Maintenance / Service And Troubleshooting - Modine MDB Série Manuel D'installation Et De Maintenance

maintenance / service and trouBleshootinG

care of heater for extended shutdown Periods
If the unit is to be shut down for an extended period of time,
the following precautions should be followed.
1. Turn off all manual shutoff valve(s) in the gas train of the
unit, and in the gas supply line to the unit.
2. Turn off the electric supply to the unit at the unit's
disconnect. Lock the disconnect to prevent tampering.
3. If the unit is supplied with filters, remove and store the
filters.
4. Protect outside air openings to prevent the unit from being
soiled.
service and trouBleshootinG
table 42.1 - service & troubleshooting
trouble
A. Power Failure
B. Dampers Won't Operate
C. Motor Failure
D. Blower Not Turning
E. No Burner Operation
If the preceding service diagnostics do not solve your problem, contact your local Modine Manufacturing sales representative for further assistance.
Please be sure to have the complete model number and serial number from the unit's rating plate available before calling for service
42
When servicing or repairing this equipment, use only
factory-approved service replacements parts. A complete
replacement parts list may be obtained by contacting the
factory. Refer to the rating plate on the unit for complete unit
model number, serial number, and company address. Any
substitution of parts or controls not approved by the factory
will be at owner's risk.
Do not reuse any mechanical or electrical component which
has been wet. Such component must be replaced.
To check most of the Possible Remedies in the troubleshooting
guide listed in Table 42.1, refer to the applicable sections of the
manual.
Possible cause
1. Disconnect not turned on.
2. Blown fuses.
3. Main to unit disconnect not on.
1. Disconnect not turned on.
2. Blown fuses.
3. Main to unit disconnect not on.
4. Failed damper motor.
5. Loose wiring to motor.
6. Damper linkage binding.
1. Disconnect not turned on.
2. Blown fuses.
3. Main to unit disconnect not on.
4. Failed motor.
5. Loose wiring to motor.
6. Starter fuses blown.
7. Motor overloaded.
8. Improper supply voltage.
9. Motor overheating.
1. See Problems "A" and "C"
2. Broken drive belt(s).
3. Bearings seized.
4. Improper supply voltage.
1. See Problems "A" thru "D"
2. Damper end switch not functioning.
3. Failed air flow switch.
4. Loose wiring connection at air proving.
5. No pilot.
6. Pilot not proving.
7. Flame safeguard in lockout mode.
8. High limit tripped.
9. Too high or low gas pressure.
10. Failed control transformer.
11. Blown control transformer fuse.
12. Failed or malfunctioning main gas
valve(s).
13. Faulty or failed freeze stat or inlet on/off stat.
14. Failed safeguard control.
15. Airflow too low, low airflow proving
switch is open.
16. Airflow too high, high airflow cutoff switch
is open.
7-500.10
WarninG
caution
imPortant
Possible remedy
1. Turn to disconnect.
2. Check and replace.
3. Turn on power at main.
1. Turn on disconnect.
2. Check and replace.
3. Turn on power at main.
4. Check and/or replace.
5. Check and tighten.
6. Check and clear.
1. Turn on disconnect.
2. Check and replace.
3. Turn on power at main.
4. Check and/or replace.
5. Check and tighten.
6. Check and/or replace.
7. Check for proper speed.
8. Check and correct.
9. Check firing rate of unit.
1. See Problems "A" and "C"
2. Check and replace.
3. Check and replace.
4. Check and correct.
1. See Problems "A" thru "D"
2. Check and/or replace.
3. Check and/or replace.
4. Check and tighten.
5. See Problem "F"
6. See Problem "F"
7. Check and reset.
8. Check and/or replace.
9. Check pressure switches
and gas pressure.
10. Check and/or replace.
11. Check and/or replace.
12. Check and/or replace
13. Check and/or replace.
14. See vendors instructions
shipped with unit.
15. Check for reason of insufficient airflow
and current.
16. Check for reason of excessive airflow
and correct
.