Compressor Rotation; Cooling; Heating; Ventilation (Continuous Fan) - Carrier WeatherMaster 50HCQ04-12 Service And Maintenance Instructions

Compressor Rotation

CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution can result in premature wear
and damage to equipment.
Scroll compressors can only compress refrigerant if rotat-
ing in the right direction. Reverse rotation for extended
times can result in internal damage to the compressor.
Scroll compressors are sealed units and cannot be repaired
on site location.
On 3-phase units with scroll compressors, it is important to be cer-
tain compressor is rotating in the proper direction. To determine
whether or not compressor is rotating in the proper direction:
1. Connect service gages to suction and discharge pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge pres-
sure should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge pressure
does not rise to normal levels:
1. Note that the evaporator fan is probably also rotating in
the wrong direction.
2. Turn off power to the unit and install lockout tag.
3. Reverse any two of the unit power leads.
4. Re-energize to the compressor. Check pressures.
The suction and discharge pressure levels should now move to
their normal start-up levels.
NOTE: When the compressor is rotating in the wrong direction,
the unit will make an elevated level of noise and will not provide

cooling.

Cooling
Set space thermostat to OFF position. To start unit, turn on main
power supply. Set system selector switch at COOL position and
fan switch at AUTO position. Adjust thermostat to a setting below
room temperature. Compressor starts on closure of contactor.
(D08–12: Second stage of thermostat will energize Circuit 2 con-
tactor, start Compressor 2.)
Check unit charge. Refer to Refrigerant Charge section on
page 11.
Reset thermostat at a position above room temperature. Compres-
sor will shut off. Evaporator fan will shut off after a 30-second de-
lay if the dip switch for the indoor fan off delay on the Defrost
Control Board (DFB) is set to on.
To shut off unit, set system selector switch at OFF position. Reset-
ting thermostat at a position above room temperature shuts unit off
temporarily until space temperature exceeds thermostat setting.

Heating

To start unit, turn on main power supply.
Set system selector switch to the HEAT position and set ther-
mostat at a setting above room temperature. Set fan to AUTO
position.
First stage of thermostat energizes compressor heating (D08-12:
both compressors will start). Second stage of thermostat energizes
electric heaters (if installed). Check heating effects at air supply
grille(s).
If electric heaters do not energize, reset limit switch (located on
supply-fan scroll) by pressing button located between terminals on
the switch.
To shut unit off, set system selector switch to the OFF position.
Resetting thermostat at a position below room temperature tempo-
rarily shuts unit off until space temperature falls below thermostat
setting.

Ventilation (Continuous Fan)

Set fan and system selector switches at ON and OFF positions,
respectively. Evaporator fan operates continuously to provide
constant air circulation. When the evaporator-fan selector
switch is turned to the OFF position, there is a 30-second delay
before the fan turns off.
START-UP, PREMIERLINK™ CONTROLLER
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal inju-
ry or death.
The unit must be electrically grounded in accordance with
local codes and NEC ANSI/NFPA 70 (American National
Standards Institute/National Fire Protection Association.
Use the Carrier network communication software to start up
and configure the PremierLink controller.
Changes can be made using the ComfortWORKS™ software,
ComfortVIEW™ software, Network Service Tool™, System
Pilot™ device, or Touch Pilot™ device. The System Pilot and
Touch Pilot are portable interface devices that allow the user to
change system set-up and set points from a zone sensor or ter-
minal control module. During start-up, the Carrier software can
also be used to verify communication with PremierLink con-
troller.
NOTE: All set-up and set point configurations are factory set and
field-adjustable.
For specific operating instructions, refer to the literature provided
with user interface software.
SET-UP INSTRUCTIONS
All set-up and set point configurations are factory set and
field-adjustable.
Refer to PremierLink™ Installation, Start-Up and Configu-
ration Instructions for specific operating instructions for the
controller. Have a copy of this manual available at unit
start-up.

Perform System Check-Out

1. Check correctness and tightness of all power and commu-
nication connections.
2. At the unit, check fan and system controls for proper oper-
ation.
3. At the unit, check electrical system and connections of any
optional electric reheat coil.
4. Check to be sure the area around the unit is clear of con-
struction dirt and debris.
5. Check that final filters are installed in the unit. Dust and
debris can adversely affect system operation.
6. Verify that the PremierLink controls are properly con-
nected to the CCN bus.
37
WARNING
NOTICE