Pub. No. OM-A-75 REV. 4 — March 2006
17
M. Top condenser coils cool when unit
in operation.
1. Refrigerant shortage.
2. Compressor inefficient.
1. Repair leak and recharge.
2. Repair or replace.
N. Unit runs but air temperature is
high.
NOTE:
Outlet air temperature gauge
may read higher than actual
temperatures at low air flow conditions.
1. Refrigerant leak.
2. Evaporator controls set too high.
3. Filter/dryer clogged.
4. Refrigerant shortage.
5. Dirty condenser.
6. Air in system.
7. Compressor inefficient.
8. Evaporator control(s) stuck.
9. Defective insulation.
10. Air overload.
11. Unit too small.
12. High ambient.
13. Entering air temperature too high.
1. Locate with leak detector. Repair
or replace defective part.
2. Refer to L – above.
3. Replace.
4. Repair leak and recharge.
5. Clean condenser.
6. Check reason, repair, vacuum,
recharge.
7. Repair or replace.
8. Repair as required, adjust.
9. Repair.
10. Reduce load.
11. Add unit or replace.
12. Reduce or change location.
13. Lower entering air temperature.
P. Unit runs but low air pressure.
1. System pressure low.
2. Precooler and/or evaporator
clogged.
3. Incorrect piping.
4. Air overload.
5. Unit too small.
6. Excess water in unit.
7. Evaporator freeze-up.
8. Clogged air compressor intake
filter.
9. Dirty air system.
1. Increase pressure.
2. Back-flush using mild detergent,
Figure 2 on Page 10.
3. Increase line size and/or correct
piping as required.
4. Reduce overload.
5. Add another unit or replace with
larger unit.
6. Check drain, repair or replace if
needed.
7. Adjust hot gas bypass valve.
8. Clean or replace air intake filter.
9. Back-flush as described in
Figure 2 on Page 10.
Q. Unit runs, but air flow erratic or
zero.
1. Freeze-up.
2. Precooler and/or evaporator
clogged.
3. Restriction in piping upstream
from unit.
1. Check suction temperature at
evaporator outlet or turn off unit
and allow it to thaw to determine
if this is problem. Adjust controls
at no-load if freezing is occurring.
2. Refer to P-2 above.
3. Correct as required.
R. Evaporator freeze-up.
1. Hot gas bypass valve out of
adjustment.
1. Adjust suction pressure. Adjust hot
gas bypass valve.
S. Condenser fan blows outward.
1. Improper wiring at disconnect
(3-phase only)
1. Reverse two wires.
Table 1 — Troubleshooting Guide, continued
Symptoms
Cause
Remedy