Pressure Loss Compensation - Honeywell HVAC400x Applications Manual

HVAC400X – APPLICATION MANUAL
10.13.6

Pressure Loss Compensation

When you pressurize a long pipe that has many outlets, the best position for the sensor is in the middle of the pipe
(the position 2 in the figure). You can also put the sensor directly after the pump. This gives the right pressure
directly after the pump, but farther in the pipe, the pressure drops with the flow.
A
A. Pressure.
B. No flow.
C. With flow.
P3.13.6.1 ENABLE SETPOINT 1 (ID1189)
You can use this parameter to enable the pressure loss compensation in the pump system.
P3.13.6.2 SETPOINT 1 MAX COMPENSATION (ID 1190)
You can use this parameter to set the maximum compensation for PID setpoint value that is applied when the
output frequency of the drive is at the maximum frequency.
The sensor is put in position 1. The pressure in the pipe stays constant when there is no flow.
But with flow, the pressure decreases farther in the pipe. To compensate for this, lift the setpoint as the flow
increases. Then the output frequency makes an estimate of the flow, and the setpoint increases linearly with the
flow.
EN2B-0417GE51 R0719
PT
E
Fig. 42. The position of the pressure sensor
Legend
B
C
PT
F
D. Pipe length.
E. Position 1.
F. Position 2.
146
D