Kees MUA TEMPERED MAKE-UP AIR UNITS User Manual

KEES, INC.

Products for Food Service & Sheet Metal Industry

400 S. INDUSTRIAL DRIVE - P.O. BOX L - ELKHART LAKE, WISCONSIN 53020 - [phone] - FAX [phone]

Electric Heater Instructions

WARNING! Electrical shock hazard! Disconnect all power sources before doing any
work on the unit.

General:
The requirements and practices described below are based on the National Electric Code and the Space Heating
Standard of the Underwriters Laboratories Inc. (UL). Although UL requirements are uniform throughout the
country, local electrical codes may deviate from the National Electric Code; therefore, local inspection authorities
should be consulted regarding local requirements.

Electrical Wiring Instructions:

1. Separate circuits are required for the make-up air unit and the heater. The required minimum size of
supply conductors is marked at the field wiring terminals within the heater control box.

2. Use the wiring diagram supplied with the heater as a guide in correlating field wiring with the heater
internal wiring.

3. All field wiring to the heater must meet the requirements of the National Electric Code (NEC) and any
other applicable local or state codes.

4. Wiring to the heater must be rated for 75°C minimum.

5. If a motor control center is included with the make-up air unit, the fan is interlocked to the control circuit
by the factory so the electric heater is not on unless the fan is on. If the motor control center is not
included then this must be done in the field.

6. If the heater does not have a built-in disconnect switch, then a remote disconnect provided by others
must be installed in accordance with the NEC, Article 424-65.

7. If included, the step controller is pre-wired with the KW divided equally among the steps.

8. If included, the duct thermostat must be placed in the blower discharge to monitor the heated air.

Sequence of Operation:

1. Make-up air unit is started.

2. The step controller is allowed to regulate the heat if the following safety features are met:

fan interlock made

-

airflow switch made

-

automatic high temperature limit not tripped

-

manual high temperature limit not tripped

-

3. Above the temperature setpoint none of the elements are energized. As the temperature falls below the
setpoint the first step is energized then additional ones if the setpoint is not met.

4. Unnecessary cycling is avoided by temperature and time delays programmed into the controller.

KEES, INC.

Products for Food Service & Sheet Metal Industry

400 S. INDUSTRIAL DRIVE - P.O. BOX L - ELKHART LAKE, WISCONSIN 53020 - [phone] - FAX [phone]

Direct Expansion (Dx) Coil Instructions

Application Recommendations:

1. Piping should be in accordance with accepted industry standards. Pipework should be supported
independently of the coils. Undue stress should not be applied at the connection to coil headers.

2. The condensate drain pipe should be sized adequately to ensure the condensate drains properly.

3. When connecting suction and liquid connections make sure the coil is free from all foreign material.
Make sure all joints are tight and free of leakage.

4. KEES, Incorporated does not supply compressor or condensing units. Contact your compressor
and/or condenser manufacturer for further instruction on Dx coil installation and operation.

Maintenance Instructions:

1. Filters upstream of the coil should be checked regularly for dirtiness and clogging. If the filters are
dirty, they should be cleaned or replaced. It is important that the coils stay clean to maintain
maximum heat transfer capability.

2. Coils must be clean to obtain maximum performance. Check once a year under normal operating
conditions and, if dirty, brush or vacuum clean. Soiled fins reduce the capacity of the coil, demand
more energy from the fan, and create an environment for odor and bacteria to grow and spread
through the conditioned zone. High pressure water (700 Psi or less) may be used to clean coils with
fin thickness over 0.0095 inches thick.
to determine if the fins will withstand the spray pressure.

TEST THE SPRAY PRESSURE

over a small corner of the coil

For coils with fragile fins or high fin density, foaming chemical sprays and washes are available. Many
coil cleaners contain harsh chemicals, so they must be used with caution by qualified personnel only.
Care must be taken not to damage the coils, including fins, while cleaning.

are sharp.

3. Drain pans in any air conditioning unit will have some moisture in them, therefore, algae and other
organisms will grow due to airborne spores and bacteria. Periodic cleaning is necessary to prevent
this build-up from plugging the drain and causing the drain pan to overflow. Inspect twice a year to
avoid the possibility of overflow. Also, drain pans should be kept clean to prevent the spread of
disease. Qualified personnel should perform cleaning.

CAUTION: Fin edges