Inspecting The Four-Way Valve; Inspecting The Sc Coil - Daikin GYEQ20AN Service Manual

Inspecting the Outdoor Unit

1.31 Inspecting the Four-way Valve

Four-way valve (normal heating)
1. Using a tester, check if the output voltage requirements specified above are met.
2. If the voltage is significantly different than specified above, stop the system using the
3. If the harnesses and connectors are OK, then check each component.
Inspect the four-way valve coil by measuring the resistance between its connectors.
Between connectors

1.32 Inspecting the SC Coil

While the system is running, inspect the SC coil contained in the receiver as follows:
1. Check if the number of pulses from EV4 is 5.
2. Calculate SH using the formula:
3. If SHS4 is approximately 0 with EV4 transmitting 5 pulses, chances are that EV4 or the SC
4. Measure the temperature at points T1, T2, and T3 indicated in the figure at right.
∗ This model is slightly different from other models, but there is no significant difference
197
Output voltage
Parts to inspect
onboard checker and wait for 5 minutes; then, with the power OFF, check the harness for
continuity and the junction connector for contact failure using a tester.
Inspecting the four-way valve coil
Measuring points
(Use the onboard checker's channel 10.)
SHS4 = intake air temperature 4 (CH28) - temperature equivalent temperature (CH55)
coil is broken.
If T1 is approximately equal to T2 and T3 is smaller than T2 minus 5 with EV4 transmitting 5
pulses, chances are that the SC coil is broken.
If T2 is smaller than T1 minus 5 with EV4 transmitting 5 pulses, chances are that EV4 is
broken.
regarding the measuring points.
Measuring points
Between power supply circuit
board's CN112-1 and -3
Measured value
1.2 kΩ
EV4
T2
T3
SiAUY361411EA
With actuator check
ON
CH12
200 V AC
EV1
T1
040431-00X00
Parts Inspection