Table of Contents
Advertisement
Figure 88 - Insulate Bulb and Suction Line Piping
Insulate Bulb, (Reacts
To Refrigerant Tempera-
ture and Not Ambient)
Insulate The Suction
Line Piping, (Minimum
Heat Pickup)
Checking System Charge
The system charge should be checked under design conditions [95ºF
outside air, 80ºF/67ºF (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.
NOTICE
Typical conditions - 95
F ambient, 75 psig suction, 285 psig head
º
pressure, 6-7
º
F superheat, 15
Determining Subcooling
To determine correct subcooling:
1. Measure outdoor ambient. It must be between 65ºF and 105ºF.
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 (table 22).
5. Subtract measured liquid line temperature from saturated liquid
temperature to obtain subcooling.
6. Adjust charge per condensing unit manufacturer recommendation
to obtain 15 - 16ºF subcooling.
Figure 90 - Typical Unit Ventilator/Condensing Unit Wiring Diagram
WARNING
Hazardous Voltage!
Disconnect all electric power including remote disconnects
before servicing. Failure to disconnect power before servicing
can cause severe personal injury or death.
IM 817-4
TXV (Thermal Expansion Valve)
Pressure Taps (Field Installed)
Supply (Liquid Line)
Pressure Taps
(Field Installed)
Return (Suction Line)
º
F subcooling.
Typical Unit Ventilator Interface
24V
Rec3
TDR or TB
3
2
T4
1
To controls by others, to energize condensing unit normally
open contact.
Figure 89 - Typical Split System Evacuation/Charging Setup
Compressor
Suction Line Service Valve
Low Pressure
Charging
Cylinder
(By Others)
Indoor Fans
Table 21 - Dimensions, DX Tubing inches (mm)
Models AVS, AVV,
AVB, AVR
S07
S10
S13
S15
S20
Note:
Table 21 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.
Head
Pressure
Controller
(Optional)
T
1
L
1
High
Pressure
Switch
Low
Pressure
Switch
Low Ambient
Temp. Switch
24V
TDR = Time Delay Relay
TB = Terminal Block
Outdoor Condensing Unit
Outdoor Coil
Outdoor Fan
Liquid Line Service Valve
High Pressure
Gauge
Gauge
Gauge Bar Hoses
Vacuum Pump
Indoor Coil
Unit Ventilator
Suction Line O.D.
3/4" (19mm)
3/4" (19mm)
7/8" (22mm)
7/8" (22mm)
7/8" (22mm)
Typical Condensing Unit
Capacitor
T
2
Compressor
Contactor
Compressor
L
2
Line Voltage
L
2
L
1
Factory Wired
Field Wired (By Others)
Liquid
Line
Drier
Sight Glass
(By Others)
TXV
Pressure
Taps
(by others)
Liquid Line O.D.
1/4" (6mm)
1/4" (6mm)
3/8" (10mm)
3/8" (10mm)
3/8" (10mm)
Fan
Motor
Page 31 of 60
Hide quick links:
Advertisement
Table of Contents
