9
Mortex Products, Inc. / FT. WORTH, TX 76106
G17 / G18 Installation Instructions
Printed 04/04
8
Mortex Products, Inc. / FT. WORTH, TX 76106
G17 / G18 Installation Instructions
Printed 04/04
INSTALLATION INSTRUCTIONS
CUTTING ROOF JACK OPENING
A proper installation of the roof jack requires that openings
in roof and ceiling be on the same vertical centerline as the
furnace flue collar. See FIG. I
FIG. I - ROOF CUT-OUT
Mark the center point on the ceiling and scribe a 4” radius
(8” diameter) around this mark. If furnace is in place during
this step, cover the furnace and flue opening to prevent
debris from entering flue.
INSTALLING ROOF JACK
The roof jack body should be secured to the furnace before
the roof flashing is secured to the roof.
1. Insert roof jack body into opening in the roof.
2. From above, center the roof jack body aligning with
the furnace collar.
3. From inside the home, pull down 4-3/16” D flue
pipe seating the pipe fully and firmly over the
furnace flue collar.
4. Next pull down the 7” D combustion air pipe seating
it over the mating furnace collar. Rotate the
combustion air pipe lining up to the screw hole on the
7” furnace collar.
5. Check and make sure the combustion air pipe is fully
seated. Then drive a #10 sheet metal screw attaching
pipe firmly to furnace collar.
6. Install optional ceiling trim ring, 90-TRM-RNG
7. On the roof, caulk liberally under the roof jack
flashing.
8. Drive nails or screws through the flashing onto the
roof surface about 1- 1 _ inches apart. Caulk again
to ensure a leak tight joint.
9. Install roof jack crown and fasten to roof jack body
with three (3) screws (provided) using pre-punched
holes.
INSTALLATION IN SNOW REGIONS
When the combustion air inlet to the roof jack is blocked
with snow, the furnace will not operate properly due to the
depleted combustion air supply.
Therefore, if the furnace will be located in regions where
snow accumulation on the roof exceeds 7” or in H.U.D.
Snow Load Zones, a roof jack extension- Part No. 90-
0UTXT16-AL- is recommended.
ROOF JACK ON HI-PITCH ROOF
To install the RJS (3/12) Series Roof Jack on roofs which
have a slope between 4.5/12 - 6/12, install a Part No.
90-RJS56 Roof Saddle, Fig. J. The combined assembly of
the RJS Roof Jack and Roof Saddle will conform to the
higher roof pitch. If roof pitch is greater than 6/12, field
fabricate a suitable adapter, or consult with factory.
FIG. J - 90-RJS56 ROOF SADDLE, HI PITCH ROOF
TRANSIT ROOF JACK - MODE
RJF and RJS Roof Jacks feature a removable top crown. The
crown is normally installed at the factory. If road clearance
for the home requires that vent caps or crowns remain
uninstalled for road clearance, a Transit Mode Kit, Part No.
90-RJTRC is available. The kit, when used, allows for home
shipment with the crown shipped inside the home. The kit
includes a weather cap and four (4) warning tags.
FIG. K - 90-RJTRC TRANSIT MODE INSTALLATION
INSTALL TRANSIT ROOF JACK
AT MANUFACTURED HOME FACTORY
1. Roof Jack body (less crown) installed per instructions
in this manual.
2. Install weather cap from 90-RJTRC kit on RJF or RJS
upper body.
3. The 3 warning tags supplied must be attached as
follows:
• To homes gas line connection point
• To furnace gas control valve
• To furnace wall thermostat
4. Upper crown, in original carton must be stored in a
prominent location inside the home until crown
installation is made at site location.
AT MANUFACTURED HOME SITE
5. The transit weather cap is removed and
6. 90-RJCRWN-AL crown installed per these instructions.
See FIG K. Make sure crown engages RJ-body pipes
above the roof and crown is secured with 3 sheet
metal screws.
7. Transit system warning tags are discarded.
CONNECT POWER SUPPLY
1. Remove the furnace control panel cover.
2. Insert 115 V wiring through a strain relief bushing on
the left side of the furnace.
3. Connect the HOT wire to the BLACK pigtail lead;
connect the NEUTRAL wire to the WHITE pigtail lead.
Secure the connections with suitable wire nuts and
wrap with electrical tape. Refer to Pgs. 11 thru 13 and
one of the following Fig’s L,M,N,O,P or Q to select the
proper wiring diagram for connections
4. Connect the GROUND wire to a grounding screw in
the control panel.
5. Reinstall and secure the control panel cover
with screws.
WALL THERMOSTAT
The location of the wall thermostat is important, as it must
sense the desired temperature of the entire conditioned
space. Choose a location 4-5 feet above the floor,
preferably on an inside wall in an area with good air
circulation. Stay away from lamps and air registers and do
not install behind a door. Choose a location where the
temperature will be reasonably representative of other living
areas the thermostat is controlling.
CONNECT THERMOSTAT WIRES
When installing a furnace with a cooling coil compartment,
use of a five-conductor thermostat cable is recommended.
This will allow easy installation of an air conditioning sys-
tem at a later date.
1. Insert 24V wires through the small plastic bushing on
the left side of the furnace.
2. Connect low voltage wires to the color coded low
voltage pigtails at top of the control panel.
3. Connect low voltage wires to the wall thermostat.
NOTE: The use of 18-gauge wire is highly recommended to
carry the thermostat load. Use of smaller conductors risks
operational problems caused by loose or broken conductors
or wire that is too small to carry the load. Any such
problems are the responsibility of the installer.
With conductors smaller than 18 gauge, observe the
following guidelines.
Thermostat wire length
-furnace to thermostat-
Thermostat wire gauge
0-45 feet
22
0-70 feet
20
GAS PIPING
Supply piping must be sized in accordance with
recommendations found in National Fuel Gas Code ANSI
Z223.1/NFPA-54. In addition materials used in manufactured
homes must comply with requirements contained in HUD
Title 24, Section 3280.705 as well as A119.1 and A119.2
for recreational vehicles.
See chart in this manual for minimum sizes for NAT and LP
pipe and tubing serving the furnace only.
NOTE: The gas inlet on the gas control valve is 1/2-14NPT.
The gas line may be installed through the bottom casing or
on left or right side of furnace.
WARNING
Any attempt to operate furnace before replacing
transit-mode Weather Cap with Roof Jack Crown
may result in hazard of fire, explosion or
asphyxiation.
WARNING
To avoid electric shock, personal injury, or death,
turn off the power at the disconnect or the main
service panel before making any electrical
connections.
