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912SD: 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.
52
g. If clocked rate does not match required input from Step 1,
increase manifold pressure to increase input or decrease manifold
pressure to decrease input. Repeat steps b through e until correct
input is achieved. Re-install regulator seal cap on gas valve.
Table 19 – Orifice Size and Manifold Pressure (in. w.c.) for Gas
Input Rate
A11253A
- Orifice Size and Manifold Pressure (in. w.c.) for Gas
Input Rate (Cont.)
A11253B
3. Restore furnace to normal operating condition.
a. Turn gas valve ON/OFF switch to OFF.
b. Remove water column manometer or similar device from
manifold pressure tap.
c. Tighten set screw on manifold tower pressure tap with 3/32-in.
hex wrench, or if
⅛
-in. NPT plug was removed, apply pipe dope
sparingly to end of plug and re-install in the gas valve.
d. Turn gas valve ON/OFF switch to ON.
e. Check for gas leaks and verify furnace operation.
Adjust Temperature Rise
NOTE:
Blower door must be installed when taking temperature rise
reading. Leaving blower door off will result in incorrect temperature
measurements, due to possible changes in duct static pressure and
airflow.
This furnace must operate within the temperature rise ranges specified
on the furnace rating plate. Determine the air temperature as follows:
1. Place duct thermometers in return and supply ducts as close to
furnace as possible. Be sure thermometers do not “see” heat
S
A
G
L
A
R
U
T
A
N
F
O
Y
T
I
V
A
R
G
C
I
F
I
C
E
P
S
S
A
G
.
G
V
A
HEAT VALUE
0.58
0.60
0.62
0.64
AT ALTITUDE
Orifice
Manifold
Orifice
Manifold
Orifice
Manifold
Orifice
Manifold
(Btu/cu ft)
No.
Pressure
No.
Pressure
No.
Pressure
No.
Pressure
900
43
3.8
42
3.2
42
3.3
42
3.4
0
925
43
3.6
43
3.7
43
3.8
42
3.2
(0)
950
43
3.4
43
3.5
43
3.6
43
3.7
975
44
3.7
44
3.8
43
3.4
43
3.6
to
1000
44
3.5
44
3.6
44
3.8
43
3.4
1025
44
3.3
44
3.5
44
3.6
44
3.7
2000
1050
44
3.2
44
3.3
44
3.4
44
3.5
(610)
1075
45
3.7
45
3.8
44
3.3
44
3.4
1100
46
3.7
46
3.8
45
3.8
44
3.2
U.S.A.
800
42
3.4
42
3.5
42
3.6
42
3.7
2001 (611)
825
43
3.8
42
3.3
42
3.4
42
3.5
to
850
43
3.6
43
3.7
42
3.2
42
3.3
3000 (914)
875
43
3.4
43
3.5
43
3.7
43
3.8
900
44
3.7
44
3.8
43
3.5
43
3.6
Canada
925
44
3.5
44
3.6
44
3.8
43
3.4
2001 (611)
950
44
3.3
44
3.4
44
3.6
44
3.7
to
975
44
3.2
44
3.3
44
3.4
44
3.5
4500 (1372)
1000
44
3.0
44
3.1
44
3.2
44
3.3
775
42
3.3
42
3.4
42
3.5
42
3.6
3001
800
43
3.8
42
3.2
42
3.3
42
3.4
(915)
825
43
3.6
43
3.7
43
3.8
42
3.2
850
44
3.8
43
3.5
43
3.6
43
3.7
875
44
3.6
44
3.7
43
3.4
43
3.5
4000
900
44
3.4
44
3.5
44
3.7
44
3.8
(1219)
925
44
3.2
44
3.4
44
3.5
44
3.6
950
44
3.1
44
3.2
44
3.3
44
3.4
750
42
3.3
42
3.4
42
3.5
42
3.6
4001
775
43
3.7
43
3.8
42
3.3
42
3.4
(1220)
800
43
3.5
43
3.6
43
3.7
43
3.8
825
44
3.8
43
3.4
43
3.5
43
3.6
850
44
3.5
44
3.7
44
3.8
43
3.4
5000
875
44
3.3
44
3.5
44
3.6
44
3.7
(1524)
900
44
3.2
44
3.3
44
3.4
44
3.5
925
44
3.0
44
3.1
44
3.2
44
3.3
725
42
3.2
42
3.3
42
3.4
42
3.5
5001
750
43
3.7
43
3.8
42
3.2
42
3.3
(1525)
775
43
3.4
43
3.5
43
3.7
43
3.8
800
44
3.7
44
3.8
43
3.4
43
3.5
825
44
3.5
44
3.6
44
3.7
44
3.8
6000
850
44
3.3
44
3.4
44
3.5
44
3.6
(1829)
875
44
3.1
44
3.2
44
3.3
44
3.4
900
44
2.9
44
3.0
44
3.1
44
3.2
675
42
3.4
42
3.5
42
3.6
42
3.8
6001
700
42
3.2
42
3.3
42
3.4
42
3.5
(1830)
725
43
3.6
43
3.7
43
3.8
42
3.3
750
43
3.4
43
3.5
43
3.6
43
3.7
775
44
3.6
44
3.7
43
3.4
43
3.5
7000
800
44
3.4
44
3.5
44
3.6
44
3.7
(2133)
825
44
3.2
44
3.3
44
3.4
44
3.5
850
44
3.0
44
3.1
44
3.2
44
3.3
to
to
to
to
ALTITUDE
RANGE
ft (m)
U
.S
.A
.
