Components Testing - Friedrich KUHL R-410A Service Manual

COMPONENTS TESTING

HEATING ELEMENT
All heat pumps and electric heat models are equipped
with a heating element with the exception of model
YS10M10. The other "YS" and "ES" models are
equipped with a 3.3 KW element. The "YM" and "EM"
models are equipped with a 4.0 KW element. The
"YL" and "EL" models are equipped with a 5.2 KW
element.
The heating element contains a fuse link and a heater
limit switch. The fuse link is in series with the power
supply and will open and interrupt the power when the
temperature reaches 199°F or a short circuit occurs in
the heating element. Once the fuse link separates, a
new fuse link must be installed.
NOTE: Always replace
replacement.
The heater element has a high limit control. This
control is a bimetal thermostat mounted in the top of
the heating element.
Should the fan motor fail or fi lter become clogged,
the high limit control will open and interrupt power to
the heater before reaching an unsafe temperature
condition.
The control is designed to open at 110°F ±6°F. Test
continuity below 110°F and for open above 110°F.
HEATING ELEMENT (Heat Pump Models)
The heating element for the "Y" model is energized
by an outdoor thermistor via the electronic control
board. The outdoor defrost thermistor is adjusted at
a predetermined temperature to bring on the heating
element and turn off the compressor. The room
Heating Element
Sample
with the exact
TESTING THE HEATING ELEMENT
WARNING
ELECTRIC SHOCK HAZARD
Disconnect power to the unit before
servicing. Failure to follow this warning
could result in serious injury or death.
Testing of the elements can be made with an ohmmeter
across the terminals after the connecting wires
have been removed. A cold resistance reading of
approximately 14.5 ohms for the 3.3 KW heater, 11.9
ohms for the 4.0 KW heater and 9.15 ohms for the 5.2
KW heater should be registered.
DRAIN PAN VALVE
During the cooling mode of operation, condensate
which collects in the drain pan is picked up by the con-
denser fan blade and sprayed onto the condenser coil.
This assists in cooling the refrigerant plus evaporating
the water.
During the heating mode of operation, it is necessary
that water be removed to prevent it from freezing during
cold outside temperatures. This could cause the con-
denser fan blade to freeze in the accumulated water
and prevent it from turning.
To provide a means of draining this water, a bellows
type drain valve is installed over a drain opening in the
base pan.
This valve is temperature sensitive and will open when
the outside temperature reaches 40°F. The valve will
close gradually as the temperature rises above 40°F to
fully close at 60°F.
Bellows Assembly
Drain Pan Valve
35