Reznor MASA Unit Installation Manual - Manual (Page 34)

Form I-COND, P/N 220746R6, Page 34
CAUTION
After cleanup is complete, remove the suction line filter drier.
See Hazard Levels, page 3.
d) Verify subcooling and superheat (refer to Start-Up Paragraph 9.2).
e) When the system is operating properly, remove the gauges.
IF the oil measured in Step 2 was not significantly less than that shown
in TABLE 10 or the acid test in Step 2 did not indicate a compressor
burnout, continue to the review in Step 13.
□
Step 13 . Review ALL Steps to ensure that nothing was
overlooked.
10.5 Compressor
Maintenance
and
Replacement
(cont’d)
10.0 Maintenance
and Service
(cont’d)
IMPORTANT: Do not release refrigerant to the atmosphere! If
required service procedures include the adding or removing
of refrigerant, the service technician must comply with all
national, state or province, and local laws.
The procedures discussed in this manual should only
be performed by a HVAC technician qualified in R-410A
refrigerant.
10.6 Troubleshooting
Chart
SYMPTOM POSSIBLE CAUSE REMEDY
A. Compressor will
not start.
1. Power off, loose electrical connections, or fuse
open.
1. Check disconnect switch, fuses, and wiring. Replace parts or repair as
necessary.
2. Compressor contactor not closing. 2. Check voltage to contactor coil, transformer, slave relay, and system.
Replace parts as necessary.
3. Internal compressor thermal overload open. 3. If compressor is hot, allow 2 hours to cool. See D. below.
4. Compressor defective. 4. Check compressor for electrical failure. Compressor may be seized;
check refrigerant. If necessary, replace compressor.
5. High or low pressure switch open or defective. 5. If manual reset (high pressure), reset switch. (Switch opens at 600±15
psi and will not reset above 400±15 psi.) If auto reset (low pressure) does
not reset and everything else is OK, replace switch.
B. Compressor
starts but cuts out
on low pressure
(low pressure
switch activates at
45 psig.)
1. Low refrigerant charge. 1. Check subcooling and superheat. (See Paragraph 9.2)
2. Airflow restricted. 2. Check for dirty evaporator coil, dirty filters, closed dampers, iced
evaporator coil, or improper belt. Check motor amps. Check duct design.
3. Restriction in refrigerant line. 3. Check refrigerant pressure; check and adjust thermostatic expansion
valve. If not functioning properly, check for pressure drop across the filter
drier.
4. Defective low pressure switch. 4. Check calibration of switch.
C. Compressor
starts but cuts out
on high pressure
switch.
1. Refrigerant overcharge. 1. Check subcooling and superheat. (See Paragraph 9.2)
2. Condenser fan motor defective. 2. Check fan motor(s).
3. Condenser coil inlet obstructed or dirty. 3. Check coil and inlet clearances and for possible air recirculation.
4. Air or non-condensables in system. 4. Check high side equalized pressure reading with equivalent outdoor
temperature.
5. Defective high pressure switch. 5. Check calibration of switch.
6. Restriction in discharge or liquid line. 6. Check refrigerant line pressures, check thermostatic expansion valves.
D. Compressor
cuts out on
thermal overload.
1. Low voltage. 1. Check voltage.
2. Sustained high discharge pressure. 2. Check running amperage and conditions described in H.
3. High suction and discharge pressures. 3. Check thermostatic expansion valve setting. Check for non-
condensables in the system.
4. Defective compressor overload. 4. If compressor is hot, allow compressor to cool for two hours. Recheck
for open circuit.
5. Compressor operating in reverse. 5. Switch the 3 phase line voltage wiring connections.
6. Improper refrigerant charge. 6. Check subcooling and superheat. (See Paragraph 9.2)
7. Bearings or pistons too tight. 7. Check for low oil level.
8. Allow time for compressor to cool. 8. Check dome temperature of the compressor.
□
S tep 12. (Select the procedure that applies.) (cont’d)