Condensing Unit & Heat Pump R410A Service Manual

114
SERVICING
Other components such as a Heang/Cooling Thermostat and
Outdoor Thermostats are available to complete the installaon.
The system CFM can be determined by measuring the stac
pressure external to the unit. The installaon manual supplied
with the blower coil, or the blower performance table in the
service manual, shows the CFM for the stac measured.
Alternately, the system CFM can be determined by operang
the electric heaters and indoor blower WITHOUT having the
compressor in operaon. Measure the temperature rise as close
to the blower inlet and outlet as possible.
If other than a 240V power supply is used, refer to the BTUH
CAPACITY CORRECTION FACTOR chart below.
BTUH CAPACITY CORRECTION FACTOR
SUPPLY VOLTAGE 250 230 220 208
MULTIPLICATION FACTOR 1.08 .92 .84 .75
EXAMPLE: Five (5) heaters provide 24.0 KW at the rated
240V. Our actual measured voltage is 220V, and our measured
temperature rise is 42°F. Find the actual CFM:
Answer: 24.0KW, 42°F Rise, 240 V = 1800 CFM from the
TEMPERATURE RISE chart on the right.
Heang output at 220 V = 24.0KW x 3.413 x .84 = 68.8 MBH.
Actual CFM = 1800 x .84 Corr. Factor = 1400 CFM.
NOTE: The temperature rise table is for sea level installaons.
The temperature rise at a parcular KW and CFM will be
greater at high altudes, while the external stac pressure at a
parcular CFM will be less.
CFM
3.0
kW
4.8
kW
7.2
kW
9.6
kW
14.4
kW
19.2
kW
24.0
kW
28.8
kW
600 16 25 38 51 - - - -
700 14 22 33 43 - - - -
800 12 19 29 38 57 - - -
900 11 17 26 34 51 - - -
1000 10 15 23 30 46 - - -
1100 9 14 21 27 41 55 - -
1200 8 13 19 25 38 50 - -
1300 7 12 18 23 35 46 - -
1400 7 11 16 22 32 43 54 65
1500 6 10 15 20 30 40 50 60
1600 6 9 14 19 28 38 47 57
1700 6 9 14 18 27 36 44 53
1800 5 8 13 17 25 34 42 50
1900 5 8 12 16 24 32 40 48
2000 5 8 12 15 23 30 38 45
2100 5 7 11 14 22 29 36 43
2200 4 7 11 14 21 27 34 41
2300 4 7 10 13 20 26 33 39
TEMPERATURE RISE (°F) @ 240V
HTR
KW
3.0
KW
4.7
KW
6.0
KW
7.0
KW
9.5
KW
14.2
KW
19.5
KW
21.0
KW
BTUH 10200 16200 20400 23800 32400 48600 66500 71600
ELECTRIC HEATER CAPACITY BTUH
FORMULAS:
Heang Output = KW x 3413 x Corr. Factor
Actual CFM = CFM (from table) x Corr. Factor
BTUH = KW x 3413
BTUH = CFM x 1.08 x Temperature Rise (T)
CFM = KW x 3413
1.08 x T
T = BTUH
CFM x 1.08
S-61A CHECKING HEATER LIMIT CONTROL(S)
Each individual heater element is protected with a limit control
device connected in series with each element to prevent
overheang of components in case of low airow. This limit
control will open its circuit at approximately 150°F.