17
Performance data (cont)
ECONOMIZER 1-in. FILTER PRESSURE DROP (in. wg)
MULTIPLICATION FACTORS
Example: 20 kW (at 240v) heater on 230v
= 20.0 (.92 mult factor)
= 18.4 kW capacity at 230 v
LEGEND
BF—Bypass Factor
Ewb—Entering Wet-Bulb
kW—Total Unit Power Input
SHC—Sensible Heat Capacity (1000 Btuh)
TC—Total Capacity (1000 Btuh) (net)
Edb—Entering Dry-Bulb
rh—Relative Humidity
Indicates Integrated Ratings
UNIT50JX
PRESSURE DROP
024-036
0.20
042-060
0.25
HEATER kW
RATING
VOLTAGE
DISTRIBUTION
V/3/60
MULTIPLICATION
FACTOR
240
200
208
230
240
.69
.75
.92
1.00
480
440
460
480
.84
.92
1.00
4. The SHC is based on 80 F edb temperature of air entering evaporator coil.
Below 80 F edb, subtract (corr factor x cfm) from SHC.
Above 80 F edb, add (corr factor x cfm) to SHC.
Correction Factor = 1.10 x (1 – BF) x (edb – 80).
5. Integrated capacity is maximum (instantaneous) capacity less the effect of frost
on the outdoor coil and the heat required to defrost it.
NOTES:
1. Ratings are net; they account for the effects of the evaporator-fan motor power
and heat.
2. Direct interpolation is permissible. Do not extrapolate.
3. The following formulas may be used:
C00093
Balance Point Worksheet
0
10
20
30
40
50
60
70
-10
0
10
17
20
30
40
47
50
60
Outdoor Air Temp (Deg F)
024
030
036
042
048
060
Based on Indoor Entering Air of 70 F and Rated CFM
Building Heat Loss
, 1000BTUH
Unit Integ
rated Heating Capacity (x1000BTUH)
sensible capacity (Btuh)
t
= t
ldb
edb
1.10 x cfm
t
= Wet-bulb temperature corresponding to enthalpy of air leaving
lwb
evaporator coil (h
)
lwb
total capacity (Btuh)
h
= h
lwb
ewb
4.5 x cfm
Where: h
= Enthalpy of air entering evaporator coil
ewb
