15
441 01 5003 01
Specifications are subject to change without notice
8. Gas Supply and Piping
CARBON MONOXIDE POISONING, FIRE AND
EXPLOSION HAZARD.
Failure to follow this warning could result in
personal injury, death, and/or property damage.
Models designated for Natural Gas are to be used
with Natural Gas ONLY, unless properly converted to
use with Propane gas.
!
Gas Supply Requirements
•
Use only the Type of gas approved for this furnace. See rating
plate for approved gas type.
•
Gas input must not exceed the rated input shown on the rating
plate. Overfiring will result in failure of heat exchanger and
cause dangerous operation.
•
Do
NOT
allow minimum supply pressure to vary downward.
Doing so will decrease input to furnace. Refer to
Table 3
for
gas supply. Refer to
Table 7
or
Table 8
for manifold pressures.
Table 3
Gas Pressures
Gas Type
Supply Pressure in wc
Recommended
Max.
Min.
Natural
7
″
14
″
4.5
″
Propane
11
″
14
″
11
″
Natural to Propane Gas Conversion
Note: An accessory kit shall be used to convert to propane gas use,
see the furnace rating plate for the Propane conversion accessory
kit part number.
1. After disconnecting power and gas supply to the furnace,
remove the access door, exposing gas valve and burner
compartment.
2. Disconnect gas line from gas valve so manifold assembly
can be removed.
3. Disconnect wiring at gas valve. Be sure to note the proper
location of any and all electrical wiring disconnected.
4. Remove the four (4) screws holding the manifold and gas
valve to the manifold supports. Do Not discard any screws.
5. Carefully remove the manifold assembly.
6. Remove the Natural gas (brass) burner orifices from the
manifold assembly and replace them with the appropriate
Propane (silver) orifices furnished in the conversion kit
unless converting high altitude unit, then see
Table 6
or
Table 8
for appropriate orifices. (
Figure 10
)
Figure 10
Remove Orifices
25--21--00
7.
T
ighten the orifices so they are seated and gas tight about 1
1
/
8
″
from the face of the orifice to the back of the manifold
pipe (
Figure 11
). Make sure orifice is installed straight so that
it forms a right angle (90
°
) to the manifold.
Figure 11
Changing Orifices
Measure from face of orifice to
the back side of the manifold.
1.11
″
(28.2mm)
1.21
″
(30.8mm)
8. Remove the cap screw and pressure regulator adjusting
screw from valve. (see
Figure 12
)
9. Remove the existing regulator spring from the regulator
housing.
10. Insert the replacement spring (red color) contained in this kit
into regulator housing.
11. Install the pressure regulator adjusting screw and give it
eleven (11) full clockwise turns. This will set the manifold
pressure close to required setting for normal operation.
12. Replace the regulator cap screw.
13. Attach the Yellow Attention Label contained in the kit to the
Gas Valve where it can be readily seen.
Color Code For
Propane
Gas
Natural Gas
Pressure
Regulator
Adjusting Screw
Black
Black
Spring
Red
Stainless
Steel
Note: A low gas pressure switch is required for conversion.
Figure 12
Typical Regulator Assembly
