Unit Maintenance; Troubleshooting - Carrier 38GL018G Installation Manual

38GL...G / 38YY...G / 38YYS...G
Unit maintenance and troubleshooting

Unit maintenance

The following maintenance operations must be carried out by
qualified personnel.
Cleaning the coil
When necessary, proceed as follows for more careful cleaning of
the coil:
Switch the mains supply OFF.
Remove unit top cover by loosening holding screws and lifting the
cover.
Carefully clean the coil with a vacuum cleaner from inside to
outside.
With the same vacuum cleaner, dust the inside of the fan
compartment and the fan blades. Avoid any damage to the blades
which may cause future vibrations and noise.
Replace the unit cover and tighten the screws.
After long shutdown periods and at commissioning
(for 38YY and 38YYS heat pump models only)
Energize the system by putting the main switch to ON without
starting the unit. (Remote control must be in the OFF position).
Do not disconnect the main switch during the unit operating
season.

Troubleshooting

Compressor and fan of the outdoor unit will not start:
• Unit not energized; check the mains power connections.
• Main switch OFF; check and put to the ON position.
• Main switch fuses have blown; replace.
• Wait for 3 minutes; compressor cycling protection is on.
• HIP and LRPS devices opened (if any): check and eliminate the
cause (refer to "Additional installation instructions").
• Mains voltage too low.
• Electrical connections loose or wrong; check and repair.
Compressor will not start, but outdoor fan is running:
• Electrical connections of compressor loose or wrong; check and
repair.
• Compressor burnt out, seized or protection device on; check for
the cause and replace compressor if necessary.
• Run capacitor faulty; replace.
Compressor starts, but stops due to its overtemperature
protection (other than stops caused by the normal operation
of the thermostat):
• Wrong refrigerant charge (excessive or low) or air or other non
condensable gases in the circuit; drain refrigerant (see note 1),
evacuate and recharge.
• Mains voltage wrong (too high or too low).
• Condenser coil obstructed; remove obstructions.
• Outdoor fan off; check cause and repair.
• Run capacitor faulty; check and replace.
• Refrigerant circuit clogged; check and remove obstructions.
• Reversing valve faulty on heat pump models; replace.
• Expansion device clogged or covered with ice; drain refrigerant
(see note 1), evacuate and recharge.
Compressor runs continuously:
• Unit selected too small for actual air conditioning needs.
• Indoor temperature selection too low (if in cooling) or too high (if
in heating, for heat pump models); check temperature selection.
• Refrigerant charge low; check and add refrigerant.
• Air or other non condensable gases in the circuit; drain
refrigerant (see note 1), evacuate and recharge.
• Obstructions at air intake or dirty indoor unit filters; remove
obstruction or clean filter.
Frequent ice build-up on outdoor coil (during heating with
heat pump units):
• Outdoor fan not working or working incorrectly; check cause and
repair.
• Wrong electrical connections between indoor and outdoor units;
check electrical connections and repair.
• Check defrost end thermostat positioning and connection.
• Outdoor unit fan runs continuously during defrost cycles (heat
pump heating): check connections.
Discharge pressure too high:
• Outdoor coil dirty or obstructed; clean or remove obstructions.
• Unit condenser fan faulty or working incorrectly; replace or
check.
• Refrigerant charge too high; drain some refrigerant (see note 1).
• Air or other non-condensable gases in the circuit; drain
refrigerant (see note 1), evacuate and recharge.
• If installed, the head pressure controller prevents the outdoor fan
motor from reaching its maximum speed.
Check the head pressure controller by connecting the fan
directly. Replace the HPC if necessary.
Discharge pressure too low:
• Refrigerant charge too low; add refrigerant.
• Outdoor coil dirty or obstructed; clean or remove obstructions.
• Indoor unit air filter dirty; clean filter.
Suction pressure too high:
• Refrigerant charge too high; drain some refrigerant (see note 1).
• Reversing valve faulty or internal leak; replace.
Suction pressure too low:
• Refrigerant charge too low; add refrigerant.
• Evaporator coil covered with ice; see the following points.
• Air shortage to the evaporator unit; check and repair and check
indoor unit fan operation.
• Expansion device or suction line clogged: check and repair.
• The outdoor unit fan does not work according to head pressure;
check the controller operation.
• Expansion device clogged or covered with ice; drain some
refrigerant (see note 1), evacuate and recharge.
Outdoor fan cycling due to its overtemperature protection:
• Fan capacitor faulty; replace.
• Electrical connection loose; check connections.
• Fan motor bearings seized: check and repair.
• Fan motor burnt-out; replace.
Note 1:
Do not release refrigerant to the atmosphere; use
refrigerant recovery equipment.
E N G L I S H
GB - 13