Daikin DAR09 - Checking Heater Elements; Checking Heater Limit Control(S); Checking Reversing Valve and Solenoid; Testing Defrost Control

66
SERVICING
WARNING
Disconnect ALL power before servicing.
1. Disconnect the heater lead in wires.
2. Using an ohmmeter, check heater connuity - should test
connuous. If not, replace.
NOTE: The posive temperature coecient crankcase heater is
a 40 wa 265 voltage heater. The cool resistance of the heater
will be approximately 1800 ohms. The resistance will become
greater as the temperature of the compressor shell increases.
S-21 CHECKING REVERSING VALVE AND SOLENOID
Occasionally the reversing valve may sck in the heang or cool-
ing posion or in the mid-posion.
When stuck in the mid-posion, part of the discharge gas from
the compressor is directed back to the sucon side, resulng in
excessively high sucon pressure. An increase in the sucon line
temperature through the reversing valve can also be measured.
Check operaon of the valve by starng the system and switch-
ing the operaon from COOLING to HEATING cycle.
If the valve fails to change its posion, test the voltage (24V)
at the valve coil terminals, while the system is on the COOLING
cycle.
All heat pumps and ComfortNetT™ heat pumps wired in legacy
- If no voltage is registered at the coil terminals, check the opera-
on of the thermostat and the connuity of the connecng
wiring from the “O” terminal of the thermostat to the unit.
S-24 TESTING DEFROST CONTROL
LEGACY MODELS:
To check the defrost control for proper sequencing, proceed as
follows: With power ON; unit not running.
1. Jumper defrost thermostat by placing a jumper wire across
the terminals “DFT” and “R”/”R-DFT” at defrost control
board.
2. Connect jumper across test pins on defrost control board.
3. Set thermostat to call for heang. System should go into
defrost within 21 seconds.
4. Immediately remove jumper from test pins.
5. Using VOM check for voltage across terminals “C & O”. Me-
ter should read 24 volts.
6. Using VOM check for voltage across fan terminals DF1 and
DF2 on the board. You should read line voltage (208-230
VAC) indicang the relay is open in the defrost mode.
7. Using VOM check for voltage across “W”/”W2” & “C” termi-
nals on the board. You should read 24 volts.
8. If not as above, replace control board.
9. Set thermostat to o posion and disconnect power before
removing any jumpers or wires.
NOTE: Remove jumper across defrost thermostat before return-
ing system to service.
S-25 TESTING DEFROST THERMOSTAT
1. Install a thermocouple type temperature test lead on the
tube adjacent to the defrost control. Insulate the lead point
of contact.
2. Check the temperature at which the control closes its
contacts by lowering the temperature of the control. Part #
0130M00009P which is used on 2 and 2.5 ton units should
close at 34°F ± 5°F. Part # 0130M00001P or B1370803 which
is used on 3 thru 5 ton units should close at 31°F ± 3°F.
3. Check the temperature at which the control closes its
contacts by lowering the temperature of the control. Part #
0130M00085, which is used onunits with 5 mm coils, should
close at 30°F ± 5°F.
4. Check the temperature at which the control opens its
contacts by raising the temperature of the control. Part
#0130M00009P which is used on 2 and 2.5 ton units should
open at 60°F ± 5°F. Part # 0130M00001P or B1370803 which
is used on 3 thru 5 ton units should open at 75°F ± 6°F.
5. Check the temperature at which the control opens its
contacts by raising the temperature of the control. Part #
0130M00085, which is used on units with 5 mm coils, should
open at 60°F ± 5°F.
6. If not as above, replace control.
S-50 CHECKING HEATER LIMIT CONTROL(S)
(OPTIONAL ELECTRIC HEATERS)
Each individual heater element is protected with an automat-
ic rest limit control connected in series with each element to
prevent overheang of components in case of low airow. This
limit control will open its circuit at approximately 150°F. to 160°F
and close at approximately 110°F.
WARNING
Disconnect ALL power before servicing.
1. Remove the wiring from the control terminals.
2. Using an ohmmeter test for connuity across the normally
closed contacts. No reading indicates the control is open
- replace if necessary. Make sure the limits are cool before
tesng.
IF FOUND OPEN - REPLACE - DO NOT WIRE AROUND.
S-52 CHECKING HEATER ELEMENTS
Oponal electric heaters may be added, in the quanes shown
in the spec sheet for each model unit, to provide electric resis-
tance heang. Under no condion shall more heaters than the
quanty shown be installed.