/3rds location? It can be installed since no cutting or welding would be required, but not sure if flow measurement will provide an accurate way to control the pump speed.
Q2: Can DP switches be installed at the pump suction and discharge in lieu of 2/3rds? Will the nearby locations provide enough input on what the system needs really are?





RE: Can buildin hydronic hot water pump vfd be controlled by a flow meter?
Taking a step back though are the control valves 2 way or 3 way valves as it sounds as if the exising system is a constant flow system.
RE: Can buildin hydronic hot water pump vfd be controlled by a flow meter?
RE: Can buildin hydronic hot water pump vfd be controlled by a flow meter?
I'd recommend considering valve percentage open to run the pump.
RE: Can buildin hydronic hot water pump vfd be controlled by a flow meter?
RE: Can buildin hydronic hot water pump vfd be controlled by a flow meter?
Thus the pressure or valve position inputs already mentioned.
RE: Can buildin hydronic hot water pump vfd be controlled by a flow meter?
Thanks to all, by the way. Very helpful input.