Owner’s Manual -
CMA12-48SD
14
4/2014
INITIAL START-UP & CHECkS
Operation of the unit is automatic and will provide
cooling depending on the setting of the thermostat.
IMPORTANT!
All panels must be installed, main power turned
on and the thermostat properly connected before
operating the unit.
1. System check - set thermostat system switch to
“Off” position and fan switch to “Auto” position.
Turn the power supply breaker on.
2. Set the fan switch to “On,” blower should
operate.
3. Return the fan switch to “Auto”. Blower should
shut off. Set the system switch to “Cool” and
lower thermostat set point to coldest setting.
The compressor, condenser fan, and evaporator
blower should all come on. Cool air will be
supplied after a couple of minutes of run time.
4. Proceed to the “FIELD CHARGING” section of
these instructions.
FIELD CHARGING
Unit performance, efficiency, and life depends,
to a large extent, on a proper system charge.
Time spent on getting the charge right at start-up
will payoff in the long run. Operating conditions
such as voltage, air flow, evaporator coil size,
and indoor and outdoor temperature and humidity
all have an effect on the system pressures and
superheat conditions.
Charge must be added for the interconnecting
tubing.
Use of piston-style metering device is
typical. Where TXVs are necessary due to AHRI-
match or performance-related applications, a
15% bleed-type TXV is required.
These units
should be critically charged to ensure proper
performance. Some systems may require
additional charging of refrigerant, depending on
line set lengths.
FINAL INSPECTION
Do a final visual inspection of the entire installation
and complete any final details and clean up.
Review Unit Operation with the homeowner/user.
The pressure/temperature chart can be used as a
reference to ensure performance.
2XWGRRU$PELHQW7HPSHUDWXUH963UHVVXUH
2XWGRRU7HPSHUDWXUH
1RWH
³,'7´ ,QGRRU7HPSHUDWXUH
³2'7´ 2XWGRRU7HPSHUDWXUH
5HPRYHUHIULJHUDQWLIWKHSUHVVXUHLVDERYHWKHFKDUWYDOXH
$GGUHIULJHUDQWLIWKHSUHVVXUHLVEHORZWKHFKDUWYDOXH
36,
R(oz): Additional refrigerant to be charged
L(ft): The length of the liquid pipe
T(oz): The quantity of the charged refrigerant
per additional foot
Charging by Length of Pipe
Your condensing unit is pre-charged for the
evaporator coil and 25 ft. of refrigerant line set.
For lengths over 25 ft. use charging chart and
formula below.
