HER Installation and Service Manual

2-525.6
5
OPERATION
Figure 5.1 - Exposed Side of Electric Unit Heater
3
2
1
1. Heating Element*
2. Adjustable air deflectors
3. Overheat control**
IMPORTANT
Start-up and adjustment procedures must be performed by a
qualified service agency.
Prior to Operation
Although this unit has been inspected and tested at the factory,
the following procedures should be performed to assure proper
on-site operation:
1. Check fan clearance. Fan should not contact casing when
spun by hand.
2. Check all electrical connections to be sure they are secure,
and in accordance with the wiring diagram.
3. Check firmness of unit suspension. Tighten all fasteners,
if necessary.
4. Make sure fuses are installed in units that require them.
Safety Devices
The overheat control, mounted on the right inner side panel
for HER 30-50 and left inner side panel for HER 75-250 (See
Figure 5.1), will interrupt power to the unit contactor in the event
of overheating. It is a single-pole, single-throw switch, with an
automatic reset. The switch will permit the motor to continue
operation and cool the heater while power to the elements
is interrupted. This overheat control should operate only
when something is seriously wrong with the unit. When
this control operates, correct the difficulty immediately or
serious and permanent damage may result.
The motor for the circulating air fan has internal thermal
overload protection. If for any reason the motor overheats,
the thermal protector will shut it off. The motor will restart
automatically when it has cooled.
Initial Start-Up
1. Set thermostat above room temperature.
2. Turn on power to the unit.
3. Adjust the air deflector blades for desired heat distribution.
All horizontal blades should be kept open a minimum of 45°
as measured from vertical.
4. Run the unit through several cycles by raising and lowering
the thermostat setting to assure proper sequence of
operation.
Operating Sequence
The operation of Modine electric unit heaters is governed by
an electrical contactor which is controlled by a thermostat.
The contactor completes the electric circuit to the heating
elements when the thermostat “calls” for heat. The fan motor is
also activated when the thermostat “calls” for heat. When the
thermostat is satisfied, the fan motor stops and the contactor
opens the circuit to the heating elements.
* Heating Elements are flipped in HER 30 and HER 50.
** Overheat Control is located on opposite side for HER 30 and HER 50
WARNING
The heater must be properly installed before use.