Start-Up Procedure And Checklist - Daikin DFG Series Installation Instructions Manual

SUPERHEAT = SUCTION LINE TEMP - SAT. SUCTION TEMP.
Superheat Adjustment
NOTE: Superheat adjustments should not be made until indoor
ambient conditions have stabilized. This could take up to 24 hours
depending on indoor temperature and humidity. Before check-
ing superheat, run the unit in cooling for 15-20 minutes or until
refrigerant pressures stabilize. Use the following guidelines and
methods to check unit operation and ensure that the refrigerant
charge is within limits.
For TXV systems, to adjust superheat, unscrew the cover from the
expansion valve, locate the adjustment screw, and turn it clock-
wise (in) to increase superheat or counterclockwise (out) to de-
crease superheat. It is recommended to make small adjustments
at a time, 1/8-1/4 turn increments. Replace adjustment cap. Wait
a minimum of 15 minutes between adjustments to allow time for
the TXV and pressures to stabilize.
Refrigerant Charge Check
NOTE: For optimal performance, follow charging instructions
below.
Units with Fixed Orifice Devices
All package units with fixed orifice devices are charged using the
superheat method at the compressor suction line. To increase su-
per heat, remove charge and to decrease super heat, add charge.
After superheat is adjusted, it is recommended to check unit sub-
cooling at the condenser coil liquid line. See Figure 14: DESIGN
SUPERHEAT AND SUBCOOLING table for targets on each model.
Units with Expansion valve (TXV)
Single Stage Cooling Application: Refer to the Design Superheat &
Subcooling table.
Two-Stage Cooling Application: Run unit on Low Stage cooling and
refer to Design Superheat & Subcooling table.
1. Purge gauge lines. Connect service gauge manifold to
access fittings. Run system at least 10 minutes to allow
pressure to stabilize.
2. Temporarily install thermometer on liquid (small) line
near liquid line access fitting with adequate contact and
insulate for best possible reading.
3. Check subcooling and superheat. System should have a
subcooling and superheat within the range listed on the
Design Superheat and Subcooling table.
a. If subcooling and superheat are low, adjust TXV su-
perheat, then check subcooling.
NOTE: To adjust superheat, turn the valve stem clock-
wise to increase and counterclockwise to decrease.
b. If subcooling is low and superheat is high, add charge
to raise subcooling then check superheat.
c. If subcooling and superheat are high, adjust TXV
valve superheat, then check subcooling.
d. If subcooling is high and superheat is low, adjust TXV
valve superheat and remove charge to lower the sub-
cooling.
NOTE: Do NOT adjust the charge based on suction
pressure unless there is a gross undercharge. If
an under charge is suspected recover the charge,
re-evacuate the system and recharge per data plate.
No adjustments should be made if suspecting a
charge issue.
5. Disconnect manifold set, installation is complete.
Design Superheat & Subcooling
Superheat
Model Circuit
± 2
DFG180 1
DFG180 2
DFG240 1
DFG240 2
DFG300 1
DFG300 2

START-UP PROCEDURE AND CHECKLIST

Begin with power turned on at all disconnects.
Air Conditioning Start-Up Procedure
1. Ensure the thermostat is set to OFF and Fan is set to Auto.
On units with DDC controls installed, use Test/ Balance
Menu to force the unit to Off Mode.
2. Inspect all registers and set them to the normal open
position.
3. Turn on the electrical supply at the disconnect.
4. Turn the fan switch to the "ON" position. The blower
should operate after a 7 second delay. On units with DDC
controls installed, use Test/Balance Menu to force the
unit to Vent Mode. This test bypasses internal delays.
5. Turn the fan switch to "Auto" position. The blower should
stop after a 65 second delay. On units with DDC controls
installed, use Test/Balance Menu to force the unit to Off
Mode. This test bypasses internal delays.
6. Set the thermostat to Cool mode and lower the cooling
until the unit is running both stage of cooling. The com-
pressors, blowers, and condenser fans should now be op-
erating. Allow the unit to run 10 minutes, make sure cool
air is being supplied by the unit. On units with DDC con-
trols installed, use Test/Balance Menu to force the unit to
High Cool Mode. This test bypasses internal delays.
7. Check that both compressors are operating correctly. The
scroll compressors in these units MUST operate in the
proper rotation. To ensure the compressors are operating
in the correct direction, check that the temperature of
the compressor discharge line increases when the com-
pressor turns on. If this does not occur and the compres-
sor is producing an exceptional amount of noise, this indi-
cates that there is a phasing issue. Perform the following
to correct:
20
Expan-
Subcooling
sion
F ± 1 F
0 0
Device
8 14 TXV
8 12 TXV
8 9 TXV
8 6 TXV
10 7 TXV
10 7 TXV
Outdoor
Ambient
(°F)
95
95
95
95
95
95