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Thermistors
Thermistors provide temperature feedback to the
main board to maintain proper room temperature
and operating conditions of the sealed system.
On heat pump models (AZ65), thermistors also
provide outdoor air temperature and outdoor coil
temperature in order for the main board to operate
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A separate transformer provides low voltage for the
main board and also the wall thermostat. A built-in
resettable fuse circuit is enclosed in the transformer;
this prevents the transformer from becoming
defective if the wires are shorted.
RJ-45
A RJ-45 connector is mounted to the printed
circuit side of the main control board to provide a
way to easily update software or to hook up other
monitoring devices. It is accessible by removing the
front cover of the Zoneline.
Fan Motors
Both the indoor and outdoor fan motors are DC
motors driven by the main board, and provide
speed feedback to the main board for proper speed
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Heater
All models of the new Zoneline have one three-bank
heater assembly. They have two thermal switches
to protect the circuit; one is a cycling thermal switch
and the other is a "one-shot" thermal switch.
Sealed System
As with any refrigeration system, Zonelines have an
indoor coil, compressor and refrigerant metering
device (capillary tubes). A drier is part of the sealed
system now included from the factory.
Additionally, on heat pump models (AZ65), a
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a check valve to balance the system are parts of the
sealed system.
A "tank" is part of some sealed systems in the
Zoneline models. The tank allows for expansion of
the refrigerant, where required.
NOTE: A new drier MUST be installed anytime a
sealed system is repaired.
A thermal fuse in line with the compressor L2 circuit,
to protect the housing area. The compressor circuit
is still protected with an overload in the compressor
cover.
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265 volt models must be wired directly to the house
supply. See the
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section in this
service guide for sub-base assembly parts.
In addition, the 20 and 30 amp cords will have a
separate heater enabling jumper that plugs into the
main control board which limits the heater wattage
according to house supply limitations. If this jumper
is not connected the heater circuit will be limited to
15 amp operation.
ICR Pump
On some Zoneline models, an internal Condensate
Pump is mounted into the outer base pan. As with
previous ICR models, this pump is designed to pump
condensate water, which accumulates from the
outdoor coil when in heat pump mode, up to the
top of the indoor coil and allows the water to trickle
down the coil to evaporate. This process cuts down
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Zoneline and adds moisture to the indoor air.
Make Up Air Module
Some models will have a separate module that
conditions air from the outside before it enters the
room through the duct door. This module consists
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enclosed into one package. This is not a serviceable
part, and is replaced as a complete module
assembly. This is a new requirement of building
codes in some areas.
Reversing Valve Solenoid
See Sealed System Heat Pump section in this
service guide.