Troubleshooting - Lennox MS8 Manual

Troubleshooting

ELECTRICAL SHOCK HAZARD! Never attempt to repair the indoor or outdoor unit yourself. System repairs must be
performed by a licensed, professional technician, or equivalent.
If any of the following conditions exist, immediately turn the system (indoor and outdoor units) off at the unit disconnect
switch and call a licensed professional technician, or equivalent, for repairs
D
There is a very loud sound during unit operation.
D
There is a terrible odor coming from the indoor unit during operation.
D
Water is leaking into the room.
D
The circuit breaker trips frequently.
D
Water or some other liquid has been splashed into the indoor unit.
If none of the above conditions exist, check the following items before calling for repairs. This can save you both time
and money.
Unit does not operate immediately when restarted.
A whoosh or gurgling noise can be heard at the indoor unit.
Mist is coming out of the indoor unit during cooling operation.
A creaking or popping noise can be heard when the unit starts or stops.
Unit is not operating.
System is not cooling (or heating) efficiently.
Wireless remote is not working.
Water is leaking from indoor unit.
Water is leaking from condensate line at Water is leaking from conden­
sate line at indoor unit.indoor unit.
Water is leaking from the outdoor unit.
Clicking noise heard inside.
Indoor fan is not working.
Problem
WARNING!
Unit control initiates a 3-minute delay at the end of each cycle to protect
the compressor from damage.
Sometimes, the refrigerant can be heard in the indoor coil when the
outdoor unit starts or stops operation. This is not a malfunction.
This sometimes happens when the indoor temperature and humidity are
very high and the air is being cooled quickly. The mist will disappear as
the indoor temperature and humidity are lowered.
The plastic components of the indoor units sometimes expand and con­
tract when they are heated and cooled.
Are the TIMER ON and TIMER OFF features being used incorrectly?
Is power disconnected or has circuit breaker tripped.
Is power shut down?
Is temperature setting correct?
Are either the air inlet or air outlet blocked on the outdoor or indoor unit?
Is filter dirty?
Is fan at low speed?
Are windows and doors properly shut?
Is remote in direct line of sight with indoor unit infrared receiver? Has
the remote been damaged?
Remove remote control batteries for 30 seconds, then reinsert them.
Replace batteries, if necessary.
Indoor humidity level is very high and water is being blown from indoor
coil. This will stop as humidity level is reduced.
Check condensate line outside to make sure it is not obstructed.
Check condensate line to make sure it has not been disconnected from
indoor unit.
During operation in high-humidity areas, condensate will form on cold
outdoor refrigerant pipes.
When heat pump is operating in defrost mode, ice will thaw from around
outdoor coil and water will flow from the unit.
Sometimes, the sound of the outdoor unit fan or compressor relay can
be transmitted in a way that makes it seem to be coming from the indoor
unit.
Heat pump units -- In HEAT mode, a timed delay keeps indoor fan off
for two minutes to prevent unheated air from being circulated by the
indoor fan.
Heat pump units -- In HEAT mode, cold outdoor temperatures and high
humidity cause frost to accumulate on the outdoor unit. When this hap­
pens, the unit will enter a defrost cycle. The indoor fan is off during the 3
- 12 minute cycle.
In DEHUMIDIFICATION mode, indoor fan operation may be stopped to
avoid delivery of moist air to the room. Do not adjust temperature set­
ting.
11
Possible Cause