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Model P Nomenclature
UHP
A
0 4 2 P
4
C
123
4
5 6 7 8
9
10 11 12 13 14 15 16 17 18 19 20 21
Digits 1,2,3 – Product Type
Digit 4 – Development Sequence
Digits 5,6,7 – Unit Size
Digit 8 – Coil Type
Digit 9 – Fin Series
Table SP-7 – Factors For Determining Steam Capacity Of Model P Projection Unit Heaters At Various Pressures And Temperatures
Table Based on 2 PSIG and 60 F Entering Air
Steam
Pressure PSIG
-10
0
1.49
2
1.52
5
1.58
10
1.64
Draw-
15
1.70
Through
20
1.75
Unit
30
1.83
40
1.90
50
1.96
60
2.02
70
2.07
75
2.10
Note:
To determine the Btu per hour capacity of a Model P projection unit heater at any steam pressure and entering air temperature, multiply rated capacity at 2 psig steam 60 F entering air (Table
SP-5) by factor from above table.
Additional Selection Data
Motor and Fan Speeds
Motor and fan speeds are selected to
provide efficient performance. The
solid-state speed control will provide an
infinite number of speeds between the
highest and the lowest cataloged fan
speeds. The speed control is not
calibrated in specific fan speeds. For use
on units with 115 volt/60 cycle/
1 phase, 1/8 hp and smaller standard
motors only.
Standard and Bypass Units
Standard models meet most
requirements and are most economical.
Bypass units meet conditions as
mentioned above, and are also used
where low final temperature is specified.
18
Selection
Procedure
A
A
1
T
A
R
C
Digit 10 – Design Sequence
Digit 11 – Tube Material
Digit 12 – Fin Material
Digit 13 – Voltage
Digit 14 – Motor Type
0
10
20
1.41
1.33
1.25
1.45
1.37
1.29
1. 50
1.42
1.34
1.57
1.49
1.41
1.62
1.55
1.47
1.67
1.60
1.52
1.75
1.68
1.61
1.82
1.75
1.68
1.87
1.81
1.74
1.94
1.87
1.79
1.99
1.92
1.84
2.02
1.94
1.86
25 and 50 Cycle Unit Heat Capacities
Table SP-8 shows the Btu, cfm, and the
hp required on unit heaters when
operated on 25 or 50 cycle circuits.
The multipliers in Table SP-8 may be
applied to standard 60 cycle unit
capacities to determine the capacities of
the same unit when operating on
25 or 50 cycle current. These multipliers
may be used on units cataloged at
1050 to 1150 RPM.
For the smaller Trane Unit Heaters
cataloged at 1550 RPM, the capacity data
in the catalog may be applied to either
25 or 50 cycle service.
Digit 15 – Fan Guard
A D B
E
Digit 16 – Unit Coating
Digit 17 – Diffuser
Digit 18 – Manual Starter
Digit 19 – Speed Controller (115/60/1
standard motors)
Digit 20 – Thermostats
Digit 21 – Subbase
Temperature of Entering Air (F)
30
40
50
60
1.18
1.11
1.03
0.96
1.22
1.15
1.07
1.00
1.27
1.20
1.12
1.05
1.34
1.27
1.19
1.12
1.40
1.32
1.25
1.18
1.45
1.37
1.30
1.23
1.53
1.46
1.39
1.32
1.61
1.53
1.46
1.39
1.67
1.59
1.52
1.45
1.72
1.64
1.57
1.50
1.76
1.69
1.62
1.55
1.79
1.71
1.64
1.57
Table SP-8 – Factors for Determining Unit
Heater Capacities at 25 or 50 Cycles
25 CY
1425
710
Table SP-9 – Properties of Steam
70
80
90
0.90
0.83
0.76
0.93
0.86
0.80
0.98
0.91
0.85
1.05
0.98
0.91
1.11
1.04
0.97
1.16
1.09
1.02
1.25
1.18
1.11
1.32
1.25
1.18
1.38
1.31
1.24
1.43
1.36
1.29
1.47
1.40
1.33
1.49
1.42
1.36
Multiplier To Be Applied To
RPM
60-Cycle 1100 RPM Ratings
50 CY
BTU
CFM
1425
1.17
1.25
950
.87
.833
710
.7
.623
Gauge Pressure
Temp.
Lbs.
F
2
219
5
227
10
239
15
250
20
259
25
267
30
274
40
287
50
298
60
307
70
316
75
320
UH-PRC001-EN
100
0.69
0.73
0.78
0.85
0.90
0.96
1.04
1.11
1.17
1.22
1.27
1.29
HP
1.95
.572
.242
Latent
Heat
965
960
952
945
939
933
928
919
911
904
897
891
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