31
441 01 2611 06
MANIFOLD PRESSURE AND ORIFICE SIZE FOR HIGH ALTITUDE APPLICATIONS
NATURAL GAS MANIFOLD PRESSURE (²
²²
² w.c.)
MEAN ELEVATION FEET ABOVE SEA LEVEL
HEATING
VALUE
0to
2000
2001 to
3000
3001 to
4000
4001 to
5000
5001 to
6000
6001 to
7000
7001 to
8000
at ALTITUDE
BTU/CU. FT.
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
700 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 41 3.7
725 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 41 3.7 41 3.4
750 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 41 3.5 42 3.6
775 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 41 3.6 42 3.6 42 3.3
800 -- -- -- -- -- -- -- -- -- -- -- -- 41 3.6 42 3.7 42 3.4 42 3.1
825 -- -- -- -- -- -- -- -- 41 3.7 41 3.4 42 3.5 42 3.2 42 2.9
850 -- -- -- -- -- -- -- -- 41 3.5 42 3.6 42 3.3 42 3.0 42 2.8
875 -- -- -- -- 41 3.6 42 3.6 42 3.4 42 3.1 42 2.8 42 2.6
900 -- -- -- -- 42 3.7 42 3.4 42 3.2 42 2.9 42 2.7 42 2.5
925 41 3.7 42 3.5 42 3.3 42 3.0 42 2.8 42 2.5 42 2.3
950 41 3.5 42 3.3 42 3.1 42 2.9 42 2.6 42 2.4 43 2.7
975 42 3.7 42 3.2 42 2.9 42 2.7 42 2.5 42 2.3 43 2.6
1000 42 3.5 42 3.0 42 2.8 42 2.6 42 2.4 43 2.7 43 2.4
1050 42 3.2 42 2.7 42 2.5 42 2.3 43 2.6 -- -- -- -- -- -- -- --
1100 42 2.9 42 2.5 42 2.3 43 2.6 -- -- -- -- -- -- -- -- -- -- -- --
NOTE: Natural gas data is based on 0.60 specific gravity. For fuels with different specific gravity consult the National Fuel Gas Code ANSI
Z223.1--2002/NFPA 54--2002 or National Standard of Canada, Natural Gas And Propane Installation Code CSA B149.1--00.
Table 8 LPG or PROPANE GAS MANIFOLD PRESSURE (²
²²
² w.c.)
HEATING VALUE
MEAN ELEVATION FEET ABOVE SEA LEVEL
at ALTITUDE
BTU/CU. FT.
0to
2000
2001 to
3000
3001 to
4000
4001 to
5000
5001 to
6000
6001 to
7000
7001 to
8000
2500 10.0 10.0 9.0 10.0 9.4 8.5 10.0
Orifice Siz e #54 #54 #54 #55 #55 #55 #56
NOTE:Propanedataisbasedon1.53specificgravity. ForfuelswithdifferentspecificgravityconsulttheNationalFuelGasCodeANSIZ223.1--2002/NFPA
54--2002 or National Standard Of Canada, Natural Gas And Propane Installation Code CSA B149.1--00.
NOTE: The derating of these furnaces at 2% (Natural Gas) and
4%(PropaneGas)has been tested anddesign--certified byCSA.
High Altitude Air Pressure Switch
The factory--installed pressure switch need NOT be changed for
anyfurnaceinstallationsfromsealevelupto and including8,000¢
altitude
CARBON MONOXIDE POISONING HAZARD.
Failure to follow t his warning could result in
property damage, personal injury and/or death.
NOx inserts for usewith NaturalGasunits ONLY. If
LP Gas is required, NOx inserts must be
removed.
!
WARNING
Changing Orifices
1. After disconnecting power and gas supply to the furnace, re-
move the burner compartment door, exposing the burner
compartment.
2. Disconnect gas line and pilot tubing from gas valve so man-
ifold can be removed.
3. Disconnect wiring at gas valve. Be sure to note the proper
location of all electrical wiring before being disconnected.
Figure 36
Removing NOx inserts
25--40--03
4. Remove the four (4) screws holding the manifold and gas
valve to the manifold supports. Do not discard any screws.
See Figure 37.
5. Carefully remove the manifold assembly.
6. Removethe orifices fromthemanifoldandreplace them with
proper sized orifices. See Figure 38.
7. Tighten orifices so they are seated and gas--tight. See
Figure 38.
To Next Page
Loading...
