19
UH-PRC001-EN
Selection
Procedure
Unit
Steam Pressure (PSI)
Size
2
5
10
50
75
146-P-L
18.0
17.5
17.5
15.0
14.0
22.5 22.0
21.5 18.5 18.0
166-P
18.0
17.5
17.0
14.5
14.0
22.5 22.0
21.5 19.0 18.0
166-P-L
22.0
21.5
21.0
18.5
17.5
27.5 27.0 26.5 23.5 22.5
202-P
22.0
21.5
21.0
18.5
17.5
27.5 27.0 26.5 24.0 23.0
202-P-L
25.5
250
24.5
22.0
21.0
31.5 31.0 30.5 27.0 26.0
252-P
20.0
19.5
19.0
17.0
16.0
25.0 24.0 23.5 20.5 19.5
252-P-L
24.0
23.5
23.0
20.0
19.0
29.5 28.5 28.0 24.5 23.5
280-P
21.0
20.5
20.0
17.5
17.0
26.0 25.5 25.0 22.0 21.0
280-P-L
25.5
25.0
24.5
21.0
20.0
32.0 31.0 30.0 26.0 25.0
336-P
24.0
23.0
22.0
20.0
19.0
30.0 29.0 28.0 25.0 24.0
336-P-L
29.0
28.5
28.0
25.0
24.0
36.0 35.0 34.0 30.0 29.0
384-P
28.5
28.0
27.5
24.0
23.0
35.5 35.0 34.0 30.0 29.0
384-P-L
32.5
31.5
30.5
27.5
26.5
41.0 40.0 39.0 35.0 33.5
500-P
29.5
29.0
28.5
25.0
24.0
36.5 36.0 35.5 32.0 30.5
500-P-L
35.0
34.0
33.0
29.0
28.0
43.5 42.5
41.5 35.0 34.0
600-P
34.0
33.0
32.0
28.0
27.0
42.5 41.5 40.5 36.0 34.5
600-P-L
37.0
36.0
35.0
31.0
30.0
46.5 45.5 44.5 39.0
37.0
720-P
38.5
37.5
36.5
32.0
30.5
48.0
47.0 46.0 40.0 39.0
720-P-L
42.5
41.5
40.5
35.0
33.5
53.0 52.0
51.0 44.0 42.0
Table SP-10 - Maximum Mounting Heights in Feet for Model P Unit Heaters
with and without Louver Cone Diffuser
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
10.5 10.0
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
11.5
11.0
11.0
9.5
9.0
64-P-L
15.0
14.5
14.5
12.5
12.0
19.0 18.5
18.5 16.5 16.0
64-P-L LS
11.5
11.0
11.0
9.5
8.0
14.0 13.5
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
13.5 13.0
13.0 11.5
11.0
80-P-L
18.0
17.5
17.5
15.0
14.0
22.0 21.0
21.0 19.0 18.0
80-P-L LS
13.0
12.5
12.0
11.0
10.5
17.0 16.5
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
13.5 13.0
13.0 12.0
11.5
102-P-L
17.5
17.0
16.5
15.0
14.5
21.5 21.0 20.5 18.5
17.5
102-P-L LS
15.0
14.5
14.5
13.0
12.5
18.5 18.0
18.0 16.0 15.0
122-P
16.0
15.5
15.5
14.0
13.5
19.5 19.0
18.5 17.0 16.0
122-P-L
21.0
20.5
20.0
17.5
17.0
26.0 25.5 25.0 22.5 21.5
146-P
15.5
15.0
14.5
13.0
12.0
19.0 18.5
18.0 16.0 15.5
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.
Hot Water Selection Example
Selection Procedure
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 to Table 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
the unit which will provide 89.8 MBH at
6.53 GPM. In this example, the selection
indicates a Model S 126W2 unit heater,
from Table 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)
Содержание UH-PRC001-EN
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