Alpha Technologies Radium MiniBay - Manual (Page 32)

2 044-001-C0-00, Rev. C
2.0 DC Air Conditioner, continued
2.10 DC Air Conditioner Trouble Shooting
1. Check that wire connections and input voltage are correct.
2. Check the evaporator and condenser thermostat wires are not reversed. These are on
the inside of the evaporator box and look like telephone jacks. The evaporator sensor is
attached to the suction line inside the evaporator box. The condenser sensor goes to the
outside and attaches to the discharge line. Look on the front of the PCBA for silkscreen
connector label “EVAP” and “COND”. If these are reversed the condenser fans will not
turn on, and the circuit breaker will trip.
. When the breaker is turned on, both evaporator fans should run continuously.
4. Verify the compressor comes on 10 seconds after pulling the setpoint jumper.
5. Watch the sight glass for bubbles. Bubbles should go to clear liquid after about a minute.
If there are no bubbles or liquid flow, or the moisture indicator shows wet and the bubbles
don't clear, there is low or no charge. This is not field serviceable, and the unit should be
replaced.
6. Check the discharge line to see if it is warming up. Both condenser fans should come on
(first one, then the other) when discharge line is above 104ºF (40ºC).
7. If unit control board indicates a yellow LED minor alarm, check for plugged outdoor
condenser or bad condenser fan.
8. If the unit control board indicates a red LED major alarm, the compressor may be over
heated or overloaded, or there is a bad three-phase connection to the compressor. Check
for a plugged outdoor condenser, or compressor overload.
9. Using a DC clamp-on ampere probe, check the input current to the air conditioner while
the compressor is running. The 48VDC air conditioner should draw between 6A and
10.4A (10.4 FLA, Full Load Amps), for normal operation. The 24VDC air conditioner
should draw between 12A and 20.8A (20.8 FLA).
10. Check the Delta-T across the evaporator coil. It should be between 9ºF and 18ºF (5ºC
and 10ºC).
11. The unit is overloaded if the FLA is too high and evaporator Delta-T is 9ºF (5ºC).
• Check heat dissipation load inside the cabinet.
• Check blocked condenser or bad condenser fans.
12 Check the suction line entering the compressor. It should be getting cooler. If it is not
getting colder, and the sight glass looks full or clear, there may be a refrigerant blockage
at the TX valve screen (this is not field serviceable). Replace the unit and send it back
for evaluation and repair. To protect the unit from damage during shipping, use proper
packing to keep the unit in an upright vertical position.
ATTENTION:
Contact Alpha Technical Service to determine proper diagnosis. See page for contact information.