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7−Stack Temperature
Take a stack temperature reading in the vent connector pipe.
Subtract the room air temperature from the stack temperature.
This will give you the net stack temperature. Using efficiency
charts provided in most CO
2
analyzers you can tell at what ef
ficiency the furnace is operating.
V−DISASSEMBLY PROCEDURES
Use the following procedures to access and disassemble the
burner or blower if service to either is needed.
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at discon
nect switch(es). Unit may have multiple
power supplies.
A−Disassembling Burner
The burner assembly is attached to the vestibule panel by
three nuts. Slots are provided in the mounting flange for
removing the burner assembly from the vestibule. By
loosening the nuts and by turning the whole burner as
sembly counterclockwise (figure 29), the entire burner as
sembly will come out of the furnace. There is adequate wire
to remove the burner without disconnecting wires. Once re
moved, just turn the burner around in the vest panel area.
NOTE−Before disassembling any part of the burner, turn
off power and oil supply to the burner.
FIGURE 29
BURNER REMOVAL
First, loosen three nuts which
attach burner to vest panel.
Next, rotate burner counterclockwise
on slots then pull toward you.
nuts
1−Removing Ignition Transformer
1− Remove all four screws located on the side of the
ignition transformer. See figure 30.
2−
Lift the ignition transformer straight up.
Do
not hinge back. Porcelain isolators may break if
hinged back.
NOTE−When testing the solid state transformer, do not
use a transformer tester designed for iron magnet trans
formers. Damage to the tester may result
FIGURE 30
IGNITION TRANSFORMER
SCREWS
SCREWS
IGNITION
TRANSFORMER
ACCESS
DOOR
SCREW TO OPEN
ACCESS DOOR
2−Removing Cad Cell
1− Loosen the screw to the back access door until door
opens. See figures 30 and 31.
2− The cad cell will be located on the right side of the
chassis wall hung on a bracket. See figure 31.
3− Remove by loosening the screw on the bracket.
4− Disconnect the leads from the primary control termi
nal strip.
FIGURE 31
CAD CELL
ACCESS
DOOR
CAD CELL
SCREW
