Operation; Operating Sequence - Modine Manufacturing AMP Installation And Service Manual

OPERATION

WARNING
The heater must be properly installed before use.
IMPOR T ANT
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 all electrical connections to be sure they are secure,
and in accordance with the wiring diagram.
2. Check firmness of unit suspension. Tighten all fasteners, if
necessary.
Safety Devices
The overheat controls, mounted on the bottom of the control
section (See Figure 6.1), will interrupt power to the unit
contactor in the event of overheating. The limit nearest the fan
scroll is a single-pole, single-throw switch, with an automatic
reset. The limit nearest the control panel opening is a single-
pole, single-throw switch, with a manual reset. If either of
these limits is tripped, the red overheat alarm indicator on the
front of the unit will illuminate (See Figure 6.2). During this
state, power to the elements will be disrupted, but the controls
will permit the motor to continue operation and cool the
heater. The overheat controls should operate only when
something is wrong with the unit or space temperature.
When this control operates, correct the difficulty
immediately or serious and permanent damage may
result. If the Overheat Alarm indicator light is illuminated, it is
recommended that the unit be disconnected from power at the
breaker until the unit can be inspected and the issue resolved.
Do not continue to use heater if it repeatedly overheats to cycle
the safety thermal limit.
The motor for the blower wheel 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. In the event of a complete motor failure,
the manual limit will trip and prevent the elements from heating/
cycling. Following motor servicing/replacement, the manual
reset button must be pressed to reset the switch prior to the
elements functioning again.
6 6
Initial Start-Up
1. Set thermostat above room temperature.
2. Turn on power to the unit.
3. Run the unit through several cycles by raising and lowering
the thermostat setting to assure proper sequence of
operation.

Operating Sequence

The operation of this electric unit heater is governed by
a microprocessor control board which is controlled by a
thermostat. The board completes the electric circuit to the
heating elements when the thermostat "calls" for heat. The
green 'Heating Mode' indictor light on the front of the unit will
illuminate when this occurs. The fan motor is also activated
shortly after the thermostat "calls" for heat. When the thermostat
is satisfied, the control board opens the circuit to the heating
elements. There is a cooldown period where the fan will
continue to operate after the elements are de-energized to
dissipate the remaining heat from the elements before fully
shutting off.
Figure 6.1 - Control Board
Figure 6.2 - Indicator Lights
2-529.0