VRC Series IOM
11
IOM-M2-0316
Technical Support: (800) 789-8550
Part Number 478603
Charging Guidelines
Each circuit should be charged with the
compressor(s) at 100% and as much DX/condenser
load (highest ambient) as possible. Hot gas reheat
should be at 0% during initial charging. Let the
system run for at least 10 minutes between each
adjustment before rechecking. Refer to the following
table for adjustments.
Base Charge Measurement
Adjustment
High superheat and low subcooling = Undercharged
Add refrigerant to the system in small increments (0.5-1 lb.)
Low superheat and high subcooling = Overcharged
Remove refrigerant from the system in small increments (0.5-1 lb.)
Normal superheat and low subcooling = Undercharged
Add refrigerant to the system in small increments (0.5-1 lb.)
Normal superheat and high subcooling = Overcharged
Remove refrigerant from the system in small increments (0.5-1 lb.)
High superheat and normal subcooling = Over restricted
Loosen TXV adjustment screw by 1 or 2 turns
Low superheat and normal subcooling = Under restricted
Tighten TXV adjustment screw by 1 or 2 turns
High superheat and high subcooling = Over restricted
Loosen TXV adjustment screw by 1 or 2 turns
Low superheat and low subcooling = Under restricted
Tighten TXV adjustment screw by 1 or 2 turns
Recommended Line Sizes
All line lengths are equivalent line lengths and must
account for fitting pressure drop.
Casing
Tonnage
Circuit
Nominal
Capacity
(BTU/hr)
Discharge Line Size (inches)
Liquid Line
Size (inches)
0 – 40 ft *
40 – 100 ft
0 – 100 ft *
110
5
A
67,700
1/2
5/8
1/2
8
A
99,691
5/8
7/8
1/2
10
A
128,662
7/8
7/8
5/8
210
10
A
64,877
1/2
5/8
1/2
B
68,382
1/2
5/8
1/2
13
A
63,413
1/2
5/8
1/2
B
98,057
5/8
7/8
1/2
16
A
100,505
5/8
7/8
1/2
B
99,547
5/8
7/8
1/2
18
A
100,336
5/8
7/8
1/2
B
130,206
7/8
7/8
5/8
20
A
130,937
7/8
7/8
5/8
B
132,322
7/8
7/8
5/8
25
A
133,719
7/8
7/8
5/8
B
171,374
7/8
7/8
7/8
310
25
A
157,576
7/8
7/8
5/8
B
157,673
7/8
7/8
5/8
30
A
152,579
7/8
7/8
5/8
B
228,142
7/8
1 1/8
7/8
35
A
199,312
7/8
7/8
7/8
B
230,993
7/8
1 1/8
7/8
40
A
252,507
7/8
1 1/8
7/8
B
259,060
7/8
1 1/8
7/8
* Line size in this column = stub connection size on the VPR and VRC units.