Troubleshooting Tips - Modine Manufacturing HEX6 Series Installation, Parts, Service, And Maintenance Manual

C.

TROUBLESHOOTING TIPS

1. Heater is not operating.
1.1 Check all fuses in heater control box.
1.2 Check remote disconnect switch and circuit
breaker.
1.3 Check voltage supplied to the heater – refer to
the heater data plate for voltage requirements.
1.4 Check thermostat by turning it and check
continuity with a multimeter.
1.5 Check the condition of the disconnect switch if
the heater is so equipped. Measure continuity
through the disconnect by engaging the switch.
1.6 Verify that there is a jumper wire present
between terminals 5 and 6 on the terminal
block located in the control box.
1.7 Check that internal breaker has not opened. If
internal breaker has opened it is indication that
an over-temperature event has occurred. Heater
must be thoroughly evaluated by qualified
personnel to ensure it is in proper working order
before resetting this device.
2. Contactor is chattering.
2.1 Check supply voltage.
2.2 Check wiring connections. Tighten all loose
electrical connections.
2.3 Check thermostat for continuity (See 1.4,
page 6). If thermostat does not break
continuity replace thermostat.
3. Contactor is burned or welded.
3.1 Check the contactor for burn marks and
blackening. Replace the contactor.
3.2 Check incoming power to the heater to ensure
there are no voltage fluctuations.
4. Heat exchanger is dirty.
4.1 Clean the heat exchanger using compressed air.
5. Pressure Relief Devices.
5.1 If there are signs that the Pressure Relief Device
has released fluid, Pressure Relief Device
indicator is broken, blackening around the
Pressure Relief Device exit hole, or there are
fluid stains visible on the top louver, shut the
unit down immediately. Activation requires the
heater be removed from service for inspection
by authorized personnel. Do not circumvent the
overpressure devices to operate the heater. Lock
out/ tag out heater according to site procedures.
5.2 Check for restricted air flow, bad motor, broken
thermostat or malfunctioned high limit.
5.3 There is a secondary Pressure Relief Device to
insure safety of the unit.
5.4 If the secondary pressure relief device has
opened, shut the unit down immediately. This
is a single use device. Activation requires the
6 6
heater be removed from service for inspection
by authorized personnel. Do not circumvent the
overpressure device to operate the heater. Lock
out/ tag out heater according to site procedures.
6. Heater is cold on top and warm on bottom.
6.1 The core may have lost its vacuum. Check the
pressure relief devices for signs of loss of fluid
and verify that the pressure relief devices label
indicator is not broken. If pressure relief devices
has released, send the unit in for repair or
replace the core.
6.2 If the Pressure Relief Device does not indicate
loss of fluid, the heater should operate normally.
6.3 The ambient temperature may be too low. If
the ambient temperature is very cold the top of
the core will be colder than the bottom – this is
normal.
7. Unit cycles on high limit – unit turns on and turns off
within less than 5 minutes.
7.1 Check and see if the pressure relief devices has
released fluid. Core may have lost most or all of
its fluid. If Pressure Relief Device has released,
the unit requires inspection by authorized
personnel.
7.2 The core may be dirty, fan may not be working
or may be turning the wrong direction (the fan
must rotate clockwise as seen from the front
of the unit) objects may be stuck in the heat
exchanger for drying or warming up – remove
any items from the exchanger.
8. The Ground Fault Interrupter (GFI) trips on the main
panel, or heater blows fuses.
8.1 Check that you have a fuse of the proper
amperage rating.
8.2 Check the pressure relief device for signs of loss
of fluid and verify that the pressure relief device
label is not broken.
8.3 If condition is not observable, send heater in for
repair.
8.4 Heat exchanger needs to cool in order to
engage switch to "ON" postion.
8.5 Contact factory if further assistance is needed.
9. The fan is turning but very little air comes from the
front of the heater.
9.1 Check fan rotation and ensure that the fan turns
clockwise as seen from the front of the heater.
Refer to the Installation section below for more
information.
9.2 Check motor winding resistance and verify that
they are within tolerance.
9.3 Check fan blade set screws to ensure fan blade
is not loose on the motor shaft.