DEFROST (40QAE Only) — The DFB energizes the RVS
(reversing valve solenoid), and the reversing valve switches
to the cooling position. The K1 relay on the DFB opens and
the outdoor fan stops. The W2 contact on the DFB is also
energized, which in turn energizes the defrost relay on the
fan coil relay board, turns off the electric heater and stops
the indoor fan.
The DFB logic checks the 10-minute defrost timer and
the DFT. If the DFT opens in less than 10 minutes, the DFB
switches the unit back to normal heating operation. If the
DFT remains closed, the DFB switches the unit back to heat-
ing operation after 10 minutes. When the DFB changes back
to heating mode, the RVR (reversing valve relay) is deen-
ergized and the reversing valve switches back to heating op-
eration. Both the outdoor and indoor fans come back on, and
if necessary, the electric heater also turns on.
SYSTEM SAFETIES — The system is equipped with the
following safety devices to protect system components:
A. Indoor coil freeze protection thermostat (40QAE unit cool-
ing cycle only) — If a coil temperature of 28 F or lower
is sensed, the compressor and outdoor fan will be shut
down until the coil temperature exceeds 28 F. The in-
door fan will continue to run.
B. Condensate float switch (40QA units equipped with ac-
cessory condensate pump, cooling cycle only) — If the
level of condensate in the drain pan rises too high, the
condensate float switch will turn off the compressor and
outdoor fan until the condensate level returns to normal.
The indoor fan will continue to run.
C. Outdoor Unit Safeties — These units are protected by
the following devices:
• high-pressure switch
• low-pressure switch (condensing units only)
• compressor internal overloads
• outdoor-fan motor internal overload
NOTE: Outdoor units with scroll compressors are also
protected by a high discharge gas temperature sensor and
a 2-minute timer to prevent possible reverse rotation of
the compressor.
Should any of these devices trip after the compressor is
energized, the Cycle-LOC™ protection device will lock out
the outdoor unit (turn it off) to prevent cycling on a safety
device.
SPECIAL OPERATION, HEATING — Outdoor cooling units
may be matched with heat pump ceiling-suspended fan coil
units to provide supplemental electric heat. All other opera-
tion is the same as a cooling-only system, except these units
have heating capability as follows:
When the room thermostat initiates a call for heating, the
electric heater is turned on. The indoor unit fan will start at
the same time if it was not already running.
When the heating requirement is satisfied, the room ther-
mostat will open, and the heater will turn off.
CLEANING AND MAINTENANCE
To avoid the possibility of electric shock, before per-
forming any cleaning and maintenance operations, al-
ways turn off power to the system by pressing the mode
button on the remote thermostat until the display shows
‘‘OFF,’’ and turning off the outdoor disconnect switch
located near the outdoor unit. If the indoor unit is on a
separate switch, be sure to turn this disconnect off as
well.
Do not wash filter in water over 120 F (to avoid shrink-
age). Do not expose filter to fire (to avoid fire damage).
Do not expose filter to direct sunlight. Clean filter more
frequently when air is extremely dirty.
Do not attempt to clean or service components in con-
trol box.
For proper system operation, perform the cleaning and main-
tenance operations in Table 8.
Lubrication —
The indoor-fan, automatic air sweep, and
the outdoor-fan motors are factory lubricated and require no
oiling.
To Remove and Clean or Replace Air Filters
(Fig. 23)
Operating your system with dirty air filters may damage
the indoor unit and, in addition, can cause reduced cool-
ing performance, intermittent system operation, frost
build-up on the indoor coil, and blown fuses. Inspect
and clean or replace the air filters monthly.
TO REMOVE AIR FILTERS — Remove filters by pulling
them straight out.
Fig. 23 — Cleaning Filters
15
Содержание 40QA
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