HER Installation and Service Manual

2-525.6
GENERAL MAINTENANCE / TROUBLESHOOTING
WARNING CAUTION
Do not reuse any electrical component which has been wet.
Such component must be replaced.
NOTE: To check most of the Possible Remedies in the
trouble-shooting guide listed in Table 7.1, refer to the
applicable sections of the manual.
Table 7.1 - Troubleshooting
Replacement parts can be obtained from Modine by submitting
the model number, power code, control code and serial number
shown on the rating plate attached to the unit, along with a
description of the part.
PROBLEM POSSIBLE CAUSE(S) REMEDY
1. a. Turn on switch or thermostat.
b. Move thermostat to higher setting.
c. Replace fuse or reset disconnect switch.
2. Replace fuses.
3. Check wiring and connections. Refer to diagram inside
control panel.
4. Check continuity with volt-ohmmeter. Replace defective
part if necessary.
5. Check secondary voltage with voltmeter. Replace if
necessary.
1. a. Not enough air volume over elements. Louvers must
be open at least 45°.
b. Check motor rpm against nameplate rating. Replace
motor if speed is too slow.
c. Defective limit control. Check wiring and connections.
Check continuity through control. Replace if necessary.
2. Change switch position.
3. Check all wiring and connections. See diagram inside
control compartment.
4. Replace element fuses.
1. a. Check for loose electrical connections. Check wiring
with diagram in control compartment.
b. Repair or replace burned out defective motor.
c. Voltage too high or too low. Check voltage with
voltmeter.
2. Check for continuity with volt-ohmmeter. Replace if
necessary.
3. Check all wiring and connections. See diagram inside
control compartment.
1. Add more units or increase size of units.
2. Lower units.
3. Repair, replace motor or reverse fan rotation.
4. Disconnect internal wiring and check element resistance
with ohmmeter.
1. Electric circuit in open position.
2. Blown fuses in control compartment.
3. Defective or incorrect wiring.
4. Defective thermostat or switch.
5. Defective or burned out control
transformer.
1. Power interrupted by overheat control.
2. Summer-winter switch in summer position.
3. Defective or incorrect wiring.
4. Blown element fuses on HER200 and
HER250 w/208 or 240V-3ø power supply.
1. Fan motor failure.
2. Summer-winter switch defective or
improperly wired.
3. Defective or incorrect wiring.
1. Too few units for heat loss.
2. Unit mounted too high.
3. Fan operates backwards.
4. Burned out element.
Routine Unit Maintenance
Under average conditions, it is recommended that unit heaters
be serviced at least once a year and checked out prior to the
heating season. In excessively dirty atmospheres, service
should be performed more often.
1. Disconnect power supply to the unit before performing
any of the following maintenance or inspection procedures
& allow heating elemt of heater to cool.
2. Check all components and wiring inside the unit for firm
connections and/or wear.
3. Tighten fan guard and motor bracket. Check fan for proper
clearance, free rotation, and firm connection to motor shaft.
Clean fan blade with detergent or compressed air.
4. Fan motor is permanently lubricated for normal operation.
Under severe conditions, lubricate with non-detergent
SAE 20 motor oil.
5. Routine cleaning of the unit casing and louvers is recommended
to remove dirt, grease, or corrosive substances that may
damage the finish. Rusted or corroded spots on the louvers
or casing should be sanded and repainted. To remove, push
louvers against retaining coil spring and pull out at opposite
tapered end.
6. Check entire electrical system before every heating season.
Unit does not operate
Fan operates but element
does not heat
Elements heat but fan does
not operate
Insufficient heat
1. When servicing or repairing this equipment, use only
factory approved service replacement parts. A complete
replacement parts list may be obtained by contacting
Modine Manufacturing Company. Parts not approved by the
factory will be at the owner’s risk.
2. Do not operate any heater if it malfunctions. Disconnect
power at service panel and have heater inspected by a
qualified installation and service agency.
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