Input; Operating Instructions; To Shut Down The Furnace; To Light The Furnace - York DF078 Series User's, Maintenance And Service Information Manual

035-19047-002-A-1103

INPUT

The correct heat capacity of the furnace is regulated by
the burner orifices and the gas pressure. The proper
orifices are furnished but the gas pressure regulator
must be adjusted by the installer or gas utility service
technician.

OPERATING INSTRUCTIONS

TO SHUT DOWN THE FURNACE:

1. Close the main gas shutoff valve(s).
2. Turn off the electric power supply.

TO LIGHT THE FURNACE:

1. Do not attempt to light manually.
2. Open the main gas shutoff valve(s).
3. Adjust the set point of the room thermostat above
the temperature in the space.
4. Turn on the electric power supply.
5. The draft fan will operate. After an adequate purge
time, the electric spark igniter will light the burners.
6. The burners will extinguish and relight automati-
cally upon the demand of the room thermostat.

VENT SAFETY SYSTEM:

This gas furnace is equipped with a manual reset high
temperature sensor or rollout switch which in the
unlikely event of a sustained main burner flame rollout
will shut off the flow of gas by closing the main gas
valve. The ignition modules will also be disabled, pre-
venting the flow of gas to the valve. The switch is
located inside the gas heat access panel above the
burner inlet. Flame rollout can be caused by blockage
of the power vent system, improper gas pressure or
adjustment. If this event occurs the furnace will not
operate properly. The gas supply to the furnace should
be shut off and no attempt should be made to place the
furnace in operation. The system should be inspected
by a qualified service technician. Refer to Figure 2 for a
typical installation.

100% SHUT OFF:

The ignition modules are designed for 100% shut-off. If
the furnace fails to ignite after three ignition attempts,
the flow of gas will be shut off and the ignition module
will lock out. The module can be reset by:
A. Turning the system switch on the room thermostat
to the "OFF" position and back to the "HEAT" posi-
tion.
B. Decreasing the set point of the room thermostat
below the temperature in the conditioned space
and returning it to its original setting.
Unitary Products Group
C. Opening and closing the unit's main disconnect
switch.
FIGURE 2- TYPICAL INSTALLATION
If the furnace continues to lock out, a qualified service
technician should be called to determine the cause of
the problem.
ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow safety warnings exactly could result
in dangerous operation, serious injury, death or prop-
erty damage.
Improper servicing could result in dangerous opera-
tion, serious injury, death or property damage.
• Before servicing, disconnect all electrical power
to furnace.
• When servicing controls, label all wires prior to
disconnecting. Reconnect wires correctly.
• Verify proper operation after servicing.
Prior to any of the following maintenance procedures,
shut off all power to the unit to avoid personal injury.
M a i n G a s
S h u t - o f f V a l v e
. i e l d I n s t a l l e d
( M o u n t e d E x t e r n a l l y )
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