34
440 01 2020 01
T
S
H
J
1”
2”
N
M
K
R
P
L
2”
25--20--46b
Plenum
Figure 38
Coil Cabinet Subbase
A
A = 4
1
/
4
” Minimum clearance from back of hole to wall or other
obstruction.
Hole in
Floor
25--20--46a
Furnace
Wood Screw
Plenum
Wood Floor
Insulation of
Combustible
Floor Base
Figure 39
Setting the Subbase
This subbase for combustible floors has been designed so that the
height of the subbase raises the downflow coil off the floor to allow
easy installation of the condensate drain. See
Figure 40
.
Condensate Line Raised by Base
Figure 40
25--20--52
8. Checks and Adjustments
FIRE OR EXPLOSION HAZARD.
Failure to turn OFF gas at shut off before connecting
manometer can result in death, personal injury and/or
property damage.
Turn OFF gas at shut off before connecting manometer.
!
Startup
NOTE:
Refer to the start--up procedures in the “
User’s Information
Manual
” or to the “
Operating Instructions Label
” on the furnace.
!
If any sparks, odors or unusual noises occur,
immediately shut OFF power to furnace. Check for
wiring errors or obstruction to blower.
Failure to correct hazard could result in death,
personal injury, and/or property damage.
CAUTION
Gas Supply Pressure
Gas supply pressure should be within minimum and maximum val-
ues listed on rating plate. Pressures are usually set by gas suppli-
ers.
Manifold Gas Pressure Adjustment
NOTE:
Make adjustment to manifold pressure with burners operat-
ing.
1. Remove the burner compartment door.
2. With gas
OFF
, connect manometer to tapped opening on
gas valve. Use manometer with a 0 to 15
²
water column
range.
3. Turn gas
ON
and remove adjustment screw cover on gas
valve. Turn counterclockwise to decrease pressure and
clockwise to increase.
4. For altitudes up to 2000
¢
, set pressure to value shown in
Table 5
,
±
0.3
²
(8mm) water column. For altitudes of 2000
¢
to
8000
¢
, see Section 5 for correct pressure setting.
Adjust Pilot Burner
The furnace has a pilot flame to light the main burner. The flame
should surround
3
/
8
²
to
1
/
2
²
of the flame sensor. See
Figure 41.
To
adjust, remove cap from pilot adjusting screw on gas valve. Turn
screw counterclockwise to increase or clockwise to decrease
flame as required. Replace adjusting screw cap.
Summary of Contents for 9MPT050F12A
Page 46: ...46 440 01 2020 01...
