MORTEXPRODUCTSINC 501TERMINALRDFORTWORTH,TX76106 Page1
INSTALLATION MANUAL
DOWNFLOW ONLY GAS FURNACE
SIZES 60, 70, 77, 90
MODELS: G18D SERIES CATEGORY I MOBILE HOME GAS FURNACE
LIST OF SECTIONS
1 – Safety 1 6 – Combustion Air and Vent System 19
2 – General Information 5 7 – Furnace Startup, Diagnostics and Sequence of Operation 27
3 – Furnace Duct connections and Duct System 8 8- Blower Performance 32
4 – Gas Supply and Valve Connections 10 9 – Wiring Diagrams 33
5 – Line and Low Voltage Wiring 14
LIST OF FIGURES
1 - Furnace Dimensions 7 18 – Typical Single Stage Heat / Cool Digital T’stat 2 Stage Furnace 18
2 – Duct Connector Dimensions 8 19 – Typical 2 Stage Heating/Cooling Digital T’stat Connections 18
3 – Duct Connector and Floor Base Installation 8 20 – Roof Jack Mounting Collars – Top of Furnace 20
4 – Air Distribution System – Single Trunk Duct 9 21 – Roof Jack Indoor Extension Pipes 20
5 – Air Distribution System – Double Trunk Duct 9 22 – Roof Jack Outdoor Extension Pipes 20
6 – Air Distribution Systems – Graduated trunk duct 9 23 – Roof Jack Assembly (Slope Saddle) 21
7 – Furnace Base Openings, Fuel, Electric & A/C Line Penetrations 9 24 – Roof Jack Crown Assembly 21
8 – Duct Connector Depths 9 25 – Combustion Air Path thru the Roof Jack & Thru the Pipes 22
9 - Outdoor Fresh Air Intake Knockout 10 26 –
Outside Ambient Combustion Air Openings and Ducts 23
10 – White Rodgers 36J29 Gas valve 11 27 – Home Layout and Vent Clearances 24
11 – Supply Gas Piping 11 28 – Outside Combustion Air and Vent Safety Check Procedure 25
12- Furnace Component Locations 16 29 – Typical Roof Jack Installation 26
13 – Separate T’stat, Furnace & Cooling Unit WD 17 30 – Reading the Inlet (Supply) Gas Pressure (INP) 29
14 – Separate T’stat, furnace, Cooling Unit & Trans W.D. 17 31 – Reading the Outlet (Manifold) Gas Pressure 29
15 – Same T’stat, Separate Furnace, Cooling Unit & Trans W.D. 17 32 – Integrated Control Board 30
16 – Same T’stat Separate Furnace, Heat Pump and Transformers 18 33 – Wiring Diagram A/C Ready Furnace 33
17 – Same T’stats Separate Furnace, Cooling Unit and Transformers 18 34 - Wiring Diagram Heating Only 34
LIST OF TABLES
1 – Furnace Clearances to Combustibles 6 10 – Recommended Thermostat Wire Colors & Connections 19
2 – Model Nomenclature 7 11 – Estimated Free Area 22
3 – High Altitude Gas Orifice Chart 13 12 – Vent Clearances 24
4 – Gas Pipe Capabilities 14 13 – Roof Jack Specifications 26
5 – Ratings and Physical Electrical Data 14 14 – Input Calculations for a cu-ft Gas Meter 28
6 – Heating Only Models 1/3 HP Blower and Motor Rating 15 15 – Input calculations for a Mj/m³ Gas Meter 28
7 – A/C Ready Models 1/3 HP Blower & Motor Rating 15 16 – Inlet (Supply) Gas Pressure Range 29
8 – A/C Ready Models 3/4 HP Blower & Motor Rating 15 17 – Blower Performance 32
9 – Low Voltage, Wire Gage and Max Lengths 16
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
property damage.
SAVETHISMANUALFORFUTUREREFERENCE
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