The A29/A30 alarm only applies to DC powered supply fans. If this alarm is displayed when AC fans are installed, change the SF1 setting in the D menu from 0 to 1 or from AUT/DC to AC. If using the PGD, change option Ch1 in the Manufacturer Menu to AC. See Chapter 1: Model Identification to determine supply fan power input.
When the DC fan is running, pressure is built up across the air pressure differential switches (PF2 & PF3) and the circuit between terminals 5 & 9 will close. If the pressure switch does not close after 60 seconds, A29/30 will trigger, indicating problems with the supply fan.
|Possible Cause||Component to Check||Recommended Action|
|No power to DC fan||Verify 48VDC presence on DC breaker. Verify 48VDC across 12 and 131 to the supply fan||Correct DC power supply.|
|Incorrect DC polarity||Placing the red probe on the +48 terminal and the black probe on the -48 terminal should give a +48VDC reading. Verify controller side as well.||Correct DC polarity.|
|No speed signal to DC fan||Speed signal between 11 and 12.||Verify 0-10 VDC signal between terminal 11 and 12.|
|Incorrect alarm wiring||Alarm wiring||Verify wiring. See DC Fan Air Flow Alarm Wiring.|
|Faulty air pressure differential switch||Air pressure differential switch should close when the fan is running at high speed||Replace air pressure differential switch.|