Electrical Questions - Hussmann Proto-Aire Installation Manual

Electrical Questions

Problem A: The compressor will not turn ON or will not run.
Step A1 Visually observe if the Alarm on the control board is ON. If it ON, go to
step A2. If it is OFF, go to Step A9.
Step A2 Access the protocol and enter the Force Comp On submenu. Enter the
compressor number you wish to turn ON. Visually observe if the correct
compressor relay output LED on the control board, turn ON. If turn ON, got
to Step A3. If it does not turn ON, go to step A7.
Step A3 If the compressor contactor is energized, verify that the compressor turned
ON by cycling the compressor circuit breaker (the compressor should turn
ON and OFF with the circuit breaker) or use an amp probe and measure all
three phase wires between the contactor and the compressor. If the
compressor contactor did not energize, go to Step A6.
Step A4 If the compressor contactor energized, but the compressor cannot be cycled
with the circuit breaker, you will need to open up the compressor terminal
box located on the side of the compressor, and ensure that the power wires
are tightened down. Important: you should turn the compressor circuit
breaker off before implementing this check.
Step A5 If the compressor wires are tight with the terminal box, the compressor may
be damaged internally and may need to be replaced.
Step A6 Problem appears to be located in the control circuit wiring, most likely in
one of the safeties. Referring to the supplied customized wiring diagram,
use a digital voltmeter and determine where the circuit is being broken. The
control circuit originates from the phase monitor, passes through the control
board safety switch, the discharge line thermostat, and finally through the
electronic oil level control safety.
Step A7 If you cannot force the compressor ON through the controller parameters:
1. No electric defrost is currently engaged. Electric defrosts implement a
compressor shedding routine, which may be keeping the particular
compressor you want to energize off-line.
2. The correct number of compressors is installed.
3. Check that the suction pressure is not below 2 psi activate the vacuum
prevention routine which will not allow the compressors to turn ON.
Step A8 If the preceding parameters check out, you may need to replace the
electronic control board.
Protocol™ Installation and
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Service Manual