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Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
Chapter 3 Start-Up
3.1 Check-Out of Cooling Cycle
Important: Be sure that the crankcase heater (if used) has been energized for at least 24 hours
before starting the unit(s). Double-check all electrical connections before applying power. All air
conditioners with scroll compressors running on 3Ø power must be checked for proper rotation
during the initial start-up. Please refer to Section 2.8 for determining if the 3Ø compressors are
rotating correctly. Incorrect rotation can damage the compressor and is not covered by the warranty
Procedure
:
1. Set the cooling set point temperature on the wall thermostat to a point
higher
than the ambient
temperature. Set the heating set point temperature to a temperature that is
lower
than the ambient.
2. Set the thermostat system switch in the AUTO position. Nothing should operate at this time.
3. Set the time delay in the control box to three minutes. See Section 1.6.
4. Slowly lower the thermostat's cooling set point temperature until the switch closes. The indoor fan
should operate.
Once the indoor fan turns on, allow approximately three minutes for the compressor to start.
5. To stop cooling, slowly raise the thermostat cooling set point to a temperature higher than the
ambient.
If the unit fails to operate, refer to the troubleshooting information in Chapter 4.
Follow the same procedure for additional units.
NOTE:
The fan purge allows the indoor fan to run for approximately 90 seconds after the compressor
is off. This operation provides a small improvement in system rated efficiency.
3.2 Check-Out of Heating Cycle
Procedure
: (Applies only to units with resistance elements)
1. Raise the heating set point temperature to a setting which is higher than the ambient temperature.
The fan and electric heat should immediately cycle on.
2. Move the system switch to the "OFF" position. All functions should stop.
Chapter 4 Troubleshooting
4.1 Overview
The middle front panel provides access to the electrical/control box and to the filters. This panel has hinges
on the left and right hand side. This panel should ONLY be opened by using the two hinges on the left
side
OR
the two hinges on the right side.
NEVER OPEN ALL FOUR HINGES SIMULTANEOUSLY
.
If all four hinges are opened simultaneously, the front panel will drop and may cause serious injury
and damage the panel.
DANGER
NEVER open all four hinges simultaneously. The panel should ONLY be opened by using
the two hinges on the left side OR the two hinges on the right side.
