How to Install a Gas Heater for a Garage

RON HAZELTON:

It’s chilly out here today. You know, this is my first winter here in this shop and already it’s become apparent that I’ve got to have some heat out here. Now, I don’t need to keep this at a constant temperature, that is, a living temperature, but I do want to be able to get the heat up quickly when I need it. So, I settled on this unit right here. It's called the hot dawg. Now this heater comes in 4 different sizes. 30,000 BTUs, 45,000 BTUs, 60,000 and 70,000 BTUs. This is the 60,000 BTU model right here and this is the one that's the right size for my shop. So let's get started. We're going to put this up. There we go. Now this heater is designed to attach directly to the bottom of the joist. But in this case, I want it mounted at an angle, so I've added a couple of 2 x 6's up here and lag screwed those into the joist.

Now since I'm going to be working alone today, one of the more challenging parts of this project may be hoisting this 80-pound heater up there where I'm going to attach it to those 2 x 6's. To start with, I've wrapped a couple of cargo straps around the case. A little research leads me to a marine supply store, where I check out things in the rigging department. Now, to do the heavy lifting today, I decided to use this marine block and tackle. It's designed to lift very heavy booms on sailing ships. Lightweight, very strong, a little pricey, but it's a lifetime tool. Now I'm going to attach it to this 2 x 4 that I put up earlier. The lower end of the block and tackle gets attached to the cargo straps. Then I hoist the 80-pound heater upward as easily as a sailor would raise a mainsail on the mizzenmast.

Once in position, I clamp the mounting flanges. And more clearance holes. Next, I insert carriage bolts - and finally twist on nuts and snug them tight with a socket wrench. Now this being a gas-burning appliance, I of course have got to exhaust those gases at a flue.

So the first thing I'm going to do is attach this T-shaped piece of flue to the back of the furnace right here. And I'll attach that permanently a little bit later on. Now there's going to be a second piece of pipe that will go from the center of this flue right up through the roof.

And that means we're going to have to cut a hole up there that's exactly on top of this one right here. So let's take a plumb bob. This is the best way to do this. I'm going to move it around up here until the plumb bob is centered directly over this flue.

Right, now I'll make a mark right up here at the top of the plumb bob line, right there. Next, I bore through the roof and insert a wire coat hanger. Well, the coat hanger marks the spot. We won't need that anymore. So let me push this back down through here.

Now what I want to do is draw a circle 6 inches in diameter - now this is a lumber crayon that I have in here - I bore a half-inch hole on the edge of the circle, insert the blade of the jigsaw and make the cutout. Well, this is the flashing that's going to make the watertight seal eventually around our flue.

I'm going to set this about where I want it here. And that is, I want to center the large opening down here on the bottom over that hole that we cut in the roof. That looks pretty good. Now I'm going to reach inside with my lumber crayon.

Be careful because this is sharp here - I'm going to trace the outline of this oval shaped base here. Then using a utility knife with a hooked blade, I cut along the mark that I just made. Next, I apply sealant to the lower shingles, where the base will be sitting on top.

Then I slide the flashing underneath the upper shingles and into the circular cutout. Finally, I secure the flashing base with roofing nails. This is double wall vent pipe. The inner liner's aluminum, the outside is galvanized steel.

Now the idea is that even though there are hot gases passing through this pipe, the outer jacket remains cool. So what I'm going to do is pass this up through that flashing we put on earlier. The lower end of the pipe I connect to the vent coming out of the back of the heater.

The joints are held together with couplings that snap into place. Back up on the roof, I slip a weather ring over the top of the vent and slide it down to the top of the flashing. Finally I set the vent cap in place and apply sealant to the nail heads.
With everything finished on the roof, I go back inside to make the electrical connections. Next I apply thread sealant to the gas pipe sections. Tighten them together and finally connect the flexible gas line. I installed the main part of the gas line and shut off valve earlier.

I've installed a programmable thermostat because out here in the garage workshop, I don't need heat all the time, just when I'm working. And the nice thing about this one is, if I'm coming to work at 9 o'clock, I can set this to bring the heat up around 8:30.

I can't tell you how glad I am that I put this unit in. In the few weeks since I've installed it, the temperature hasn't gotten above freezing and this heater has done a great job of giving me heat where I want it, when I want it.

Complete This One-person Installation of a Ceiling-mounted Vented Gas Heater in Your Garage or Workshop for Warmth on Demand

Select your garage gas heater by fuel type and BTU output appropriate for the environment. Our ceiling-mounted vented gas heater has an electric fan for circulation and a flue to vent fumes through the roof. A one-person project using block and tackle rigging to hoist the heater to a ceiling joist, it requires several trips to work from the roof.

Step 1

Attach Two-by-sixes across Joists for Diagonal/Corner Mounting of Gas Heater

Lag-screw two-by-sixes across ceiling joists to corner-mount the vented gas heater. These gas heaters are designed to hang from the ceiling joists, but aiming flow from the circulating fan diagonally across the garage will improve airflow in this situation.

securing the block and tackle rigging at the joists

Step 2

Lift the Gas Heater with Block and Tackle

Hook the upper end of a block and tackle to the beams and the lower end to cargo straps wrapped securely around the gas heater. Use the pulley to hoist the gas heater up to the joists and into position.

clamping the gas heater to a joist along its mounting flange

Step 3

Clamp the Heater to the Joists and Bore Clearance Holes

Position and temporarily clamp the heavy gas heater to the joists along its mounting flanges. Bore equally spaced clearance holes for carriage bolts in the ready-made cutouts along the mounting flanges.

hammering the carriage bolts to seat them in the wood

Step 4

Secure the Gas Heater to the Joists with Carriage Bolts

Insert a carriage bolt into each clearance hole and tap the head with a hammer to seat its collar in the wood. Twist on nuts and then finger-tighten and then snug them with a socket wrench. Remove the clamps.

marking flue position at the roof with a plumb bob

Step 5

Attach the T-shaped Flue and Mark Its Position at the Roof

Attach the T-shaped portion of the flue to the back of the gas heater. Use a plumb bob to determine the exact vertical position above the center of this flue pipe on the underside of the roof. Mark it.

cutting the flue opening through the roof

Step 6

Cut a Hole in the Roof for the Flue Pipe

Bore through the mark, inserting a wire to locate the hole on top of the roof. Outline the diameter of the flue, centered on the hole. On the outline, bore a pilot hole for a jigsaw and cut the opening.

cutting only the upper shingles along the mark

Step 7

Install the Funnel-shaped Flashing to Waterproof the Flue Opening

Center and mark the oval opening of the funnel-shaped flashing over the cutout. Cut away upper shingles along the mark. Apply sealant to the lower shingles and slide the flashing base under the upper shingles. Secure with roofing nails.

adding the weather ring to the vent pipe

Step 8

Install the Long Vent Pipe, Weather Ring, and Vent Cap

Insert the vent pipe through roof and flashing. Connect the lower end to the T-shaped flue, securing it with snap-in-place couplings. Add the weather ring and vent cap to the upper end of the pipe. Add sealant to nail heads.

Step 9

Make Required Electrical Connections for the Gas Heater

Remove the side panel from the gas heater housing to access the electrical components. Match wires and secure with wire nuts, following gas heater manufacturer's directions to make electrical connections for components such as the air circulation fan.

tightening the gas line connections with adjustable wrenches

Step 10

Connect the Rigid Gas Pipes and the Flexible Gas Line

Apply thread sealant to the gas pipe sections and screw them together. Snug the fittings with adjustable wrenches. Connect the flexible gas line and tighten the nut. The main gas line and shut off valve were installed before this project.