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The Ductless Split System of Choice
27
TROUBLESHOOTING PROCEDURE
Continued
Frequently Asked Questions
Q:
The system has just been installed using an EMI indoor
unit and a non-EMI condenser. There is no display and
the unit will not operate.
A: As of 12/01/04 EMI air handlers will be manufactured
with a low Volt transformer installed. At the same
time, EMI outdoor condensers will be manufactures
without a low Volt transformer.
When connecting
an EMI evaporator to a non-EMI condenser, check to
ensure that there is a 24V control transformer in either
in the indoor unit or outdoor unit. Only one transformer is
required. If a transformer is not present then one should
be added to the indoor unit. If both the indoor unit and
outdoor unit contain a transformer, one must be removed
from the system.
Q:
The condenser will not start although the indoor unit
appears normal. What should I do?
A:
At the indoor unit, make sure that the control is in cooling
and the setpoint temperature is below room temperature.
Next, using a volt meter, check for 24V across the yellow
(Y) and brown (C) wires. If 24V is present then check
for wiring breaks or improper connections between the
indoor and outdoor units.
A:
Some EMI condensers are equipped with a manual reset
high-pressure switch. It is located on the high side of the
system usually on the discharge line of the compressor.
To reset, simply push the red button in. If the switch was
tripped there will be a “click” when it resets.
A:
If the unit is equipped with a condensate pump check to
see if the safety float has been tripped. This can be done
by first disconnecting both ends of the float switch. Then
with an Ohmmeter, check for continuity across the switch.
If the switch is open then the pump is not clearing or the
switch may be bad.
Q:
The display on the indoor unit is blank. What should I do?
A:
Check the power supply (see “Power supply check”
Section). If the unit still fails to turn on via the
On/off
button then inspect the control box for any apparent wires
that may have come loose during shipping. Also inspect
the circuit boards for burnt components. If no obvious
problem can be found then replace all circuit boards
including the unit keypad. Do not attempt to trouble shoot
the individual circuit boards.
Q:
The display tends to flicker at times. Is this normal?
A:
A small amount of flickering of the display is normal.
Depending on the room lighting, flickering may be more
noticeable at some times than others.
Q:
How long will the fan run?
A:
While the unit is in cooling or heating and auto fan
mode is selected, Fan speed will be determined by the
microprocessor and speed adjustment will be made
according to room and setpoint temperatures. The
fan will switch to
High
speed when room temperature
deviates by more than two degrees from setpoint. The
fan will switch to
Low
speed if the deviation is one
degree. When the room temperature reaches setpoint
temperature the heat/cool call is dropped. The fan will
then stay on for an additional 60 sec. to purge unit of any
residual energy. If
High
or
Low
is selected then the fan
will operate continuous regardless of set point or room
temperatures.
Q:
What causes my indoor unit to freeze-up?
A:
Evaporator freeze up is usually the symptom of another
problem. Units with infrared compatible, unit mounted
controls are equipped with freeze protection to prevent
freeze up from occurring. If freeze up does occur then
check the following.
•
Check that the freeze sensor located in the lowest
part of the coil. Generally this is where freeze up
will begin.
• Check that the freeze sensor inserted fully and snug
in the coil fin. If not another location may need to be
selected. Be careful not to insert the sensor directly
into the coil tube rather insert the sensor between two
tubes.
• Check the indoor air filter. It should be clean and free
of dirt. A dirty filter will reduce airflow and efficiency.
Also check that the coil is clean. If the coil is dirty then
it should be cleaned using an appropriate coil cleaner
or mild detergent.
• Is the equipment being operated in cooling mode
when outdoor temperatures are below 65°F? If it is,
then the condenser should be fitted with low ambient
control so that the proper system pressures are
maintained.
• Does the system have the proper refrigerant charge?
A system low on refrigerant can cause evaporator
freeze-up. To check system charge you will need to
contact a qualified refrigeration service technician.
Refrigerant charge information can be found in IOM
for the outdoor condensing unit.
