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Heater Assembly
The heater assembly consists of three 230/208 VAC
or 265 VAC resistance heating coils, a L248 one-shot
protector (fuse), and a L167-30 auto reset protector.
The one-shot thermal protector is used as a backup
in case the auto reset thermal protector fails (stuck
closed). The assembly is located inside the air
plenum behind the indoor coil. The heaters and
protectors are removed as an assembly.
To access heater assembly, see Indoor AC Fan Motor.
Heater Test 2800 Series
With power disconnected and the heater wire
harness unplugged check for resistance of each
individual heater:
RY103 black wire to harness black wire
(1 KW heater) = approximately 60 Ω
RY103 black wire to harness red wire
(1.55 KW heater) = approximately 37 Ω
RY 103 black wire to harness white wire
(2.45 KW heater) = approximately 24 Ω
Caution: Do not touch or press the round face of
the one shot protector. The round portion of the
one shot protector is curved out (convex). If the
round face is pushed in (concave), the protector
contacts open and will not reset. Pushing in on the
round face destroys the protector.
Note: Open circuit indicates either open heaters
and/or protectors. If all heaters measure open,
check for open protectors.
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To check the heater protector circuit on the 3800
series, check between the RY103 (black-fabric) to the
one- or 2-pin black-fabric connector located in the
wire bundle. The value should be less than 1 Ω.
Heater Test 3800 Series
With power disconnected and the heater wire
harness unplugged check for resistance of each
individual heater:
RY109 Brown wire to the 3-wire harness black
wire = 51.5 Ω (1 kw)
RY102 Orange wire to the 3-wire harness red
wire = 32.8 Ω (1.55 kw)
RY102 Orange wire to the 3-wire harness white
wire = 20.8 Ω (2.45 kw)
With unit connected to the power supply and in
heat mode, check for heater voltage (230/208 VAC)
from RY103 black wire to RY102 brown wire (2800)
or gray wire (3800). For 3800 models, place #1
dip switch up (I2R) and set thermostat to warmest
setting.
Heat Pump models will utilize electric resistance
heat upon initial heat mode startup or when a
power outage has occurred with the unit in heat
mode. The electric heaters will be energized until
the room temperature reaches the thermostat
setting. Once the thermostat temperature setting
is attained, the unit will cycle off and automatically
switch over to heat pump operation.
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