66832-UIM-D-1205
EFFICIENCY
RATING
CERTIFIED
ISO 9001
Certified Quality
Management System
HIGH EFFICIENCY
CLAM TUBE HEAT EXCHANGER SERIES
MODELS: G8C/GF8
(Single Stage Multi-Position)
50 - 150 MBH INPUT
(14.65 - 44.00 KW) INPUT
INSTALLATION MANUAL
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.
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.
TABLE OF CONTENTS
SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DUCTWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
GAS PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
ELECTRICAL POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
ACCESSORY CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
TWINNING AND STAGING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
VENT/COMBUSTION AIR SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . .16
SAFETY CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
START-UP AND ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . .22
LIST OF FIGURES
Upflow/Horizontal Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Downflow/Horizontal Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Vent Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Top Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Combustible Floor Base Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Typical Attic Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Typical Suspended Furnace / Crawl Space Installation . . . . . . . . . . . . 9
Side Return Cutout Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Horizontal Mount and Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Downflow Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Return Filter Grill and Return Duct Installation . . . . . . . . . . . . . . . . . . 11
Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Upflow Configuration (50-125 MBH Model Only) . . . . . . . . . . . . . . . . 12
Downflow Configuration (50-125 MBH Model Only) . . . . . . . . . . . . . 12
Upflow/Horizontal Configuration (150 MBH Model Only) . . . . . . . . . . 12
Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Electrical Wiring - Upflow Position . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Line Wiring Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Two-Stage Heating and Cooling Thermostat Connections . . . . . . . . 14
Accessory Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Typical Twinned Furnace Application . . . . . . . . . . . . . . . . . . . . . . . . .15
Single Stage Twinning Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . .15
Two-Stage Twinning Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . .16
Vent Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Vent Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Alternate Air Intake, Air Outlet and Chimney Connections . . . . . . . . .17
Air Inlet, Outlet and Chimney Connections . . . . . . . . . . . . . . . . . . . . .17
Typical Sidewall Vent Application . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Typical Sidewall Vent and Termination Configuration . . . . . . . . . . . .18
Typical Chimney Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Horizontal Air Inlet, Outlet and Chimney Connections . . . . . . . . . . . .18
Home Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Combustion Airflow Path Through The Furnace
Casing to the Burner Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Outside and Ambient Combustion Air . . . . . . . . . . . . . . . . . . . . . . . . .21
Pressure Switch Tubing Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Reading Gas Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Typical Heat/Cool Speed Tap Connections . . . . . . . . . . . . . . . . . . . .26
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
LIST OF TABLES
Unit Clearances to Combustibles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Minimum Duct Sizing For Proper Airflow . . . . . . . . . . . . . . . . . . . . . . . 6
External Static Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Cabinet and Duct Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Filter Sizes - Upflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
High Altitude Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Ratings & Physical / Electrical Data - Upflow Models . . . . . . . . . . . . 13
Roof Pitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Horizontal Sidewall Venting Clearances . . . . . . . . . . . . . . . . . . . . . . .18
Estimated Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Unconfined Space Minimum Area in Square Feet . . . . . . . . . . . . . . .20
Field Installed Accessories - Non Electrical . . . . . . . . . . . . . . . . . . . .23
Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Nominal Manifold Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Filter Performance - Pressure Drop Inches W.C. and (kPa) . . . . . . . .26
Blower Performance - CFM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
