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PG80MSU: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
26
Table 14 – Altitude Derate Multiplier for U.S.A
.
Furnace gas input rate on rating plate is for installations at altitudes up to
2,000 ft. (610 M). Furnace input rate must be within +/-2 percent of
furnace rating plate input.
2. Determine the correct outlet gas pressure adjustment.
a. Obtain average yearly gas heat value (at installed altitude) from
local gas supplier.
b. Obtain average yearly gas specific gravity from local gas
supplier.
c. Find closest natural gas heat value and specific gravity in
through
d. Follow heat value and specific gravity lines to point of
intersection to find outlet pressure setting for proper operation.
3. Check Inlet Gas Pressure
The inlet gas pressure must be checked with the furnace operating. This
is necessary to make sure the inlet gas pressure does not fall below the
minimum pressure of 4.5 in. w.c.
a. Make sure the gas supply is turned off to the furnace and at the
electric switch on the gas valve
b. Loosen set screw on inlet tower pressure tap no more than one
full turn with a 3/32−in. hex wrench or remove the 1/8−in. NPT
plug from the inlet pressure tap on the gas valve.
c. Connect a manometer to the inlet pressure tap on gas valve.
d. Turn on furnace power supply.
e. Turn gas supply manual shutoff valve to ON position.
f. Turn furnace gas valve switch to ON position.
g. Jumper R and W thermostat connections at the furnace control
board.
h. When main burners ignite, confirm inlet gas pressure is between
4.5 in. w.c. (1125 Pa) and 13.6 in. w.c. (3388 Pa).
i. Remove jumper across thermostat connections to terminate call
for heat. Wait until the blower off delay is completed.
j. Turn furnace gas valve electric switch to OFF position.
k. Turn gas supply manual shutoff valve to OFF position.
l. Turn off furnace power supply.
m.Remove manometer from the inlet pressure tap of the gas valve.
n. Tighten set screw on inlet tower pressure tap with 3/32−in. hex
wrench, or if 1/8−in. NPT plug was removed, apply pipe dope
sparingly to end of plug and reinstall in the gas valve
4. Adjust gas valve outlet pressure determined in Step 2 to obtain
correct input rate.
a. Turn gas valve ON/OFF switch to OFF.
b. Loosen set screw on outlet tower pressure tap no more than one
full turn with a 3/32 in. hex wrench, see
.
c. Connect a water column manometer or similar device to pressure
tap on the gas valve.
d. Turn gas valve ON/OFF switch to ON.
e. Manually close blower door switch.
f. Set thermostat to call for heat.
g. Remove regulator seal cap and turn regulator adjusting screw
counterclockwise (out) to decrease input rate of clockwise (in) to
increase input rate.
h. Install regulator seal cap.
i. Leave manometer or similar device connected and proceed to
next step.
NOTE:
If orifice hole appears damaged or it is suspected to have been
redrilled, check orifice hole with a numbered drill bit of correct size.
Never redrill an orifice. A burr-free and properly sized orifice hole is
essential for proper flame characteristics.
Table 15 – Gas Rate (Cu Ft./Hr.)
5. Verify natural gas input rate by clocking meter.
NOTE:
Gas valve regulator adjustment cap must be in place for proper
input to be clocked.
a. Turn off all other gas appliances and pilots served by the meter.
b. Run furnace for 3 minutes in heating operation.
c. Measure time (in seconds) for gas meter to complete 1 revolution
and note reading. The 2 or 5 cubic feet dial provides a more
accurate measurement of gas flow.
d. Refer to
ALTITUDE
(FT. / M)
PERCENT
OF
DERATE
DERATE
MULTIPLIER
FACTOR
*
*. Derate multiplier factors are based on midpoint altitude for altitude range
0–2000 (0-610)
0
1.00
2001–3000 (610-914)
4-6
0.95
3001–4000 (914-1219)
6-8
0.93
4001–5000 (1219-1524)
8-10
0.91
5001–5400 (1525-1646)
10-11
0.90
WARNING
!
FIRE HAZARD
Failure to follow this warning could result in personal injury, death,
and/or property damage.
Inlet pressure tap set screw must be tightened and 1/8-in. NPT pipe
plug must be installed to prevent gas leaks.
SECONDS
FOR 1 REV
SIZE OF TEST DIAL SECONDS
FOR 1 REV
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
50
72
144 360
11
327
655 1636
51
71
141 355
12
300
600 1500
52
69
138 346
13
277
555 1385
53
68
136 340
14
257
514 1286
54
67
133 333
15
240
480 1200
55
65
131 327
16
225
450 1125
56
64
129 321
17
212
424 1059
57
63
126 316
18
200
400 1000
58
62
124 310
19
189
379
947
59
61
122 305
20
180
360
900
60
60
120 300
21
171
343
857
62
58
116 290
22
164
327
818
64
56
112 281
23
157
313
783
66
54
109 273
24
150
300
750
68
53
106 265
25
144
288
720
70
51
103 257
26
138
277
692
72
50
100 250
27
133
267
667
74
48
97
243
28
129
257
643
76
47
95
237
29
124
248
621
78
46
92
231
30
120
240
600
80
45
90
225
31
116
232
581
82
44
88
220
32
113
225
563
84
43
86
214
33
109
218
545
86
42
84
209
34
106
212
529
88
41
82
205
35
103
206
514
90
40
80
200
36
100
200
500
92
39
78
196
37
97
195
486
94
38
76
192
38
95
189
474
96
38
75
188
39
92
185
462
98
37
74
184
40
90
180
450
100
36
72
180
41
88
176
439
102
35
71
178
42
86
172
429
104
35
69
173
43
84
167
419
106
34
68
170
44
82
164
409
108
33
67
167
45
80
160
400
110
33
65
164
46
78
157
391
112
32
64
161
47
76
153
383
116
31
62
155
48
75
150
375
120
30
60
150
49
73
147
367