9
Fixed Orifice
1. Temporarily install the thermometer on the suction (large) line
near the compressor. The thermometer should be located
within 4" (10.2 cm) to 6" (15.2 cm) of the compressor. Ensure
that the thermometer makes adequate contact and is
insulated.
NOTE: An optional method is to locate the thermometer at the
suction line service valve. Ensure that the thermometer makes
adequate contact and is insulated.
2. Refer to the System Superheat chart provided for proper
system superheat. Add charge to lower superheat or recover
charge to raise superheat.
Expansion Valve System
Single Speed Application
1. Temporarily install the thermometer on both the liquid (small)
and vapor (large) lines near the service valves. Ensure that
there is adequate contact. Insulate the sensors well for the
best possible reading. Use the liquid temperature to
determine subcooling and the vapor temperature to
determine superheat.
2. Check subcooling and superheat. Systems with TXV
application should have a subcooling of 5ºF to 9ºF and
superheat of 7ºF to 9 ºF.
■
If the subcooling and superheat are low, adjust TXV to 7ºF
to 9ºF superheat. Check subcooling.
NOTE: To adjust the superheat, turn the valve stem
clockwise to increase and counterclockwise to decrease.
■
If the subcooling is low and the superheat is high, add
charge to raise the subcooling to 5ºF to 9ºF. Check
superheat.
■
If subcooling and superheat are high, adjust TXV valve to
7ºF to 9ºF superheat. Check subcooling.
■
If subcooling is high and superheat is low, adjust TXV
valve to 7ºF to 9ºF superheat and remove charge to lower
the subcooling to 5ºF to 9ºF.
NOTE: Do not adjust the charge based on the suction
pressure unless there is a gross undercharge.
2-Stage Application
1. Temporarily install the thermometer on both the liquid (small)
and vapor (large) lines near the service valves. Ensure that
there is adequate contact. Insulate the sensors well for the
best possible reading. Use the liquid temperature to
determine subcooling and the vapor temperature to
determine superheat.
2. Check the subcooling and superheat. Systems with TXV
application should have a subcooling of 5ºF to 9ºF and
superheat of 7ºF to 9ºF.
■
If the subcooling and superheat are low, adjust TXV to 7ºF
to 9ºF superheat. Check subcooling.
NOTE: To adjust the superheat, turn the valve stem
clockwise to increase and counterclockwise to decrease.
■
If the subcooling is low and the superheat is high, add
charge to raise the subcooling to 5ºF to 9ºF. Check
superheat.
■
If subcooling and superheat are high, adjust TXV valve to
7ºF to 9ºF superheat. Check subcooling.
■
If subcooling is high and superheat is low, adjust TXV
valve to 7ºF to 9ºF superheat and remove charge to lower
the subcooling to 5ºF to 9ºF.
System Superheat
Outdoor Dry Bulb
Indoor Wet Bulb Temperature ºF
Temperature ºF
55
57
59
61
63
65
67
69
71
60
10
13
17
20
23
26
29
30
31
65
8
11
14
16
19
22
26
27
29
70
5
8
10
13
15
19
23
24
25
75
---
---
6
9
11
15
20
21
23
80
---
---
---
---
7
12
17
18
20
85
---
---
---
---
---
8
13
15
16
90
---
---
---
---
---
5
10
11
13
95
---
---
---
---
---
---
5
8
10
100
---
---
---
---
---
---
---
5
8
105
---
---
---
---
---
---
---
---
5
110
---
---
---
---
---
---
---
---
---
115
---
---
---
---
---
---
---
---
---
Goodman 30
To prevent personal injury, carefully connect and
disconnect manifold gauge hoses. Escaping liquid
refrigerant can cause burns. Do not vent refrigerant into
the atmosphere. Recover all refrigerant during system
repair and before final unit disposal.
WARNING