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2 – RFCIII Systems
The system should not be charged at ambients below
60 _F (15_C). If charging below 60 _F (15_C) is required,
the recommended method of charging is to weigh the
refrigerant into the unit according to the total amount
shown on the unit nameplate. For line sets varying from
20 feet , refer to table 8 for refrigerant charge adjustment.
If ambient temperature is above 60 _F (15_C) use the
subcoooling method outlined below.
SUBCOOLING METHOD (RFCIII SYSTEMS)
(Ambient Temperature Above 60_F [16_C] )
1 – Connect gauge manifold. Connect an upright
R–22 drum to center port of gauge manifold.
2 – Operate indoor and outdoor units in cooling
mode. Allow outdoor unit to run until system
pressures stabilize.
3 – Make sure thermometer well is filled with
mineral
oil
before
temperature.
4 – Read liquid line pressure and convert to
condensing temperature using temperature/
pressure conversion chart.
Condensing temperature (read from gauges)
should be a few degrees warmer than the
liquid line temperature.
TABLE 12
SUBCOOLING METHOD––RFCIII Systems*
Indoor
Outdoor
Unit
Unit
HP23–141
CB/CBH19–21
HP23–211
CB/CBH19–21
HP23–261
CB/CBH19–26
HP23–311
CB/CBH19–31
HP23–410
CB/CBH19–41
HP23–410 (CAN) CB/CBH19–41
HP23–460
CB/CBH19–41
HP23–510
CB19–51
*Approved matchups only
5 – Place thermometer in well and read liquid line
temperature. Table 12 shows how much
warmer the condensing temperature should be.
checking
liquid
line
Condensing Temp F Warmer
Than Liquid Line At Various
Ambients
65_F 75_F 85_F 95_F 105_F 115_F
5
5
4
1
0
0
13
13
13
12
6
4
12
12
11
9
7
5
12
12
10
8
6
4
17
15
14
11
8
5
18
16
15
12
9
6
11
10
7
6
4
2
11
10
8
7
5
2
Add refrigerant to make the liquid line
temperature cooler.
Recover refrigerant to make the liquid line
temperature warmer.
6 – When unit is properly charged liquid line
pressures should approximate table 11.
E – Oil Charge
Refer to table 5 on page 6.
V – MAINTENANCE
At the beginning of each heating or cooling season, the
system should be cleaned as follows:
A – Outdoor Unit
1 – Clean and inspect outdoor coil. (Coil may be
flushed with a water hose).
2 – Visually inspect all connecting lines, joints and
coils for evidence of oil leaks.
IMPORTANT
If insufficient heating or cooling occurs, the unit
should be gauged and refrigerant charge checked.
B – Indoor Coil
1 – Clean coil if necessary.
2 – Check connecting lines and coil for evidence of
oil leaks.
3 – Check condensate line and clean if necessary.
C – Indoor Unit
1 – Clean or change filters.
2 – Adjust blower cooling speed. Static pressure
drop over coil should be checked to determine
correct
blower
Engineering Handbook.
3 – Belt Drive Blowers - Check condition and
tension.
4 – Check all wiring for loose connections.
5 – Check for correct voltage at unit.
6 – Check amp–draw on blower motor.
Unit nameplate_________Actual_________.
Page 15
CFM.
Refer
to
Lennox
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