Maintenance And Troubleshooting - Carrier 42PQV...S Installation Manual

42PQV...S/38VBH...S

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 front panel complete with top cover by loosening
holding screws and lifting as shown.
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 front panel with cover and tighten the screws.
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.
• 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.
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 (outdoor or indoor, in case of heat pump
operation) obstructed; remove obstructions.
• Outdoor fan off; check cause and repair.
• Wrong indoor unit thermistors 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.
• Outdoor unit fan faulty; replace.
• 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 stopped; check cause and repair.
Discharge pressure too high:
• Outdoor coil dirty or obstructed; clean or remove obstructions.
• Condenser fan (outdoor or indoor, in case of heat pump
operation) faulty; replace.
• Indoor temperature selection too low in cooling or too high in
heating; check temperature selection.
• Air or other non-condensable gases in the circuit; drain
refrigerant (see note 1), evacuate and recharge.
Discharge pressure too low:
• Indoor temperature selection too high in cooling or too low in
heating; check temperature selection.
• Outdoor coil dirty or obstructed; clean or remove obstructions.
• Indoor unit air filter dirty; clean filter.
Suction pressure too high:
• Indoor temperature selection too low in cooling or too high in
heating; check temperature selection.
• Reversing valve (on heat pump models) faulty or internal leak;
replace.
Suction pressure too low:
• Indoor temperature selection too high in cooling or too low in
heating; check temperature selection.
• Evaporator coil (indoor or outdoor, in case of heat pump
models),covered with ice; see the following points.
• Air circulation on the evaporator unit (indoor or outdoor, in case
of heat pump models) not sufficient; check for the cause and
repair.
• Expansion device or suction line clogged: check and repair.
• Outdoor fan does not stop during defrost periods (when heating
with heat pump models); check electrical parts.
Outdoor fan cycling due to its overtemperature protection:
• Electrical connection loose; check connections.
• Fan motor burnt out; replace.
• Fan bearing seized; check and repair.
• Expansion device clogged or covered with ice; drain refrigerant
(see note 1), evacuate and recharge.
Note 1:
Do not release refrigerant to the atmosphere; use
refrigerant recovery equipment.
E N G L I S H
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