IM 830-6
42 www.DaikinApplied.com
Figure 76: Insulate Bulb and Suction Line Piping
Checking System Charge
The system charge should be checked under design conditions
[95°F outside air, 80°F/67°F (DB/WB) indoor air]. Refer to
condensing unit manufacturer's guidelines.
Before adjusting refrigerant charge, verify that the unit ventilator
is operating at normal design cfm. Nominal cfm is determined
with a dry coil, and cfm will be reduced during air conditioning
operation with a wet coil. Filters and coil must be clean and fan
speed set at high temperature to obtain subcooling.
Typical conditions - 95
°
F ambient, 75 psig suction, 285 psig head
pressure, 6-7
°
F superheat, 15
°
F subcooling.
NOTICE
Determining Subcooling
To determine correct subcooling:
1. Measure outdoor ambient. It must be between 65°F and 105°F.
2. Measure liquid line temperature 6 inches from the TXV inlet.
3. Measure liquid line pressure near the TXV.
4. Determine saturated liquid temperature from saturated
temperature pressure chart (
5. Subtract measured liquid line temperature from saturated
liquid temperature to obtain subcooling.
6. Adjust charge per condensing unit manufacturer
recommendation to obtain 15 - 16°F subcooling.
Figure 77: Typical Split System Evacuation/Charging Set-up
Liquid
Line Drier
Sight Glass
Suction Line Service Valve
Liquid Line Service Valve
Outdoor Fan
Compressor
Gauge Bar Hoses
Vacuum Pump
TXV
Indoor Fans
Charging
Cylinder
Indoor Coil
Outdoor Coil
Low Pressure
Gauge
Outdoor Condensing Unit
Unit Ventilator
High Pressure
Gauge
(By Others)
(By Others)
Pressure
Taps
(by others)
Table 36: Dimensions, DX Tubing inches (mm)
Unit Series
H07, V07 H10, V10 H13, V13 H15, V15 H20, V20
Suction Line O.D.
inches (mm)
3/4 (19)
3/4 (19)
7/8 (22)
7/8 (22)
7/8 (22)
Liquid Line O.D.
inches (mm)
1/4
(6.35)
1/4
(6.35)
3/8 (10)
3/8 (10)
3/8 (10)
Note:
piping dimensions are for systems with up to 30 ft. (9.14 m)
vertical separation and up to 100 ft (30.47 m) horizontal separation
from the outdoor condensing unit.
Figure 78: Typical Unit Ventilator/Condensing Unit Wiring Diagram
Hazardous Voltage!
Disconnect all electric power including remote disconnects before
servicing. Failure to disconnect power before servicing can cause
severe personal injury or death.
24V
Typical Condensing Unit
WARNING
!
To controls by others, to energize
condensing unit normally open contact
Typical Unit Ventilator Interface