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PG80MSU: Installation, Start-up, Operating and Service and Maintenance Instructions
Table 14 – Altitude Derate Multiplier for U.S.A
.
ALTITUDE
(FT. / M)
0–2000 (0-610)
2001–3000 (610-914)
3001–4000 (914-1219)
4001–5000 (1219-1524)
5001–5400 (1525-1646)
*. Derate multiplier factors are based on midpoint altitude for altitude range
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
Table 16
through
Table
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
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.
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.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
PERCENT
DERATE
OF
MULTIPLIER
DERATE
FACTOR
0
1.00
4-6
0.95
6-8
0.93
8-10
0.91
10-11
0.90
19.
Fig.
21.
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.
SIZE OF TEST DIAL
SECONDS
FOR 1 REV
1 Cu
Ft.
10
360
11
327
300
12
277
13
14
257
15
240
225
16
212
17
200
18
19
189
20
180
171
21
164
22
157
23
24
150
25
144
138
26
133
27
129
28
29
124
30
120
116
31
113
32
109
33
34
106
35
103
100
36
97
37
95
38
39
92
40
90
88
41
86
42
84
43
44
82
45
80
78
46
76
47
75
48
49
73
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
Table 15
26
Table 15 – Gas Rate (Cu Ft./Hr.)
SECONDS
2 Cu
5 Cu
FOR 1 REV
Ft.
Ft.
50
720
1800
51
655
1636
600
1500
52
555
1385
53
514
1286
54
55
480
1200
450
1125
56
424
1059
57
400
1000
58
379
947
59
60
360
900
343
857
62
327
818
64
313
783
66
300
750
68
70
288
720
277
692
72
267
667
74
257
643
76
248
621
78
80
240
600
232
581
82
225
563
84
218
545
86
212
529
88
90
206
514
200
500
92
195
486
94
189
474
96
185
462
98
100
180
450
176
439
102
172
429
104
167
419
106
164
409
108
110
160
400
157
391
112
153
383
116
150
375
120
147
367
for cubic ft. of gas per hr.
SIZE OF TEST
DIAL
1 Cu
2 Cu
5 Cu
Ft.
Ft.
Ft.
72
144
360
71
141
355
69
138
346
68
136
340
67
133
333
65
131
327
64
129
321
63
126
316
62
124
310
61
122
305
60
120
300
58
116
290
56
112
281
54
109
273
53
106
265
51
103
257
50
100
250
48
97
243
47
95
237
46
92
231
45
90
225
44
88
220
43
86
214
42
84
209
41
82
205
40
80
200
39
78
196
38
76
192
38
75
188
37
74
184
36
72
180
35
71
178
35
69
173
34
68
170
33
67
167
33
65
164
32
64
161
31
62
155
30
60
150
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