an
d
C
an
ad
a
SINGLE
-
STAGE FURNACE
(TABULATED DATA BASED ON 20,000 BTUH PER BURNER, DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL)
U
.S.A
.
O
n
ly
U.
S
.A
.
O
n
ly
U.
S
.A
.
O
n
ly
U
.S.A
.
O
nly
U
.S.A
.
a
nd
C
a
na
da
WARNING
!
FIRE HAZARD
Failure to follow this warning could result in personal injury, death,
and/or property damage.
Manifold pressure tap set screw must be tightened and 1/8-in. NPT pipe
plug must be installed to prevent gas leaks.
CAUTION
!
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in:
-
Overheating the heat exchangers or condensing flue gases in
heat exchanger areas not designed for condensate.
-
Shortened furnace life
-
Component damage.
Temperature rise must be within limits specified on furnace rating plate.
Recommended operation is at midpoint of rise range or slightly above.
S
A
G
L
A
R
U
T
A
N
F
O
Y
T
I
V
A
R
G
C
I
F
I
C
E
P
S
S
A
G
.
G
V
A
HEAT VALUE
0.58
0.60
0.62
0.64
AT ALTITUDE
Orifice
Manifold
Orifice
Manifold
Orifice
Manifold
Orifice
Manifold
(Btu/cu ft)
No.
Pressure
No.
Pressure
No.
Pressure
No.
Pressure
ALTITUDE
RANGE
ft (m)
SINGLE
-
STAGE FURNACE
(TABULATED DATA BASED ON 20,000 BTUH PER BURNER, DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL)
650
42
3.4
42
3.5
42
3.6
42
3.7
7001
675
43
3.8
42
3.2
42
3.3
42
3.4
(2134)
700
43
3.5
43
3.7
43
3.8
42
3.2
725
44
3.8
43
3.4
43
3.5
43
3.6
750
44
3.5
44
3.7
44
3.8
43
3.4
8000
775
44
3.3
44
3.4
44
3.5
44
3.7
(2438)
800
44
3.1
44
3.2
44
3.3
44
3.4
825
44
2.9
44
3.0
44
3.1
44
3.2
625
42
3.4
42
3.5
42
3.6
42
3.7
8001
650
43
3.8
42
3.2
42
3.3
42
3.4
(2439)
675
43
3.5
43
3.6
43
3.7
42
3.2
700
44
3.7
43
3.4
43
3.5
43
3.6
725
44
3.5
44
3.6
44
3.7
44
3.8
9000
750
44
3.3
44
3.4
44
3.5
44
3.6
(2743)
775
44
3.0
44
3.2
44
3.3
44
3.4
9001
600
42
3.3
42
3.4
42
3.6
42
3.7
(2744)
625
43
3.7
42
3.2
42
3.3
42
3.4
650
43
3.5
43
3.6
43
3.7
43
3.8
675
44
3.7
44
3.8
43
3.4
43
3.5
10000
700
44
3.4
44
3.5
44
3.7
44
3.8
(3048)
725
44
3.2
44
3.3
44
3.4
44
3.5
* Orifice numbers shown in
BOLD
are factory-installed.
to
to
to
U.
S
.A.
On
ly
U.
S
.A.
On
ly
U.
S
.A.
On
ly