035-19992-001 Rev. A (0404)
USER’S INFORMATION,
MAINTENANCE AND
SERVICE MANUAL
MODELS: G8C/ GF8
(Single Stage Multi-Position)
EFFICIENCY
RATING
CERTIFIED
Thisproductwasmanufactured
inaplantwhosequalitysystem
iscertified/registeredasbeing
inconformitywithISO9001.
The manufacturer recommends that the user read all sec-
tions of this manual and keep the manual for future refer-
ence.
SECTION I: USER’S INFORMATION
SAFETY
1. The furnace area must be kept clear and free of combustible mate-
rials, gasoline and other flammable vapors and liquids.
2. Insulating materials may be combustible. The furnace must be
kept free and clear of insulating materials. The furnace area must
be examined when installed in an attic or other insulated space or
when insulation is added to be sure that the insulation material has
been kept away from the furnace.
3. The furnace needs air for combustion in order to operate properly
and safely. Do not block or obstruct air openings on the furnace,
air openings to the area where the furnace is installed, or spaces
around the furnace.
4. Follow the instructions exactly as shown on the OPERATING
INSTRUCTION LABEL or the Start-up and Shutdown Instructions
on Page 4 of this manual when lighting the furnace or turning the
furnace off.
5. Should the gas supply fail to shut off or if overheating occurs, shut
off the gas valve to the furnace before shutting off the electrical
supply.
6. Do not use this furnace if any part has been under water. A flood-
damaged furnace is extremely dangerous. Attempts to use the fur-
nace can result in fire or explosion. A qualified service agency
should be contacted to inspect the furnace and replace all gas
controls, control system parts, electrical parts that have been wet
or the furnace if deemed necessary.
FIRE OR EXPLOSION HAZARD - Failure to follow safety
warnings exactly could result in serious injury, death, or prop-
erty damage.
— Do not store or use gasoline or other flammable
vapors and liquids in the vicinity of this or any other
appliance.
— WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone
(including cell phone) in your building.
• Leave the building immediately.
• Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire depart-
ment.
— Installation and service must be performed by a quali-
fied installer, service agency or the gas supplier.
CONTACT INFORMATION
• Go to website at www.york.com click on “contact”, then click on “contact form” and follow the instructions.
• Contact us by mail:
York International
Consumer Relations
5005 York Drive
Norman, OK 73069
TABLE OF CONTENTS
CONTACT INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
USER’S INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION (50-125 MBH INPUT MODELS) . . . . . . . . . . . . . . .2
DESCRIPTION (150 MBH INPUT MODELS) . . . . . . . . . . . . . . . . . . 2
INSTRUCTIONS FOR EXAMINING THE FURNACE
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
HOW YOUR GAS FURNACE WORKS . . . . . . . . . . . . . . . . . . . . . . 4
START-UP AND SHUTDOWN INSTRUCTIONS . . . . . . . . . . . . . . . 4
Read the Instructions Below Before Trying to Start the Furnace . . 4
Operating Instructions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
To Turn Off the Appliance: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
FURNACE USER MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . 4
Air Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Removing Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Blower Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Motor Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
SERVICE AND MAINTENANCE MANUAL . . . . . . . . . . . . . . . . . . . . 6
SAFETY SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
FURNACE MAINTENANCE SECTION . . . . . . . . . . . . . . . . . . . . . . .6
FURNACE CLEANING SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Burner Removal/Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Cleaning the Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
SEQUENCE OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Continuous Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Intermittent Blower - Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Heating Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Hot Surface Ignition System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
FURNACE CONTROL DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . .8
REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
FIELD INSTALLED ACCESSORIES - NON-ELECTRICAL . . . . . .11
REPLACEMENT PART CONTACT INFORMATION . . . . . . . . . . . . .11
WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
LIMITED WARRANTY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16