MGD Series Gas Furnace
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. 1
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, canter the roof jack body aligning with the furnace collar.
3.From inside the home, pull down
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” 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,
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 – 11/2” 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
Installation Instructions
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 – Part5 No. 90-
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.
Heat Controller, Inc. Jackson, MI 49203 | MGD Installation Instructions 8 |
