Trane UH-PRC001-EN HotWater Selection Example, Selection Procedure, Step, Determine GPM, 95000 =

Selection Procedure

Table SP-10 - Maximum Mounting Heights in Feet for Model P Unit Heaters with and without Louver Cone Diffuser

HotWater Selection Example

Selection Procedure

Unit		Steam Pressure (PSI)
Size	2	5	10	50	75
42-P	10.5	10.0	10.0	9.0	8.0
	12.5	12.0	12.0	11.0	10.0
42-P LS*	8.0	8.0	8.0	8.0	8.0
	9.0	8.5	8.5	8.0	8.0
42-P-L**	12.5	12.0	12.0	10.5	9.5
	14.5	14.0	13.5	12.0	11.5
42-P-L LS	9.0	8.5	8.5	8.0	8.0

10.510.0 10.0 9.0 8.5

64-P 12.0 11.5 11.5 10.0 9.5

	14.5	14.0	14.0	12.0	11.5
64-P LS	9. 5	9.0	9.0	8.0	8.0

11.511.0 11.0 9.5 9.0

64-P-L 15.0 14.5 14.5 12.5 12.0

19.018.5 18.5 16.5 16.0

64-P-L LS 11.5 11.0 11.0 9.5 8.0

14.013.5 13.5 12.0 11.5

80-P 15.0 14.5 14.0 12.0 4.5

	18.5	18.0	17.5	15.5	13.5
80-P LS	11.0	10.5	10.5	9.0	8.5

13.513.0 13.0 11.5 11.0

80-P-L 18.0 17.5 17.5 15.0 14.0

22.021.0 21.0 19.0 18.0

80-P-L LS 13.0 12.5 12.0 11.0 10.5

17.016.5 16.0 14.0 13.5

102-P 14.0 13.5 13.0 11.5 11.0

	17.0	16.5	16.0	14.0	13.5
102-P LS	11.0	10.5	10.5	9.5	9.0

13.513.0 13.0 12.0 11.5

102-P-L 17.5 17.0 16.5 15.0 14.5

21.521.0 20.5 18.5 17.5 102-P-L LS 15.0 14.5 14.5 13.0 12.5

18.518.0 18.0 16.0 15.0

122-P 16.0 15.5 15.5 14.0 13.5

19.519.0 18.5 17.0 16.0

122-P-L 21.0 20.5 20.0 17.5 17.0

26.025.5 25.0 22.5 21.5

146-P 15.5 15.0 14.5 13.0 12.0

19.018.5 18.0 16.0 15.5

Unit		Steam Pressure (PSI)
Size	2	5	10	50	75
146-P-L	18.0	17.5	17.5	15.0	14.0

22.522.0 21.5 18.5 18.0

166-P 18.0 17.5 17.0 14.5 14.0

22.522.0 21.5 19.0 18.0

166-P-L 22.0 21.5 21.0 18.5 17.5

27.527.0 26.5 23.5 22.5

202-P 22.0 21.5 21.0 18.5 17.5

27.527.0 26.5 24.0 23.0

202-P-L 25.5 250 24.5 22.0 21.0

31.531.0 30.5 27.0 26.0

252-P 20.0 19.5 19.0 17.0 16.0

25.024.0 23.5 20.5 19.5

252-P-L 24.0 23.5 23.0 20.0 19.0

29.528.5 28.0 24.5 23.5

280-P 21.0 20.5 20.0 17.5 17.0

26.025.5 25.0 22.0 21.0

280-P-L 25.5 25.0 24.5 21.0 20.0

32.031.0 30.0 26.0 25.0

336-P 24.0 23.0 22.0 20.0 19.0

30.029.0 28.0 25.0 24.0

336-P-L 29.0 28.5 28.0 25.0 24.0

36.035.0 34.0 30.0 29.0

384-P 28.5 28.0 27.5 24.0 23.0

35.535.0 34.0 30.0 29.0

384-P-L 32.5 31.5 30.5 27.5 26.5

41.040.0 39.0 35.0 33.5

500-P 29.5 29.0 28.5 25.0 24.0

36.536.0 35.5 32.0 30.5

500-P-L 35.0 34.0 33.0 29.0 28.0

43.542.5 41.5 35.0 34.0

600-P 34.0 33.0 32.0 28.0 27.0

42.541.5 40.5 36.0 34.5

600-P-L 37.0 36.0 35.0 31.0 30.0

46.545.5 44.5 39.0 37.0

720-P 38.5 37.5 36.5 32.0 30.5

48.047.0 46.0 40.0 39.0

720-P-L 42.5 41.5 40.5 35.0 33.5

53.052.0 51.0 44.0 42.0

Select the proper size of unit heater for whatever application desired, as illustrated by the following examples.

Example 1:

Select a Model S horizontal unit heater to deliver 95 MBH with 220°F entering water temperature (EWT), 70°F entering air temperature (EAT) and a 30°F water temperature drop (WTD).

Step 1.
Determine GPM:
GPM = Btu/hr =		95000 = 6.53
	(485)WTD	485 x 30

Step 2.

Refer toTable SP-11 to select the conversion factor at 220° EWT and 70° EAT. Factor is 1.058.

Step 3.

Determine equivalent MBH at standard conditions (200° EWT, 60° EAT).

Equiv. MBH = MBH = 95 = 89.8 Factor 1.058

Step 4.

Select unit size by entering the hot water tables at the 200 °F EWT column. Select

Notes:

*LS = Low speed.

**PL = Model P low final temperature model with all air ports open.

Figures in bold face show maximum mounting height with louver cone diffusers set vertically.

To meet CSA and OSHA requirements, Model P Unit Heaters mounted lower than 8.0 ft. from the floor must be equipped with an OSHA fan guard. Above table based on 60 F entering air temperature. In providing for the use of diffusers, it must be remembered that adjustment of a LCD to deflect air toward horizontal immediately lowers the mounting height limit.

the unit which will provide 89.8 MBH at

6.53GPM. In this example, the selection indicates a Model S 126W2 unit heater, fromTable PD-2, page 28.

To determine the actual capacity of this Model S 126W2 at operating conditions (220° EWT and 70° EAT) proceed as follows.

Step 1.

Determine the MBH at 6.53 GPM by interpolation in the 200° column. (In this case 90.8 MBH.) Multiply this MBH by the conversion factor 90.8 MBH x 1.058 = 96 MBH.

Step 2.

The GPM remains constant = 6.53 GPM.

Step 3.

Calculate the water temperature drop

WTD = Btu/hr =		96000 = 30.3
	GPM x 485	(6.53) (485)

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