INSTALLATION MANUAL
HIGH EFFICIENCY
TUBULAR HEAT EXCHANGER SERIES
MODEL: AHV8*UH
(Two Stage Variable Speed Upflow / Horizontal / Low NOx)
57 - 120 MBH INPUT
(16.7 - 35.2 KW) INPUT
SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DUCTWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
GAS PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
ELECTRICAL POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Typical Attic Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Typical Suspended Furnace / Crawl Space Installation . . . . . . . . . . . . 7
Side Return Cutout Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Upflow Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Electrical Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Vent Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Unit Clearances to Combustibles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Minimum Duct Sizing For Proper Airflow . . . . . . . . . . . . . . . . . . . . . . . 5
Round Duct Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Cabinet and Duct Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Filter Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Ratings & Physical / Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Roof Pitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
SECTION I: SAFETY
This is a safety alert symbol. When you see this symbol on
labels or in manuals, be alert to the potential for personal
injury.
Understand and pay particular attention to the signal words DANGER,
WARNING, or CAUTION.
DANGER indicates an imminently hazardous situation, which, if not
avoided, will result in death or serious injury.
WARNING indicates a potentially hazardous situation, which, if not
avoided, could result in death or serious injury.
CAUTION indicates a potentially hazardous situation, which, if not
avoided may result in minor or moderate injury. It is also used to
alert against unsafe practices and hazards involving only property dam-
age.
LIST OF SECTIONS
VENT SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
SAFETY CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
START-UP AND ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . .20
WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
LIST OF FIGURES
Home Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Combustion Airflow Path Through The Furnace . . . . . . . . . . . . . . . . .17
Alternate Air Intake, Air Outlet and Chimney Connections . . . . . . . . .17
Air Inlet, Outlet and Chimney Connections . . . . . . . . . . . . . . . . . . . . .17
Typical Chimney Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Horizontal Air Inlet, Outlet and Chimney Connections . . . . . . . . . . . .18
Outside and Ambient Combustion Air . . . . . . . . . . . . . . . . . . . . . . . . .18
Pressure Switch Tubing Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Reading Gas Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
LIST OF TABLES
Estimated Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Unconfined Space Minimum Area in Square Inch . . . . . . . . . . . . . . .18
Air Flow Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Improper installation may create a condition where the operation of
the product could cause personal injury or property damage.
Improper installation, adjustment, alteration, service or mainte-
nance can cause injury or property damage. Refer to this manual
for assistance or for additional information, consult a qualified con-
tractor, installer or service agency.
This product must be installed in strict compliance with the installa-
tion instructions and any applicable local, state, and national codes
including, but not limited to building, electrical, and mechanical
codes.
EFFICIENCY
RATING
CERTIFIED
ISO 9001
Certified Quality
Management System
271001-UIM-A-0407