York 363857-YUM-A-0208 Input, Operating Instructions, Typical Flame Appearance, Filter Access

363857-YUM-A-0208

INPUT

The correct heat capacity of the furnace is regulated by the main burner orifices and the gas pressure. The proper ori- fices for natural gas are furnished but the gas pressure regu- lator must be adjusted by the installer or gas company service person.

OPERATING INSTRUCTIONS

TO SHUT DOWN THE FURNACE:

HEAT EXCHANGER TUBE

GAS

SUPPLY

PIPE

BURNER	BURNER FLAME
BURNER BRACKET	(BLUE ONLY)
IGNITOR

FIGURE 2 - TYPICAL FLAME APPEARANCE

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.Turn on the electric power supply.

4.Initiate a call for heat.

5.If the return air temperature is below the set point of the controller, the ventor fans will operate. After an adequate purge time, the intermittent ignition device will light the burners. The burners will extinguish and relight automati- cally upon the demand of the controller.

VENT SAFETY SYSTEM

EXHAUST VENT OUTLET

VENT FLUE ASSY.

COMBUSTION AIR INLET

SHIPPING LABELS (REMOVE SHIPPING LABELS PRIOR TO VENT INSTALLATION)

HEAT SECTION DOOR

Each gas furnace module is equipped with an automatic reset high temperature limit and rollout switch. In the unlikely event of a sustained main burner flame rollout, the switch will shut off the flow of gas by closing the main gas valve. The ignition module will also be disabled, preventing the flow of gas to the valve. The rollout switch for each module is located inside the gas heat section access door on the heat shield of each module. Flame rollout can be caused by blockage of the power vent system or improper gas pressure adjustment. If this occurs the furnace will not operate properly, 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 person. Refer to Figure 3 for a typical installation of vent hoods.

The ignition modules are designed such that if the furnace fails to ignite after 3 trials for ignition after a call for heat the flow of gas will be shut off and the ignition module will lock out for one hour. Then the modules will retry ignition and repeat cycle until ignition occurs, or call for heat is satisfied or power to unit is removed. If the furnace does not light after several tries, a service man should be called to determine the cause of the problem.

FIGURE 3 - FLUE VENT ASSEMBLY

This furnace is equipped with a blocked vented shut-off sys- tem (air proving switch). The purpose of the switch is to prove that there is combustion air being drawn through the heat section. The ignition control will not operate if this switch is not made in the pre-purge time of the vent assembly. In the event that the furnace fails to operate due to the pressure switch, a qualified service agency should be contacted.

Determine that external vent is in place (field installed) and clear and free of obstructions.

FILTER CHANNEL PERIMETER FRAME

	FILTERS
EXTERNAL
UPRIGHT	EXTERNAL
	UPRIGHT
FILTER
BRACKET	FILTERS

FILTER CHANNEL

BASE RAIL

FIGURE 4 - FILTER ACCESS

Johnson Controls Unitary Products 3