INSTALLATION INSTRUCTIONS
Gas Furnace: (F/G)9MVT, (F/G)9MXT, (F/G)9MXE
440 01 4001 05
29
Specifications subject to change without notice.
Figure 33
Gas Valves
Redundant Automatic Gas Valve (Two
−
Stage)
ON/OFF Switch
Regulator Seal Cap
Regulator Adjustment
Regulator Seal Cap under Cap
1/2” NPT Outlet
1/8” NPT Manifold
Pressure Tap
1/8” NPT Inlet
Pressure Tap
1/2” NPT Inlet
A11152
Redundant Gas Valve (Single Stage)
ON/OFF Switch
Regulator Seal Cap
Regulator Adjustment
Regulator Seal Cap under Cap
1/2” NPT Outlet
1/8” NPT Manifold
Pressure Tap
1/8” NPT Inlet
Pressure Tap
1/2” NPT Inlet
A11153
If pressure exceeds 0.5 psig (14
−
in. w.c.), gas supply pipe must
be
disconnected from furnace and capped before and during
supply
pipe pressure test. If test pressure is equal to or less
than 0.5 psig
(14
−
in. w.c.), turn off electric shutoff switch
located on furnace gas control valve and accessible manual
equipment shutoff valve before and during supply pipe
pressure test. After all connections have been made, purge
lines and check for leakage at furnace prior to operating
furnace.
The gas supply pressure shall be within the maximum and
minimum inlet supply pressures marked on the rating plate with
the furnace burners ON and OFF.
Some installations require gas entry on right side of furnace (as
viewed in upflow). (See
Figure 34
)
Gas Pipe Grommet
For direct vent (2-pipe) applications, the knockout for the gas
pipe must be sealed to prevent air leakage. Remove the
knockout, install the grommet in the knockout, then insert the
gas pipe. The grommet is included in the loose parts bag. (See
Figure 34
)
Figure 34
Gas Entry
Gas Pipe Grommet Required
For Direct Vent Applications
Left Side Gas Entry. Gas Pipe
Grommet Required For Direct
Vent Applications.
A11338
ELECTRICAL CONNECTIONS
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
Blower door switch opens 115
−
v power to control. No
component operation can occur. Do not bypass or close
switch with blower door removed.
See
Figure 35
for field wiring diagram showing typical field
115
−
v wiring. Check all factory and field electrical connections
for tightness.
Field
−
supplied wiring shall conform with the limitations of 63
°
F
(33
°
C) rise.
WARNING
!
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, or property damage.
The cabinet MUST have an uninterrupted or unbroken
ground according to NEC ANSI/NFPA 70
−
2011 or local
codes to minimize personal injury if an electrical fault
should occur. In Canada, refer to Canadian Electrical
Code CSA C22.1. This may consist of electrical wire,
conduit approved for electrical ground or a listed,
grounded power cord (where permitted by local code)
when installed in accordance with existing electrical
codes. Refer to the power cord manufacturer’s ratings
for proper wire gauge.
Do not use gas piping as an electrical ground.
CAUTION
!
FURNACE MAY NOT OPERATE HAZARD
Failure to follow this caution may result in intermittent
furnace operation.
Furnace control must be grounded for proper operation
or else control will lock out. Control must remain
grounded through green/yellow wire routed to gas
valve and manifold bracket screw.
