Install Instructions

10
10 Return Air Filters
Each inst allation must include a ret urn air filt er. This filt ering may be performed at the air handler using the factory filter rails or
ext ernally such as a return air filter grille. When using the factory filt er rails, a nominal 16x20x1” , 20x20x1” or 24x20x1” (actual
dimension must be less than 23-½” x20” ) filt er can be inst alled on a B, C and D cabinet respectively (t he cabinet size is the sevent h let t er
of the model number).
11 Electric Heat
Refer to the inst allation manual provided with the electric heat kit for the correct installation procedure. All electric heat must be field
inst alled. If inst alling this option, the ONLY heat kit s t hat are permitted to be used are the HKS series. Refer to the air handler unit’s
Serial and Rating plate or the HKS specification sheet s to det ermine the heat kits compat ible wit h a given air handler. No other
accessory heat kit besides the HKS series may be inst alled in these air handlers.
The heat ing mode temperat ure rise is dependent upon the system airflow, the supply volt age, and the heat kit size (kW) selected. Use
dat a provided in Tables 2, 3 and 4 to det ermine the temperat ure rise (°F).
NOTE: For inst allations not indicated above the following formula is t o be used:
TR = (kW x 3412) x (Volt age Correction) / (1.08XCFM )
Where: TR = Temperature Rise
kW = Heat er Kit Actual kW
3412 = Btu per kW
VC* = .96 (230 Supply Volts)
= .92 (220 Supply Volts)
= .87 (208 Supply Volts)
1.08 = Constant
CFM = M easured Airflow
* VC (Voltage Correction)
NOTE: The Temperat ure Rise Tables can also be used to est imat e the air handler airflow delivery. When using these tables for this
purpose set the room thermostat to maximum heat and allow the syst em to reach st eady st at e conditions. Insert two thermomet ers,
one in the ret urn air and one in the supply air. The temperat ure rise is t he supply air temperat ure minus the room air temperat ure.
Using the temperature rise calculated, CFM can be est imated from the TR formula above. See Technical M anual and/ or Service M anual
for more information.
3 5 6 8 10 15 19/20 25
800 1219233137
1000 9 1519253044
1200 8 1215212537 49 62
1400 7 1113182132 42 53
1600 6 9 12 15 19 28 37 46
1800 5 8 10 14 16 25 33 41
2000 5 7 9 121522 30 37
CFM
HEAT KIT NOMINAL kW
230/ 1/ 60 SUPPLY VOLTAGE - TEM P. RISE °F
Table 2
3568101519/2025
800 1118223035
1000 9 14 18 24 28 42
1200 7 12 15 20 24 35 47 59
1400 6 10 13 17 20 30 40 51
1600 6 9 11151827 35 44
1800 5 8 10131624 31 39
2000 4 7 9 12 14 21 28 35
CFM
HEAT KIT NOMINAL kW
220/ 1/ 60 SUPPLY VOLTAGE - TEM P. RISE °F
Table 3
3 5 6 8 10 15 19/20 25
800 1017212833
1000 8 1317222740
1200 7 1114192233 45 56
1400 6 1012161929 38 48
1600 5 8 10 14 17 25 33 42
1800 5 7 9 12 15 22 30 37
2000 4 7 8 11 13 20 27 33
CFM
HEAT KIT NOMINAL kW
208/ 1/ 60 SUPPLY VOLTAGE - TEM P. RISE °F
Table 4