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23
CAC Cassette Evaporator
TROUBLESHOOTING PROCEDURE
Continued
Frequently Asked Questions
Q:
The system has just been installed using
an EMI indoor unit and a non-EMI con-
denser and the unit will not operate.
A:
The CAC air handlers is manufactured
with a low Volt transformer installed.
EMI outdoor condensers are manufac-
tured 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 both the indoor unit and outdoor unit
contain a transformer, one must be re-
mover from the system.
Q:
The condenser will not start although
the indoor unit appears normal. What
should I do?
A:
At the indoor thermostat, 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 improp-
er 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, sim-
ply push the red button in. If the switch
was tripped there will be a “click” when
it resets.
A:
CAC air handlers are equipped with an
internal condensate pump with a high
level safety switch. If the condensate
reaches a critical level or if power is
lost to the indoor unit, the safety cir-
cuit will open and low Volt power to the
condenser (terminal “Y1”) will be re-
moved. The condensate pump should
be checked for obstruction. The con-
densate pump assembly can be re-
moved through the side access panel.
After removal, inspect the drain pan
to determine if the condensate is not
being removed properly from the unit.
Inspect all drain lines to ensure there
is no blockage preventing condensate
removal.
Q:
How long will the fan run?
A:
While the unit is in cooling or heating
and auto fan mode is selected, the
fan will cycle with the call for cooling
or heating. When the room tempera-
ture 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.
Q:
What causes my indoor unit to freeze-up?
A:
Evaporator freeze up is usually the
symptom of another problem. CAC air
handler units 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 inserted
fully and snug in the coil fin. If not an-
other location may need to be select-
ed. 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 us-
ing an appropriate coil cleaner or mild
detergent.
Summary of Contents for CAC
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