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58
UNIT PREPARATION
Ensure the unit has been installed in accordance with installation
instructions and applicable codes.
RETURN-AIR FILTERS
Ensure the correct filters are installed in the unit (see Appendix B).
Do not operate unit without return-air filters in place.
OUTDOOR-AIR INLET SCREENS
Outdoor-air inlet screen must be in place before operating unit.
COMPRESSOR MOUNTING
Compressors are internally spring mounted. Do not loosen or re
-
move compressor hold down bolts.
INTERNAL WIRING
Check all electrical connections in unit control boxes. Tighten as
required.
COMPRESSOR ROTATION
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 pressure
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 apply lockout/tag-out
procedures.
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.
REFRIGERANT SERVICE PORTS
Each unit system has two
1
/
4
-in. SAE flare (with check valves)
service ports: one on the suction line, and one on the compressor
discharge line. Be sure that caps on the ports are tight.
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 to AUTO. position. Adjust thermostat to a setting be
-
low room temperature. Compressor starts on closure of contactor.
(Second stage of thermostat will energize Circuit 2 contactor, start
Compressor 2.)
Check unit charge. Refer to Refrigerant Charge section.
Reset thermostat at a position above room temperature. Compres
-
sor will shut off. Evaporator fan will shut off after a 60 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 to the OFF position.
Resetting thermostat at a position above room temperature shuts
the unit off temporarily until space temperature exceeds thermo
-
stat 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 (both com
-
pressors 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.
Shut unit off - set system selector switch to the OFF position. Re
-
setting thermostat at a position below room temperature temporar
-
ily shuts unit off until space temperature falls below thermostat
setting.
VENTILATION (CONTINUOUS FAN)
Set fan and system selector switches at ON and OFF positions, re
-
spectively. Supply fan operates continuously to provide constant
air circulation.
START-UP, PREMIERLINK CONTROLS
START-UP, RTU-OPEN CONTROLS
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.
NOTICE: SET-UP INSTRUCTIONS
All set-up and set point configurations are factory set and field-
adjustable.
Refer to the PremierLink Installation, Start-Up and Configura
-
tion Instructions for specific operating instructions for the con
-
troller. Have a copy of this manual available at unit start-up.
NOTICE: SET-UP INSTRUCTIONS
Refer to the following manuals for additional installation, wir
-
ing and troubleshooting information for the RTU-OPEN Con
-
troller.: “Controls, Start-up, Operation and Troubleshooting In
-
structions,” “RTU Open Installation and Start-up Guide” and
“RTU-Open Integration Guide”. Have a copy of these manuals
available at unit start-up.
Summary of Contents for WeatherMaker 50TCQ 17-24 Series
Page 35: ...35 Fig 53 RTU Open Overlay for Economizer Wiring ...
Page 36: ...36 Fig 54 VFD Overlay for W2770 Controller Wiring ...
Page 68: ...68 Fig B 50TCQD17 24 Control Wiring Diagram APPENDIX D WIRING DIAGRAMS ...
Page 69: ...69 Fig C 50TCQD17 24 Power Wiring Diagram 208 230 3 60 Units APPENDIX D WIRING DIAGRAMS ...
Page 70: ...70 Fig D 50TCQD17 24 Power Wiring Diagram 460 3 60 575 3 60 Units APPENDIX D WIRING DIAGRAMS ...
Page 71: ...71 Fig E RTU Open Overlay APPENDIX D WIRING DIAGRAMS ...
Page 72: ...72 Fig F PremierLink Overlay APPENDIX D WIRING DIAGRAMS ...