Trane UH-PRC001-EN manual Additional Selection Data, Model P Nomenclature, Motor and Fan Speeds

Selection

Procedure

Model P Nomenclature																			Digit 15 – Fan Guard
UHP	A	0 4 2		P	4	C	A	A	1	T	A	R	C	A	D	B		E
123	4	5 6 7		8	9	10	11	12	13	14	15	16	17	18	19	20	21		Digit 16 – Unit Coating
Digits 1,2,3 – ProductType										Digit 10 – Design Sequence									Digit 17 – Diffuser
Digit 4 – Development Sequence										Digit 11 –Tube Material									Digit 18 – Manual Starter
Digits 5,6,7 – Unit Size										Digit 12 – Fin Material									Digit 19 – Speed Controller (115/60/1
Digit 8 – CoilType										Digit 13 –Voltage									standard motors)
Digit 9 – Fin Series										Digit 14 – MotorType									Digit 20 –Thermostats
																			Digit 21 – Subbase
Table SP-7 – Factors For Determining Steam Capacity Of Model P Projection Unit Heaters AtVarious Pressures AndTemperatures
	Table Based on 2 PSIG and 60 F Entering Air
	Steam													Temperature of Entering Air (F)
Pressure PSIG					-10			0		10		20		30		40		50	60	70	80	90	100
		0			1.49		1.41			1.33		1.25		1.18		1.11		1.03	0.96	0.90	0.83	0.76	0.69
		2			1.52		1.45			1.37		1.29		1.22		1.15		1.07	1.00	0.93	0.86	0.80	0.73
		5			1.58		1. 50			1.42		1.34		1.27		1.20		1.12	1.05	0.98	0.91	0.85	0.78
		10			1.64		1.57			1.49		1.41		1.34		1.27		1.19	1.12	1.05	0.98	0.91	0.85
Draw-			15		1.70		1.62			1.55		1.47		1.40		1.32		1.25	1.18	1.11	1.04	0.97	0.90
Through			20		1.75		1.67			1.60		1.52		1.45		1.37		1.30	1.23	1.16	1.09	1.02	0.96
Unit		30			1.83		1.75			1.68		1.61		1.53		1.46		1.39	1.32	1.25	1.18	1.11	1.04
		40			1.90		1.82			1.75		1.68		1.61		1.53		1.46	1.39	1.32	1.25	1.18	1.11
		50			1.96		1.87			1.81		1.74		1.67		1.59		1.52	1.45	1.38	1.31	1.24	1.17
		60			2.02		1.94			1.87		1.79		1.72		1.64		1.57	1.50	1.43	1.36	1.29	1.22
			70		2.07		1.99			1.92		1.84		1.76		1.69		1.62	1.55	1.47	1.40	1.33	1.27
		75			2.10		2.02			1.94		1.86		1.79		1.71		1.64	1.57	1.49	1.42	1.36	1.29

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.

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 inTable 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 smallerTrane Unit Heaters cataloged at 1550 RPM, the capacity data in the catalog may be applied to either 25 or 50 cycle service.

Table SP-8 – Factors for Determining Unit Heater Capacities at 25 or 50 Cycles

RPM		MultiplierTo Be AppliedTo
		60-Cycle 1100 RPM Ratings
25 CY	50 CY	BTU	CFM	HP
1425	1425	1.17	1.25	1.95
	950	.87	.833	.572
710	710	.7	.623	.242

Table SP-9 – Properties of Steam

Gauge Pressure	Temp.	Latent
Lbs.	F	Heat
2	219	965
5	227	960
10	239	952
15	250	945
20	259	939
25	267	933
30	274	928
40	287	919
50	298	911
60	307	904
70	316	897
75	320	891

18 UH-PRC001-EN