Chillew water pump
Chillew water pump
2
MisterDonut (Mechanical)
Secondary pump speeds should modulate in response to the remote secondary loop differential pressure signal. The set point will need to be refined after testing and balancing, but 10 psi is a typical starting point. The differential pressure signal is typically measuring the pressure difference between the chilled water supply and the chilled water return at the point in the secondary loop that has the greatest pressure loss between it and the secondary pumps.





RE: Chillew water pump
RE: Chillew water pump
Also the diff. press transmitter will give signal to VFD to modulate the pump water flow? or pump will modulate base on temperature difference?
RE: Chillew water pump
Thanks in advance.
RE: Chillew water pump
To begin with, look at the unit closest to the sensor. Estimate the pressure differential through this unit's coil, control valve and piping to and from the header. Assume the control valve is 80% open at maximum design flow. This amount is the pressure differential needed at that unit. Use that value as a starting point. If possible, test, adjust and balance the entire system and refine the set point as needed.
RE: Chillew water pump
When you say estimate the pressure differential through the units coil, control valve and piping to and from the header - does it mean the Total Pump Head?
If I have 30m Aq (~100 ft of water) total pump head does it mean that is my diff. pressure sensor setting?
Thank you in advance.
RE: Chillew water pump
The head required at the pump must overcome the losses in the supply and return piping as well as the losses through the control valves and coils. Some units are near the pump, so the piping losses between the pump and these units is lower. Some units are far from the pump, so there is more piping, and thus more piping losses, between the pump and these units. Each unit needs a certain amount of pressure differential between the supply and return piping so that water will flow through the control valve and coil. The set point to be maintained at the remote sensor must be enough to overcome the losses through the most remote unit.