25
441 01 5003 01
Specifications are subject to change without notice
Table 8
PROPANE GAS MANIFOLD PRESSURE (in wc) For Models 140
HEATING VALUE
at ALTITUDE
BTU/CU. FT.
MEAN ELEVATION FEET ABOVE SEA LEVEL
0 to
2000
2001 to
3000
3001 to
4000
4001 to
5000
5001 to
6000
6001 to
7000
7001 to
8000
2500
10.0
8.7
9.0
9.0
8.5
10.0
10.0
Orifice Size
#54
#54
#55
#55
#55
#56
#56
Conversion: 1 in wc = .25 kPa
NOTE: Propane data is based on 1.53 specific gravity. For fuels with different specific gravity consult the National Fuel Gas Code ANSI Z223.1--2006/NFPA
54--2006 or National Standard Of Canada, Natural Gas And Propane Installation Code CSA B149.1--05.
NOTE:
Bold
number indicates factory shipped size.
NOTE:
The derating of these furnaces at 2% (Natural Gas) and 4%
(Propane Gas) has been tested and design--certified by CSA.
The burner orifice part nos. are as follows:
Orifice #41
1096942
Orifice #42
1011351
Orifice #43
1011377
Orifice #44
1011352
Orifice #45
1011353
Orifice #47
1011378
Orifice #46
1011744
Orifice #54
1011376
Orifice #55
1011354
Orifice #56
1011355
High Altitude Air Pressure Switch
The factory--installed pressure switch need NOT be changed for
any furnace installations from sea level up to and including 8,000
′
altitude.
Changing Orifices
1. After disconnecting power and gas supply to the furnace,
remove the burner compartment door, exposing the burner
compartment.
2. Disconnect gas line from gas valve so manifold can be
removed.
3. Disconnect wiring at gas valve. Be sure to note the proper
location of all electrical wiring before being disconnected.
4. Remove the four (4) screws holding the manifold and gas valve
to the manifold supports. Do not discard any screws. See
Figure 28.
5. Carefully remove the manifold assembly.
Figure 28
Manifold
Some Models may vary
25--25--00
6. Remove the orifices from the manifold and replace them with
proper sized orifices. See
Figure 29.
7. Tighten orifices so they are seated and gas--tight. See
Figure 29.
Figure 29
Clearances
Measure from face of orifice to the
back side of the manifold.
1.11
″
(28.2mm)
1.21
″
(30.8mm)
8. Reassemble all parts in reverse order as removed. Be sure to
engage the main burner orifices in the proper openings in the
burners.
9. After reassembling, turn gas on and check all joints for gas
leaks using a soapy solution. All leaks must be repaired
immediately.
Main Burner Flame Check
Allow the furnace to run approximately 10 minutes. Then inspect
the main burner flames. See
Figure 30
.
Check for the following (
Figure 30
):
•
Stable and blue flames. Dust may cause orange tips or wisps
of yellow, but flames
MUST NOT
have solid, yellow tips.
•
Flames extending directly from burner into heat exchanger.
•
Flames do
NOT
touch sides of heat exchanger
If any problems with main burner flames are noted, it may be
necessary to adjust gas pressures or check for drafts.
Main Burner
Burner Face
10--10--78
Figure 30
