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Installer's
Guide
@
CORRECT METHOD OF CHECKING DIRECT VENT MANIFOLD
PRESSURE WITH BURNER BOX REFERENCED
..........
2.
_i--r ---_
@
Separate
the tube
at the unit Tee and
reconnect
with a
short piece of field
supplied
tube and
another Tee with
the "U" Manometer
attached,
Be sure to reconnect
unit tubing
to odginal
position
after testing
the manifold
pressure!
F,.,dsupp,,.d
L'__.
barb fitting
with manometer
tube is
attached
to the "OUTLET
PRESSURE
TAP" on the
outlet side of the gas valve.
k. Using
a leak detection
solution
or soap suds,
check
fl)r
leaks
at plug
or pressure
boss screw.
Replace and/or tighten all plugs removed or loosened when
adjusting gas pressure. Leak check the fittings before
placing the furnace into regular service. Failure to follow
this warning could result in fire, explosion, or property
damage.
NOTE:
The manifold
pressure
must be referenced
to the burner
box. The burner box pressure
tap equalizes
the gas valve
pressure
regulator.
Manifold
pressure
is checked
by
installing
a tee (field supplied)
in the tubing, between
the tee
coming
from the burner box tube and the gas valve, in
addition
to the regular
gas valve pressure
tap on the outlet
side of the gas valve. See Figure
49.
Replace manifold pressure tap threaded plug and leak
check after checking/adjusting
manifold gas pressure.
Table
11 lists the
main
burner
orifices
used with
the
fllrnace.
If a change
of orifices
is required
to correct
the fllrnace
input
rating
reler
to Table
14.
TABLE 12
FINAL
MANIFOLD
PRESSURE
SETTINGS
FUEL
PRESSURE
NATURAL GAS
3.5" W.C.
LP GAS
11.0" W.C.
HIGH
ALTITUDE
DERATE
Input
ratings
(BTUH)
of these
fllrnaces
are
based
on sea level
operation
an(] should
not be change(]
at elevations
up to 2,000
ft.
TABLE 13
GAS FLOW IN CUBIC FEET PER HOUR
2 CUBIC FOOT DIAL
SEC.
FLOW
SEC.
FLOW
SEC.
FLOW
SEC.
FLOW
8
900
29
248
50
144
82
88
9
800
30
240
51
141
84
86
10
720
31
232
52
138
86
84
11
655
32
225
53
136
88
82
12
600
33
218
54
133
90
80
13
555
34
212
55
131
92
78
14
514
35
206
56
129
94
76
15
480
36
200
57
126
96
75
16
450
37
195
58
124
98
73
17
424
38
189
59
122
100
72
18
400
39
185
60
120
104
69
19
379
40
180
62
116
108
67
20
360
41
176
64
112
112
64
21
343
42
172
66
109
116
62
22
327
43
167
68
106
120
60
23
313
44
164
70
103
124
58
24
300
45
160
72
100
128
56
25
288
46
157
74
97
132
54
26
277
47
153
76
95
136
53
27
267
48
150
78
92
140
51
28
257
49
147
80
90
144
50
28
18-CD19D6-27
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