Low Voltage Connections; Expansion Valve Troubleshooting - Daikin AWSF18SU16 Series Installation Instructions Manual

12.1 Low Voltage Connections

Several combinations of low voltage schemes are possible,
depending on the presence of a heat kit and whether the
heat kit is single-stage or multi-stage, whether the outdoor
section is an air conditioner or heat pump, and whether
the outdoor section is single-stage or two stage. The
24V-control voltage connects the air handle to the room
thermostat and condenser. Low voltage wiring must be
copper conductors. A minimum of 18AWG must be used
for installations. Low voltage wiring must be connected
through the top of the cabinet or either side.
Speed
Model
AWSF18SU16** AA
AWST18SU14** AA
AWSF24SU16** AA
AWST24SU14** AA
AWSF30LU16** AA
AWST30LU14** AA
AWSF36LU16** AA
AWST36LU14** AA
NOTE:
1. Airflow data indicated is at 230V without air filter in
place.
2. Select a speed tap that provides a minimum 300 CFM
per outdoor ton. For satisfactory operation, external
static pressure must no exceed 0.3" WC (for electric
heater only).
CFM @ STATIC PRESSURE (IN W.C.)
Tap 0.1 0.2
T1 630 602
T2 630 602
T3 637 609
T4 630 602
T5 846 824
T1 630 602
T2 630 602
T3 784 763
T4 630 602
T5
846 823
T1 683 604
T2 900 856
T3 1079 1025
T4 944 897
T5 1168 1127
T1 1114 1072
T2 1114 1072
T3 1225 1191
T4 1287 1255
T5 1360 1329
Table 4

13 EXPANSION VALVE TROUBLESHOOTING

Before replacing an expansion valve, check the following
items:
1. Bulb location: Must be tightly secured to the suction
line upstream of the equalizer connection.
2. Insulation: Bulb must be properly insulated.
3. Equalizer: Must be connected to the 1/4" SAE
connection on the suction line.
4. Charge: Ensure the system is properly charged. There
MUST be a minimum of 10°F Sub-Cooled liquid at the
valve inlet.
0.3
If the system appears to be "starving" (low suction pressure
576
but insufficient cooling):
576
1. Check the Superheat (SH) at the evaporator outlet.
586
If SH is between 5°F - 12°F, the TXV is controlling
576
properly.
800
- Verify that there is proper airflow to the evaporator
576
(fan is operating and filter is unrestricted).
576
2. If SH is above 12°F, the setting of the TXV may be too
742
high.
576
- Adjust the SH by turning counter-clockwise to
800
decrease SH.
525
- Wait 20 minutes for the system to balance and adjust
803
again, as required.
989
- If adjusting the valve has no effect on the SH, the
848
valve may be stuck because of dirt or debris or it may
1083
have lost the Power Element charge.
1031
3. After properly reclaiming the refrigerant, remove the
1031
1152
TXV and check for dirt and debris. Clean, if possible, or
1219
replace the TXV and filter/drier.
1299
If the system appears to be "flooding" (compressor frosting
or moisture is condensing at the suction connection):
1. Check the SH at the evaporator outlet. If SH is
between 5°F - 12°F, the TXV is controlling properly.
2. If SH is less than 5°F, the SH adjustment may be too
low.
- Adjust the SH by turning the adjustment stem clock-
wise to increase the SH.
- Wait 20 minutes for the system to balance and ad-
just again as required.
- If adjusting the valve has no effect on the SH, the
valve may be stuck open because of dirt or debris or
moisture in the refrigerant.
3. After properly reclaiming the refrigerant, remove the
TXV and check for dirt and debris. Clean, if possible,
or replace the TXV and filter/drier. Add a moisture
indicator to allow checking of moisture if this is believed
to be a probable cause.
9