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Marvair Wall Mount H/P MAA1020H-1048H/MGA1072H I&O Manual
02/2021 Rev.2
b. For units with the optional variable fan speed controller for the GreenWheel
®
ERV exhaust blower, first
measure the air being introduced into the classroom using best industry standards and practices. Adjust
the speed of the intake air GreenWheel ERV blower until the required outside air is being brought into
the classroom.
c. Now measure the exhaust air from the classroom. Adjust the speed of the exhaust air GreenWheel
ERV blower until the required air is being exhausted from the classroom. The exhaust air controller is
located on the lower left side of the GreenWheel ERV assembly. Access to the exhaust air controller
is through the return air grille. It is usual practice to pressurize the classroom by exhausting slightly
less air than is being brought into the classroom.
Evaporator Variable Fan Speed Controller (Optional)
Indoor evaporator fan controller is accessed through the return air opening. The controller is located on the
GreenWheel ERV assembly on the air separation box in a 2” x 4” “J” box.
Note: Sufficient airflow is required for proper operation of the unit.
Troubleshooting
4.1 Overview
A comprehensive understanding of the operation of the Marvair
®
Heat Pump is a prerequisite to
troubleshooting. Please read the Chapter 1 for basic information about the unit.
Marvair Heat Pumps are thoroughly tested before they are shipped from the factory. However, it is possible
that a defect may escape undetected, or damage may have occurred during transportation. However, the
great majority of problems result from installation errors.
If you experience difficulties with the Heat Pump, please review the installation steps in Chapter 2.
Much time can be saved by taking a thoughtful and orderly approach to troubleshooting. Start with a
visual check - are there loose wires, crimped tubing, missing parts, etc? Begin deeper analysis only after
making this initial inspection.
The troubleshooting information in this manual is basic. The troubleshooting section contains problem
/ solution charts for general problems, followed by a compressor section.
Not every problem can be anticipated. If you discover a problem that is not covered in this manual, we
would be very grateful if you would bring it to the attention of our service department for incorporation
in future revisions.
As always, please exercise caution and good judgement when servicing your Heat Pump. Use only safe
and proven service techniques. Use refrigeration goggles when servicing the refrigeration circuit.
The refrigerant circuit has hot surfaces, and the electrical voltages inside of the unit may be hazardous or
lethal. SERVICE MAY BE PERFORMED ONLY BY QUALIFIED AND EXPERIENCED PERSONS.
WARNING
The refrigerant circuit has hot surfaces, and the electrical voltages inside of the unit
may be hazardous or lethal. SERVICE MAY BE PERFORMED ONLY BY QUALIFIED
AND EXPERIENCED PERSONS.
