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269425-UUM-A-0407

USER’S INFORMATION,

MAINTENANCE AND 

SERVICE MANUAL

HIGH EFFICIENCY
TUBULAR HEAT EXCHANGER SERIES

MODEL: AHS8*UH 
(Single Stage Upflow / Horizontal / Low NOx)

EFFICIENCY
RATING
CERTIFIED

ISO 9001

Certified Quality

Management System

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 3 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
INSTRUCTIONS FOR EXAMINING THE 
FURNACE INSTALLATION   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
HOW YOUR GAS FURNACE WORKS   . . . . . . . . . . . . . . . . . . . . . . 3
START-UP AND SHUTDOWN INSTRUCTIONS  . . . . . . . . . . . . . . . 3

Read the Instructions Below Before Trying to Start the Furnace . . 3
Operating Instructions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
To Turn Off the Appliance: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

FURNACE USER MAINTENANCE   . . . . . . . . . . . . . . . . . . . . . . . . . 4

Air Filters  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Removing Filters  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Blower Care  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Motor Lubrication  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

SERVICE AND MAINTENANCE MANUAL   . . . . . . . . . . . . . . . . . . . . 5

SAFETY SECTION  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
FURNACE MAINTENANCE SECTION  . . . . . . . . . . . . . . . . . . . . . . .5
FURNACE CLEANING SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Burner Removal/Cleaning   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Cleaning the Heat Exchanger   . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

SEQUENCE OF OPERATION   . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Continuous Blower  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Intermittent Blower - Cooling   . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Heating Cycle  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Hot Surface Ignition System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

TROUBLESHOOTING   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
FURNACE CONTROL DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . .7
DIAGNOSTIC FAULT CODE STORAGE AND RETRIEVAL   . . . . . .8

REPLACEMENT PARTS LIST   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
REPLACEMENT PART CONTACT INFORMATION . . . . . . . . . . . . .10
WIRING DIAGRAM   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Summary of Contents for AHS8 UH Series

Page 1: ...ystem 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...

Page 2: ...nate outside the space containing the furnace 4 Examine the furnace casing making sure the physical support is sound without sagging cracks or gaps Examine the furnace base making sure it is physicall...

Page 3: ...TOP Read the safety information above 2 Set the thermostat to the lowest setting 3 Turn off all electric power to the appliance 4 Remove furnace door 5 Move gas control switch to the OFF position Do n...

Page 4: ...s with the same size new filter s Throw away filter s may be replaced with cleanable filter s at this time Cleanable filter s may be cleaned as described in the manufacturer instructions or as descri...

Page 5: ...g the burner assembly to the vestibule panel and remove this assembly Handle the assembly carefully since it contains the igniter which is fragile and easily broken The lower portion of the heat excha...

Page 6: ...y jumper located on the control board See Figure 8 The heating cycle is complete and ready for the start of the next heating cycle If the flame is not detected within 7 seconds of the gas valve openin...

Page 7: ...wer motor 5 RED FLASHES This fault is indicated if the normally closed contacts in the rollout switch opens The rollout control is manually reset If it has opened check for proper combustion air prope...

Page 8: ...retrieve the error codes push the LAST ERROR button The LED on the control will then flash the error codes that are in memory starting with the most recent There will be a two second pause between eac...

Page 9: ...MBH 1SR0302 SIDE RETURN FILTER KIT 1 FILTER ALL MODELS 1SR0200 SIDE RETURN FILTER KIT 1 4 FILTER ALL MODELS 1BR0114 BOTTOM RETURN FILTER KIT 1 FILTER 14 1 2 CABINETS 1BR0214 BOTTOM RETURN FILTER KIT 1...

Page 10: ...E BURNER Natural 45 38 PLATE RESTRICTOR 39 COLLAR FLUE 40 LO NOX SCREEN L Models Only MISCELLANEOUS 41 42 SIGHT GLASS OVAL 43 GASKET RESTRICTOR PLATE 44 TUBING SILICONE 45 SHIELD INDUCER 46 WIRING DIA...

Page 11: ...269425 UUM A 0407 Unitary Products Group 11 SECTION IV WIRING DIAGRAM FIGURE 9 Wiring Diagram...

Page 12: ...ts installed in the United States and Canada EXCLUSIONS This warranty does not cover any 1 Shipping labor or material charges 2 Damages resulting from transportation installation or servicing 3 Damage...

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