1
Mortex Products, Inc. / FT. WORTH, TX 76106
G17 / G18 Installation Instructions
Printed 04/04
16
Mortex Products, Inc. / FT. WORTH, TX 76106
G17 / G18 Installation Instructions
Printed 04/04
SEALED COMBUSTION
DOWNFLOW
GAS FURNACE
FOR INSTALLATION IN:
MANUFACTURED (MOBILE) HOMES,
RECREATIONAL VEHICLES, PARK MODELS, MODULAR HOMES AND
BUILDINGS
CAUTION: READ ALL SAFETY GUIDES
BEFORE INSTALLING THIS FURNACE
Contents
Page
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Installation Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
High Altitude Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Installation Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Return Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5
Alcove & Closet Installations . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Air Distribution Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Duct Connector/Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Install Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Roof Jack Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Cut Openings & Install Roof Jack . . . . . . . . . . . . . . . . . . . . . . . .8
Installing in Snow Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Roof Jack On Hi-Pitch Roof . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Transit-mode Roof Jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-9
Connect Power Supply Wires . . . . . . . . . . . . . . . . . . . . . . . . . .9
Wall Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Connect Thermostat Wires . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-10
Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-13
Repair Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-15
Final Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Furnace and Air Conditioner Installations . . . . . . . . . . . . . . . . .16
High Altitude Deration Chart . . . . . . . . . . . . . . . . . . . . . . . . . .16
GENERAL INFORMATION
These downflow sealed combustion furnaces install in
Manufactured Homes, Recreational Vehicles or modular
construction. The furnaces conform to Part 3280 (a) (2) of HUD
Manufactured Home Construction and Safety Standards. They
must be installed only with listed RJ-Roof Jack, sealed
combustion venting system.
NOTE: These instructions are intended to assist qualified
individuals experienced in the installation of heating equipment.
Some state and local codes require installation personnel to be
licensed. Read all instructions before starting the installation.
SAVE THIS MANUAL
NOTICE
- A furnace set-up and any adjustment needed is the
responsibility of the installer/retailer/contractor and is not
covered by the furnace manufacturers warranty.
CHECKLIST: FURNACE START-UP
1. Has furnace roof jack crown been correctly installed?
2. Has the furnace gas valve and burner orifice been correctly
converted to L.P. Gas where applicable?
3. Is the gas line outlet pressure set for the fuel used?
NAT Gas is 3.5” W.C. and L.P. Gas is 10.0”W.C.
4. If the home uses a crossover air connector duct, is it installed
per the homebuilders installation instruction?
5. Has the furnace been operated through a complete
heating cycle?
INSTALLATION INSTRUCTIONS
FINAL PROCEDURE
INSTALL FURNACE DOOR PANELS
A. Install the lower door panel by engaging 2 tabs on
bottom cabinet pan into slots on plastic end cap. Then,
push in top of door panel until clips on the center divider
panel are engaged with latches on door.
B. Install the upper louver door panel in a similar manner,
by first engaging tabs on the center divider and then
pushing the panel in to engage the clips at top of the
cabinet.
FINISH AND TRIM
The alcove or closet installation may be finished and
trimmed out as needed.
AIR CONDITIONING SYSTEMS
If an air conditioning system is installed which does not use
the blower for air distribution and operates completely
independent of the furnace, the thermostat system shall
include interlock, which prevents simultaneous operation of
the furnace and air conditioner. An interlock system
typically contains a switch, which must be turned to either
HEAT or COOL to activate either heating or cooling
operation. A cooling thermostat may include a positive OFF
switch for this purpose.
When used in connection with a cooling unit the furnace
shall be installed parallel with or on the upstream side of
the cooling unit to avoid condensation in the heat
exchanger. For installations with a parallel flow
arrangement, the furnace must be equipped with a damper
or other means to prevent cold air from being discharged
up around the heat exchanger.
GAS VALVE CONVERSION INSTRUCTIONS
1. Follow instructions “TO TURN OFF GAS TO APPLIANCE”
2. Remove two bolts securing the gas valve bracket. Pull gas valve
valve bracket and burner orifice holder exposing the main burner orifice.
3. Install burner orifice specified on the rating plate for the desired gas.
Conversion parts are in a bag attached to the gas valve.
4. Replace valve, bracket/orifice holder, and bolts.
Attach ID tag for the desired gas adjacent to the gas valve.
Ensure that all connections are tight.
