Return-Air Filters; Outdoor-Air Inlet Screens; Compressor Mounting; Internal Wiring - Carrier 48JC04-06 Service And Maintenance Instructions

WARNING
If the information in this manual is not followed exactly, a
fire or explosion may result causing property damage, per-
sonal injury or loss of life.
Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any
phone in your building.
• Immediately call your gas supplier from a neighbor's
phone. Follow the gas supplier's instructions.
• If you cannot reach your gas supplier, call the fire
department.
Installation and service must be performed by a qualified
installer, service agency or the gas supplier.
AVERTISSEMENT
RISQUE D´INCENDIE OU D´EXPLOSION
Si les consignes de sécurité ne sont pas suivies à la lettre,
cela peut entraîner la mort, de graves blessures ou des dom-
mages matériels.
Ne pas entreposer ni utiliser d´essence ni autres vapeurs ou
liquides inflammables à proximité de cet appareil ou de tout
autre appareil.
QUE FAIRE SI UNE ODEUR DE GAZ EST DÉTECTÉE
• Ne mettre en marche aucun appareil.
• Ne toucher aucun interrupteur électrique; ne pas
utiliser de téléphone dans le bâtiment.
• Quitter le bâtiment immédiatement.
• Appeler immédiatement le fournisseur de gaz en
utilisant le téléphone d´un voisin. Suivre les
instructions du fournisseur de gaz.
• Si le fournisseur de gaz n´est pas accessible, appeler le
service d´incendie.
L´installation et l´entretien doivent être effectués par un in-
stallateur ou une entreprise d´entretien qualifié, ou le four-
nisseur de gaz.

Return-Air Filters

Ensure correct filters are installed in unit (see Appendix B —
Physical Data). Do not operate unit without return-air filters.

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
remove compressor hold down bolts.

Internal Wiring

Check all electrical connections in unit control boxes. Tighten
as required.

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 compres-
sor discharge line. Be sure that caps on the ports are tight.

Compressor Rotation

EQUIPMENT DAMAGE HAZARD
Failure to follow this caution can result in premature wear and
damage to equipment.
Scroll compressors can only compress refrigerant if
rotating 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.
48JC units have scroll compressors, it is important to be certain
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 posi-
tion and fan switch at AUTO. position. Adjust thermostat to a
setting below room temperature. Compressor starts on closure
of contactor.
Check unit charge. Refer to Refrigerant Charge section on
page 12.
Reset thermostat at a position above room temperature.
Compressor will shut off. Evaporator fan will shut off after a
30-second delay.
To shut off unit, set system selector switch at OFF position.
Resetting thermostat at a position above room temperature
shuts unit off temporarily until space temperature exceeds ther-
mostat setting.

Main Burner

Main burners are factory set and should require no adjustment.
To check ignition of main burners and heating controls, move
thermostat setpoint above room temperature and verify that the
burners light and evaporator fan is energized. Check heating
effect, then lower the thermostat setting below the room tem-
perature and verify that the burners and evaporator fan turn off.
When replacing unit orifices, order the necessary parts through
RCD. See the High Altitude Gas Conversion Kit Gas Heat-
ing/Electric Cooling 3 to 15 Ton Small Rooftop Units Accessory
LP (Liquid Propane) Installation Instructions for details.

Heating

1. Purge gas supply line of air by opening union ahead of the
gas valve. If gas odor is detected, tighten union and wait
5 minutes before proceeding.
45
CAUTION