Specifications

ModPac II, 9/09-15

Start-Up

Important: If your unit has a crankcase heater be sure that the crankcase heater has been energized

for at least 24 hours prior to start-up of the unit. Double check all electrical connections before

applying power. Various thermostats can be used to control the air conditioner. The thermostat

may have a fan switch with an Automatic and On positions, a system switch with Heat, Cool, and

Off positions. The spec sheets have detailed description of the various Marvair

thermostats.

Since other thermostats or remote control systems may be used, the following procedures should

be viewed as guidelines for standard thermostats with system and fan switches.

3.1 Check-Out of Cooling Cycle

Procedure:

1. Set the cooling temperature on the wall thermostat to a point higher than the ambient

temperature. Set the heating 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. Slowly lower the thermostat's cooling 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.

Note that the outdoor fan may not come on immediately, because it is cycled by refrigerant

pressures.

Alternately, when outdoor conditions are lower than the set point, a source of heat such as a hair

dryer can be directed on the air temperature sensor to simulate warmer conditions, which will

bring on mechanical cooling and start the compressor.

4. To stop cooling, slowly raise the thermostat cooling 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: Blower Time Delay Relay (BTR) allows the indoor fan to run for approximately 90

seconds after the compressor is off. This operation provides a small improvement in system

efciency.

3.2 Check-Out of Heating Cycle

Procedure: (Applies only to units with resistance elements.)

1. Raise the heating 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.

IMPORTANT