5. Unscrew and reverse the pressure regulating cap so the name of the
desired gas is closest to the valve. See illustration.
HIGH ALTITUDE DERATE CHART- MAIN BURNER ORIFICE SIZE
NATURAL GAS
ELEVATION
60,000 BTUH FURNACE
70,000 BTUH FURNACE
75,000 BTUH FURNACE
90,000 BTUH FURNACE
PART NO
ORIF DIA. DRILL SIZE
PART NO
ORIF DIA. DRILL SIZE
PART NO
ORIF DIA. DRILL SIZE
PART NO
ORIF DIA.
DRILL SIZE
SEA LEVEL
72AG-147
0.1470
26
72AG-159
0.1590
21
72AG-161
0.1610
20
72AG-180
0.1800
15
2,000
72AG-144
0.1440
27
72AG-154
0.1540
23
72AG-161
0.1610
20
72AG-177
0.1770
16
3,000
72AG-140
0.1405
28
72AG-154
0.1540
23
72AG-159
0.1590
21
72AG-173
0.1730
17
4,000
72AG-140
0.1405
28
72AG-152
0.1520
24
72AG-157
0.1570
22
72AG-173
0.1730
17
5,000
72AG-140
0.1405
28
72AG-149
0.1495
25
72AG-154
0.1540
23
72AG-169
0.1690
18
6,000
72AG-136
0.1360
29
72AG-147
0.1470
26
72AG-152
0.1520
24
72AG-166
0.1660
19
7,000
72AG-136
0.1360
29
72AG-144
0.1440
27
72AG-149
0.1490
25
72AG-161
0.1610
20
8,000
72AG-128
0.1285
30
72AG-140
0.1405
28
72AG-147
0.1470
26
72AG-161
0.1610
20
9,000
72AG-128
0.1285
30
72AG-140
0.1405
28
72AG-144
0.1440
27
72AG-157
0.1570
22
10,000
72AG-128
0.1285
30
72AG-136
0.1360
29
72AG-140
0.1405
28
72AG-152
0.1520
24
LP-PROPANE GAS
ELEVATION
60,000 BTUH FURNACE
70,000 BTUH FURNACE
75,000 BTUH FURNACE
90,000 BTUH FURNACE
PART NO
ORIF DIA. DRILL SIZE
PART NO
ORIF DIA. DRILL SIZE
PART NO
ORIF DIA. DRILL SIZE
PART NO
ORIF DIA.
DRILL SIZE
SEA LEVEL
72AG-089
0.0890
43
72AG-099
0.0995
39
72AG-101
0.1015
38
72AG-113
0.1130
33
2,000
72AG-086
0.0860
44
72AG-098
0.0980
40
72AG-099
0.0995
39
72AG-110
0.1100
35
3,000
72AG-086
0.0860
44
72AG-096
0.0960
41
72AG-098
0.0980
40
72AG-110
0.1100
35
4,000
72AG-086
0.0860
44
72AG-096
0.0960
41
72AG-096
0.0960
41
72AG-106
0.1065
36
5,000
72AG-082
0.0820
45
72AG-093
0.0930
42
72AG-096
0.0960
41
72AG-106
0.1065
36
6,000
72AG-082
0.0820
45
72AG-093
0.0930
42
72AG-093
0.0930
42
72AG-104
0.1040
37
7,000
72AG-081
0.0810
46
72AG-089
0.0890
43
72AG-093
0.0930
42
72AG-101
0.1015
38
8,000
72AG-078
0.0780
47
72AG-089
0.0890
43
72AG-089
0.0890
43
72AG-101
0.1015
38
9,000
72AG-078
0.0780
47
72AG-086
0.0860
44
72AG-089
0.0890
43
72AG-098
0.0980
40
10,000
72AG-076
0.0760
48
72AG-086
0.0860
44
72AG-086
0.0860
44
72AG-096
0.0960
41
Reference: NFPA No. 54, ANSI Z 223.1 National Fuel Gas Code
Table shows 4% Input Reduction per 1,000 feet elevation.
For Canadian High Altitude (2,000-4,500 feet), reduce gas pressure to burner manifold (manifold Ps.) to 3.0" W.C., and 9.0" W.C. for LP (Propane) Gas
G17D, G18D
Sizes 060-090
WARNING-RISK OF FIRE OF ELECTRICAL SHOCK
Only qualified service personnel shall be used to install
and provide maintenance of this furnace.
P/N: 61GF0011
