Owner’s manual, Installation, Continued) – Williams 2503531 User Manual
Page 9
9
201843
OWNER’S MANUAL
CAUTION: Never connect heater directly to the propane/LP supply.
This heater requires an external regulator (not supplied). Install the
external regulator between the heater and propane/LP supply.
The installer must supply an external regulator. The external regulator will reduce incoming
gas pressure. You must reduce incoming gas pressure to between 11 and 14 inches of water.
If you do not reduce incoming gas pressure, heater regulator damage could occur. Install
external regulator with the vent pointing down. Pointing the vent down protects it from
freezing rain or sleet.
Providing Gas Piping to Furnace
You must provide gas piping from gas source to furnace. The gas piping must be in a vertical
position where it connects to the furnace. This prevents interference with front cover
installation.
Consult your local gas company for proper routing of the gas lines.
Pipe size is determined by the length of pipe from the gas source to the furnace and the total
BTU load on the gas source.
Add the total BTUs required for all appliances connected to the gas source including this furnace.
Divide this number by 2500. This will give you the approximate cubic feet per hour needed.
Example:
40,000 BTU/Hr
+ 15,000 BTU/Hr for other gas appliances
55,000 BTU/Hr total
55,000
÷
2500 = 22
Locate 22 or higher on chart below.
According to the chart below, you should use 40 feet or less of 3/8" pipe, 125 feet
or less of 1/2" pipe, etc...
MINIMUM
IRON PIPE
SIZE
LENGTH OF PIPE (FEET)
10
20
30
40
50
60
70
80
90
100
125
150
175
200
3/8"
47
32
26
22
19
18
16
15
14
13
12
11
10
—
1/2"
87
61
48
42
37
33
30
28
26
25
22
20
18
17
3/4"
184
126
100
86
76
69
63
59
55
52
48
42
39
36
1"
344
232
189
162
142
129
119
112
106
99
86
79
73
66
1
1
/
4
"
696
484
391
331
291
265
245
232
212
202
182
166
149
139
1
1
/
2
"
1060
729
590
504
444
404
371
351
324
305
272
252
232
212
2"
2022
1392 1094
961
842
762
696
656
616
576
517
470
430
404
2
1
/
2
"
3182
2188 1790 1524 1326 1226 1127 1060
994
928
829
749
969
649
3"
5635
3911 3116 2718 2387 2154 1989 1856 1724 1657 1458 1326 1226 1127
4" 11602
7956 6431 5503 4906 4508 4110 3845 3580 3381 2983 2718 2519 2320
IMPORTANT:
Check gas line pressure at gas meter before connecting furnace to gas line. Gas
line pressure must be no less than 11 inches of water and no greater than 13 inches of water.
Gas pressures and input to the burners must not exceed the rated input and pressure shown on
the rating plate. For propane/LP gas, manifold pressure should be 10 inches of water. For
elevations above 2000 feet, reduce rating 4% for each 1000 feet above sea level (U.S.A. only).
INSTALLATION
(Continued)
Continued