Orion System Two Condenser Head Pressure Module - Manual (Page 15)

Technical Guide
Two Condenser Head Pressure Module
15
Troubleshooting
Head Pressure Module Valve/Fan
Position Troubleshooting
If confi gured for Water valve:
Aout Signal is 2 to 10 volts.
2 volts = 0% valve position or fully closed
10 volts = 100% valve position or fully open
PWM signal is not used for water valve but does modulate.
At Startup for cooling, valve will open to 75% or 8 volts for 3
minutes then will modulate every 30 seconds to try to maintain
head pressure setpoint.
For heating, valve will open and stay at 100%.
If confi gured for Air Condenser Fan:
Aout Signal is 0 to 10 volts.
Minimum fan speed is 1.5 volts. ( 15%)
Maximum fan speed is 10 volts. ( 100%)
Anything less than 1.5 volts the fan will be off.
PWM signal is 0 to 100%
PWM+ (to ground) will always read 24 vdc.
PWM- (to ground) can be measured for volts dc and this
formula will tell you the percentage signal: (24 – measured
value)/24 (measured value = PWM- to ground)
PWM-
0 volts = 100% fan speed
6 volts = 75% fan speed
12 volts = 50% fan speed
18 volts = 25% fan speed
20.4 volts = 15% fan speed
Above 20.4 volts = 0% fan speed
At Startup for cooling, fan will start at 50% then will
modulate every 30 seconds to try to maintain head pressure
setpoint.
For heating, fan will run and stay at 100%.
Safeties:
If head pressure signal is above 500 psig, fan will go to 100%
(high pressure safety).
If head pressure signal is below 1 psig, fan will go to 100%
(assuming bad sensor).
Revised 11/5/13