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9 Ductwork
This air handler is designed for a complete supply and return
ductwork system.
To ensure correct system performance, the ductwork is to be
sized to accommodate 350-450 CFM per ton of cooling with the
static pressure not to exceed 0.5" in w.c. Refer to ACCA Manual
D, Manual S and Manual RS for information on duct sizing and
application. Flame retardant ductwork is to be used and sealed to
the unit in a manner that will prevent leakage.
NOTE: A downflow application with electric heat must have an
L-shaped sheet metal supply duct without any outlets or registers
located directly below the heater.
9.1 Return Ductwork
DO NOT LOCATE THE RETURN DUCTWORK IN AN
AREA THAT CAN INTRODUCE TOXIC, OR OBJECTIONABLE
FUMES/ODORS INTO THE DUCTWORK. The return ductwork is
to be connected to the air handler bottom (upflow configuration).
10 Return Air Filters
Do not operate this product without all the ductwork attached.
Each installation must include a return air filter. This filtering may
be performed at the air handler using the factory filter rails or
externally such as a return air filter grille. When using the factory
filter rails, a nominal 16x20x1", 20x20x1" or 24x20x1" (actual
dimension must be less than 23-½"x20") filter can be installed on
a B, C and D cabinet respectively (the cabinet size is the seventh
letter of the model number).
11 Electric Heat
Refer to the installation manual provided with the electric heat kit
for the correct installation procedure. All electric heat must be
field installed. If installing this option, the ONLY heat kits that are
permitted to be used are the HKS series. Refer to the air handler
unit's Serial and Rating plate or the HKS specification sheets to
determine the heat kits compatible with a given air handler. No
other accessory heat kit besides the HKS series may be installed
in these air handlers.
The heating mode temperature rise is dependent upon the
system airflow, the supply voltage, and the heat kit size (kW)
selected. Use data provided in Tables 4, 5 and 6 to determine the
temperature rise (°F).
CAUTION
NOTE: For installations not indicated above the following formula
is to be used:
TR = (kW x 3412) x (Voltage Correction) / (1.08 x CFM)
Where: TR
=
kW
=
kW
=
3412
=
VC*
=
=
=
1.08
=
CFM
=
NOTE: The Temperature Rise Tables can also be used to
estimate the air handler airflow delivery. When using these tables
for this purpose set the room thermostat to maximum heat and
allow the system to reach steady state conditions. Insert two
thermometers, one in the return air and one in the supply air. The
temperature rise is the supply air temperature minus the return air
temperature. Using the temperature rise calculated, CFM can be
estimated from the TR formula above. See Technical Manual and/
or Service Manual for more information.
CFM
3
5
800
12
19
1000
9
15
1200
8
12
1400
7
11
1600
6
9
1800
5
8
2000
5
7
230/1/60 SUPPLY VOLTAGE - TEMP. RISE °F
CFM
3
5
800
11
18
1000
9
14
1200
7
12
1400
6
10
1600
6
9
1800
5
8
2000
4
7
220/1/60 SUPPLY VOLTAGE - TEMP. RISE °F
10
Temperature Rise
Heater Kit Actual kW
Heater Kit Actual kW
Btu per kW
.96 (230 Supply Volts)
.92 (220 Supply Volts)
.87 (208 Supply Volts)
Constant
Measured Airflow
*VC (Voltage Correction)
HEAT KIT NOMINAL kW
6
8
10
15
23
31
37
56
19
25
30
44
15
21
25
37
13
18
21
32
12
15
19
28
10
14
16
25
9
12
15
22
Table 3
HEAT KIT NOMINAL kW
6
8
10
15
22
30
35
54
18
24
28
42
15
20
24
35
13
17
20
30
11
15
18
27
10
13
16
24
9
12
14
21
Table 4
19/20
25
49
62
42
53
37
46
33
41
30
37
19/20
25
47
59
40
51
35
44
31
39
28
35
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