Lennox MCFA Series User Manual page 6

• On an initial call for cooling, the operation/run light is lit to signal normal operation. There will be a delay after a cooling
demand is introduced be fore unit operation begins. This delay protects the unit compressor and is normal.
• When a heating demand is initiated, the opera tion light is lit to signal normal operation. The PRE-DEF indicator may
be lit as well. The indoor unit fan will not operate until the indoor coil reaches a pre-set temperature. This prevents the
delivery of cold air into the space and is nor mal.
Indoor fan is on; compressor is off
In certain normal operating modes, the indoor fan is on when the compressor is not operating.
• The system turns the compressor off and leaves the indoor fan on when the indoor coil falls to a preset temperature.
This is normal operation and will prevent the indoor coil from freezing.
• When the indoor fan is set for continuous opera tion, the fan continues to run when the temperat ure setting is reached
and the compressor is de-energized.
White mist comes out of the indoor unit
• During cooling operation, if the indoor relative humidity is very high and the indoor unit dis charge air louvers are very
dirty, the indoor coil may freeze and a white mist (frozen vapor) may appear to come from the indoor unit. In this case,
though the unit is not in need of repair, it does need to be cleaned by a licensed pro fessional HVAC technician
(or equivalent).
• During heating operation when the operation mode switches from defrost to heating, mois ture generated by the
defrost process becomes steam and may be seen as it is blown out of the indoor unit.
Sounds can be heard near the indoor unit
During certain parts of the heating or cooling pro cess, low swishing or groaning sounds may be heard near the unit as the
system pressures equal ize. This is a normal occurrence.
The table below lists possible causes and solutions to some of the most common problems. Please review this information
before calling for service.
Symptom
Unit does not start.
Indoor fan is operating; however, air is
not cool.
Unit cycles on and off frequently.
Unit not cooling properly.
Table 1. Troubleshooting
Possible Cause
• Power failure
• Power to unit is OFF or disconnected
• Circuit breaker may be tripped or fuse may be
blown
• Wireless remote control batteries may have
lost their charge or unit controller may have
malfunctioned
• Temperature not properly set at con trol
• Compressor may be kept off by delay
• Refrigerant charge is incorrect
• Air in refrigerant circuit
• Compressor malfunction
• Improper voltage
• System refrigerant circuit is blocked
• Indoor and/or outdoor coil are dirty
• Air filter is dirty
• Air flow around indoor and/or outdoor unit is
obstructed
• Doors and/or windows are open
• Direct sunlight is affecting indoor tem perature
• Heat source inside is placing a large burden on
the system
• Suction pressure is low due to possible refrig-
erant leak
Possible Solution
• Wait for power to be restored
• Turn on or reconnect power to the unit
• Reset circuit breaker or replace fuse
• Replace AAA size batteries in wireless remote
control. Check controller for proper function
• Check temperature setting at control
• Wait for delay to expire
• Check for refrigerant leaks and prop erly charge
system
• Evacuate and properly charge system
• Check compressor and replace, if ne cessary
• Check with utility company to provide proper
voltage
• Clear blockage
• Clean indoor and/or outdoor coil
• Clean or replace air filter
• Remove obstructions
• Close doors and windows
• Use curtains or blinds to block direct sunlight.
• Reduce burden of heat source
• Check for refrigerant leaks and prop erly charge
system
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