Modine Manufacturing MPR Series Installation And Service Manual page 59

SERVICE & TROUBLESHOOTING - CONTINUED
Table 59.1 - Troubleshooting (Continued)
Trouble Possible Cause
F. Compressor(s) Do 1. See Problems "A" and "B"
Not Operate
2. Controls are in Unoccupied mode
3. Ambient lockout
4. Low pressure lockout
5. High pressure lockout
6. Inter-stage delay
7. Airflow proving switch not closing
8. Thermostat not calling for cooling
9. Drain pan float switch open
G. Compressor(s) Do 1. Supply air temperature not satisfied
Not Cycle Off
H. Dampers Do Not 1. See Problem "A"
Operate
2. Failed damper motor(s)
3. Loose wiring to damper motor(s)
4. Controls are in Unoccupied mode
5. Ambient lockout
I. Electric Heat Not 1. See Problem "A"
Functioning
2. See Problem "D"
3. Thermostat not calling for heat
4. Limit switches are open
5. Overload relay is tripped
6. Failed heat modules
J. Gas Heat Not 1. See Problem "A"
Functioning Properly
2. See Problem "D"
3. Thermostat not calling for heat
4. Limit switches are open
5. Main gas supply not turned on
6. Air in gas line
7. Loose wiring to ignition controls or gas valves
8. Failed ignition controller or gas valve
9. Failed flame sensor
10. Improper supply air temperature sensor installation
11. Flame rollout or flashback
12. Not enough heat
13. Too much heat
14. Clogged condensate drain line (condensing or hybrid
condensing heat option only)
Possible Remedy
1. See Problems "A" and "B"
2. Wait for Occupied mode or override
3. Check and wait or override
4. Check and wait or override
5. Check and wait or override
6. Check and wait or override
7. Check and correct
8. Check and wait or override
9. Check switch, check drain line (pan, trap, piping) for proper
drainage, and verify trap is primed with water
1. Compressors will remain on until the supply air setpoint is
satisfied
1. See Problem "A"
2. Check and replace
3. Check and tighten
4. Wait for Occupied mode or override
5. Check and wait or override
1. See Problem "A"
2. See Problem "D"
3. Check and wait or override
4. Check and correct
5. Check and correct
6. Check and replace
1. See Problem "A"
2. See Problem "D"
3. Check and wait or override
4. Check and correct
5. Check and correct
6. Purge per instructions
7. Check and tighten
8. Check and replace
9. Check and replace
10. Check and correct
11a. Main pressure too high (correct to 14" W.C. max)
11b. Orifice too large (verify they match the serial plate)
11c. Manifold pressure too low (reset)
12a. Unit cycling on high limit (check airflow)
12b. Main pressure too low (must be 6" W.C. minimum for
Natural Gas or 11" W.C. for Propane (LP) Gas)
12c. Unit undersized for conditions
12d. Improper supply air temperature sensor installation
13a. Manifold pressure too high (correct to 3.5" W.C.)
13b. Defective or improperly wired controls
14. Check condensate drain line, clear as needed
MCP15-500.9
59