5750149-UIM-D-1219
32
Johnson Controls Ducted Systems
ADJUSTMENT OF MANIFOLD GAS PRESSURE &
INPUT RATE
Inlet and manifold gas pressure may be measured by connecting the
“U” tube manometer to the gas valve with a piece of tubing. Follow the
appropriate section in the instructions below. Refer to Figure 39 for the
locations of the pressure ports on the gas valve.
Turn gas off at the ball valve or gas cock on gas supply line
before the gas valve. Find the pressure ports on the gas
valve marked Out P and In P.
1.
The manifold pressure must be taken at the port marked OUT P.
2.
The gas line pressure must be taken at the port marked IN P.
3.
Using a 3/32” (2.4 mm) hex head wrench, loosen the set screw by
turning it 1 turn counter clockwise. DO NOT REMOVE THE SET
SCREW FROM THE PRESSURE PORT.
Read the inlet gas pressure
Connect the positive side of the manometer to the IN P Tap on the gas
valve. Do not connect any tubing to the negative side of the manometer,
as it will reference atmospheric pressure. Refer to Figure 40 for connec-
tion details.
1.
Turn gas and electrical supplies on and follow the operating instruc-
tions to place the unit back in operation.
Table 15:
Gas Rate (CU FT/HR) at Full Input
Seconds For
1 Revolution
Size of Test Dial
Seconds For
1 Revolution
Size of Test Dial
1 Cu Ft
2 Cu Ft
5 Cu Ft
1 Cu Ft
2 Cu Ft
5 Cu Ft
10
360
720
1800
55
65
131
327
11
327
655
1636
56
64
129
321
12
300
600
1500
57
63
126
316
13
277
555
1385
58
62
124
310
14
257
514
1286
59
61
122
305
15
240
480
1200
60
60
120
300
16
225
450
1125
62
58
116
290
17
212
424
1059
64
56
112
281
18
200
400
1000
66
54
109
273
19
189
379
947
68
53
106
265
20
180
360
900
70
51
103
257
21
171
343
857
72
50
100
250
22
164
327
818
74
48
97
243
23
157
313
783
76
47
95
237
24
150
300
750
78
46
92
231
25
144
288
720
80
45
90
225
26
138
277
692
82
44
88
220
27
133
267
667
84
43
86
214
28
129
257
643
86
42
84
209
29
124
248
621
88
41
82
205
30
120
240
600
90
40
80
200
31
116
232
581
92
39
78
196
32
113
225
563
94
38
76
192
33
109
218
545
96
38
75
188
34
106
212
529
98
37
74
184
35
103
206
514
100
36
72
180
36
100
200
500
102
35
71
178
37
97
195
486
104
35
69
173
38
95
189
474
106
34
68
170
39
92
185
462
108
33
67
167
40
90
180
450
110
33
65
164
41
88
176
439
112
32
64
161
42
86
172
429
116
31
62
155
43
84
167
419
120
30
60
150
44
82
164
409
124
29
58
145
45
80
160
400
128
28
56
141
46
78
157
391
133
27
54
135
47
76
153
383
138
26
52
130
48
75
150
375
144
25
50
125
49
73
147
367
150
24
48
120
50
72
144
360
157
23
46
115
51
71
141
355
164
22
44
110
52
69
138
346
171
21
42
105
53
68
136
340
180
20
40
100
54
67
133
333
Table 16:
Inlet Gas Pressure Range
INLET GAS PRESSURE RANGE
Natural Gas
Propane (LP)
Minimum
4.5” w.c. (1.12 kPa)
8.0” w.c. (1.99 kPa)
Maximum
10.5” w.c. (2.61 kPa)
13.0” w.c. (3.24 kPa)