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13
Multi-zone Heat Pump Condensing Units
S2HA & T2HA REFRIGERANT PIPING INSTALLATION SECTION
The use of the superheat method is highly
recommended for field charging or checking
the existing refrigerant charge in a system.
Because each installation is different in terms
of indoor air flow, refrigerant line length, etc..,
the factory charge may not be correct for
every application. To assure the best perfor
-
mance from the air-conditioner, the refrigerant
charge should be checked and adjusted, if
need be, on each installation.
For proper superheat readings, a standard
low-side refrigerant gauge and an accurate
thermometer are needed. A mercury or
stem-type thermometer is not adequate
for suction-line temperatures. We recom
-
mend electric thermocouple thermometers
(available at most refrigeration wholesal
-
ers); however an accurate remote-bulb
thermometer can be used. When mea
-
suring the line temperature, be sure the
thermometer is well insulated to assure
accurate measurements. The chart below
gives superheat values at various outdoor
temperatures. Allow at least 5 minutes run-
ning time between charge adjustments for
the unit to stabilize.
The S & T series (S2HA, T2HA, T3HA &
T4HA) has manifold access points on each
of the service valves for the high and low
pressures in cooling mode. There is an
additional “common suction” access point
above each service valve set to provide low
pressure access in the heating mode as both
service valves are at high side pressure.
FIELD CHARGING
S2HA & T2HA REFRIGERANT CHARGE TABLE
Circuit
Capacity Btuh
Evaporator
Pairing
Line
Chg/ft
Line
Length
Line
Adjust
Factory
Charge
Total
Charge
9000
WLHA09
CAHB12
0.25 oz
10 ft
25 ft
50 ft
3 oz
6 oz
13 oz
42
45 oz
48 oz
55 oz
12000
WLHA12
CAHB12
0.25 oz
10 ft
25 ft
50 ft
3 oz
6 oz
13 oz
46
49 oz
52 oz
59 oz
18000
WLHA24
CAHB24
0.56 oz
10 ft
25 ft
50 ft **
6 oz
14 oz
28 oz **
80
86 oz
94 oz
108 oz
24000
WLHA24
CAHB24
0.56 oz
10 ft
25 ft
50 ft
6 oz
14 oz
28 oz
80
86 oz
94 oz
108 oz
** Any 18,000 Btuh circuit with more than 57 feet of tubing (> 112 oz of total refrigerant charge) requires a 25W
wrap around Crank Case Heater.
IMPORTANT NOTES:
1. To find the charge adjustment and system charge for any evaporator and
tubing length:
Line Adjustment = (Line Chg/Ft) x Line Length
System Total = Factory Charge + Line Adjustment
2. Round to the nearest ounce and allow for gauges and hoses.
3. Use R22 refrigerant.