19
M
od
Pac 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
efficiency.
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
