Owner Manual

Page 15 mrcool.com
Unit Installation
CAUTION
1. Ensure that all power supply is disconnected prior to installing the heater kit.
2. A means of strain relief and conductor protection must be provided at the supply wire entrance into
cabinet.
3. Only use copper conductors.
4. Installation must follow national electric code and other applicable codes.
5. If this appliance is installed in an enclosed area such as a garage or utility room with any carbon
monoxide producing appliance, ensure the area is properly ventilated to the outside.
6. A filter dryer is recommended for installation based on nominal tonnage.
1) Refer to the Table below for the appropriate optional
heater kit.
2) Check for any physical damage; do not install damaged
heater kit.
3) Remove the upper access panel from air handler.
4) Remove cover plate from air handler.
5) Slide the heater kit into the slot and secure element
plate with previously removed screws.
6) Insert power leads into the circuit breaker lugs or
stripped red and black wires (for heater kit without
circuit breaker) and tighten.
7) Connect ground wire to ground lug.
8) Break out appropriate area of the plastic circuit
breaker cover on the access panel of the air handler.
Knock off the holes according to the actual installation
number and circuit breaker positions. If a circuit
breaker is not installed, do not knock off the holes;
otherwise, electric shock may occur.
9) Replace access panel and check operation.
10) Connect power cords and thermostat wires.
Cover Plate
Heater Kit
Circuit Breaker
Bolt
Fig 2.7
IMPORTANT
You must use a compatible heat kit listed in the above chart. Using an incorrect size, could cause
the unit to overheat and/or cause equipment damage.
MHK15U
MHK20U
Circuit breaker, 15kW heat strip
Circuit breaker, 20kW heat strip
Kit #. Description
Compatible Heat Kits for Model# MDUI18048/MDUI18060
The thermostat wires
get in through this hole.
Thermostat wires