How To: Replace a Gas Water Heater
Ben Goheen, a master plumber of over 15 years, has all the pro tips you need to properly replace your gas water heater and thermal expansion tank. Follow as he explains how to safely and efficiently complete the job with SharkBite Max, Eastman and HoldRite products.
First, assess your current gas water heater by looking for leaks. Check the age of your heater, and if it’s over 10 years old, consider replacing it. After you know what to improve in your water heater setup, you’re ready to remove the old unit.
Remove the Old Water Heater
Before starting this project, here is the list of tools you’ll need to remove your water heater.
- Copper cutters
- Tongue and groove pliers
- Screwdriver
- Razor blade (for the vent tape)
- Nut driver
- Pipe dope
- Teflon tape
- CPVC cutters
- Nut driver
1. Shut off water
Once you have all your tools, shut off the gas valve and cold water valve. The cold water valve is separate from the main water shut-off and is located on the cold line of your water heater.
Read More: How to Turn Off Main Water Valve for Plumbing Repairs
2. Measure home water pressure
Next, measure your home water pressure with a pressure gauge that goes up to 200 psi. This can be tested anywhere after the pressure regulating valve, which includes your back spigot, laundry box and water heater.
To test it on the water heater, screw the gauge onto the boiler drain and turn the cold-water valve back on. Then, open the valve on the drain to get the psi reading, which should be between 50-70 psi. Keep this pressure in mind for when it’s time to install the new thermal expansion tank.
3. Drain the water heater
After measuring your home pressure, drain your heater with a water hose. Attach it to the boiler drain and open the valve on the drain, then shut the cold-water valve off and break the vacuum on your T&P valve. While it’s still draining, turn the main water line off and the cold water valve back on. This will drain the water left in your pipes into the water heater, with no added pressure going to the expansion tank.
4. Disconnect draft hood and gas line
Then, use the nut driver and razor blade to disconnect the vent from the draft hood. The vent needs to be secured with at least three screws, so keep this in mind when it’s time to install your new heater.
Now you can disconnect the gas line. First, check that your gas valve is shut off, then use your pliers to disconnect the line completely. You will smell some gas, but it should subside quickly. Once the line is removed from the valve and sediment trap, disconnect the trap and set it aside to use later. The sediment trap protects the gas control valve from debris, so this is essential for installing a new water heater.
5. Disconnect water lines and expansion tank
Once the gas line is disconnected, you can cut out the relief line and hot and cold water lines. To disconnect the relief line, open the valve at the bottom to drain the water left in the pipe and cut out the line with pipe cutters.
Then, cut out your hot water line and thermal expansion tank. The tank will be heavy, weighing around 20 pounds, so remove it carefully and have a second person there to help if needed. If your tank is not heavy and you’d like to ensure that it’s still safe to use, press the valve stem at the bottom, and if air comes out, you can still use it. If water comes out, you will need a new thermal expansion tank.
6. Remove water heater tank
Now your heater should be drained, so unscrew the water hose and remove the entire water heater. This is easiest to do with two people, but if there is minimal space, tip the heater on one side and roll it out of the way. Check local codes for proper disposal.
Install the New Water Heater
For this installation, you will need the following:
Preparation
- Teflon tape
- Pipe dope
- SharkBite Max water heater connection kit
- SharkBite Max male adapter
- HoldRite Quick Pan
- Vent screws
Expansion tank
- SharkBite Max ball valve
- SharkBite Max female center slip tee
- Air compressor
Gas and relief lines
- Eastman gas dryer installation kit
- SharkBite Max tee
- SharkBite Max straight stop
- SharkBite Max reducing coupling
- SharkBite Brass push 90-degree elbow
- SharkBite Max straight coupling
- Expansion tank strap
- Spray bottle
Once you’ve ensured the area is clean and dry, unbox your water heater and ensure the flue is set in place at the top of the heater.
1. Prepare water heater connections
To prep your water heater, thread Teflon tape onto the dielectric nipples and apply a small amount of pipe dope. Then, thread the SharkBite Max water heater connectors onto the dielectric nipples.
Next, apply Teflon tape and pipe dope to the SharkBite Max male adapter and thread it into the T&P valve. Then, use pipe dope on the gas fittings and drip leg into the gas control valve. Be careful not to overtighten and hand-tighten the drip leg.
2. Place the new water heater
After tightening the gasket on the HoldRite quick pan, place it where your water heater will be and roll the water heater close to the pan. With two people, carefully lift the water heater and place it into the pan or use a strap to lift the heater. Once it’s in place, secure the draft hood into the tabs on the top of the heater with four screws and secure the vent to the hood with at least three screws.
3. Make your water heater connections
Now that the water heater is in place, install the SharkBite Max ball valve. This will allow the thermal expansion tank to be serviced separately from the rest of the water heater.
a) Deburr the cold water line with the deburr and gauge tool.
b) Measure and mark the pipe according to the correct insertion depth.
c) Push the ball valve onto the pipe.
Next, install the SharkBite Max center slip tee between the Max ball valve and SharkBite water heater connector.
To connect to the ball valve:
d) Measure the length of pipe that will be between the ball valve and center slip tee. Include the insertion depths of both fittings in this calculation.
e) Squarely cut and deburr the pipe.
f) Measure and mark the pipe according to the correct insertion depth.
g) Push the center slip tee onto the pipe.
To connect to the water heater connector:
h) Measure the length of pipe that will be between the center slip tee and the SharkBite water heater connector. Include the insertion depths of both fittings in this calculation.
i) Follow the directions from b and c.
j) Push the SharkBite water heater connector onto the pipe.
Moving onto the hot water side, deburr the pipe and measure and mark the insertion depth before pushing the connector onto the line. Then, fully tighten the base of both connectors with tongue and groove pliers.
Read More: How To: Install SharkBite Max Fittings
4. Install the expansion tank
To install the thermal expansion tank, use the psi you measured earlier and set the tank to that exact pressure with an air compressor. If it doesn’t match your home pressure, the diaphragm will rupture and fill with water, becoming a deadweight. This uneven pressure would weaken the expansion tank, allowing your water pressure to reach up to 80-120 psi. Always test, calibrate and charge your thermal expansion tank to match your home water pressure.
Then, use Teflon tape and pipe dope to prep the threads on the tank. Once the tank is charged to the correct psi, fully tighten it onto the center slip tee you installed earlier.
5. Fill up the water heater
Now it’s time to fill up the water heater, so go to your main water line and ease it back on. Then, check that your connections are secure by opening and closing the two ball valves. After opening the T&P valve to bleed the air out, you are ready to install the new gas line.
6. Install the gas line
Using the Eastman gas dryer installation kit, install the adapter included in the kit, if needed, and apply a small amount of pipe dope to them. Then, thread on the gas connector and open the gas valve. Immediately let air out of the drip leg until you smell gas. This does not require taking the drip leg out completely, but slightly opening it on one side.
Once you smell gas, fully tighten it onto the threads. Press the pilot down for around 30 seconds and start striking it until it’s lit. Keep holding the pilot until you hear the click and see the light indicator. Let go of the pilot and adjust the settings on the gas control valve, as needed. Now, the water in the tank will start heating up.
7. Assemble the relief line
A tee is necessary for this specific installation to ensure the pipe can reach the existing plumbing. To install the SharkBite Max tee:
k) Measure the length of pipe that will be between the SharkBite Max male adapter and the Max tee. Include the insertion depths of both fittings in this calculation.
l) Squarely cut and deburr the pipe.
m) Measure and mark the pipe according to the correct insertion depth.
n) Push the Max tee onto the pipe.
To install the SharkBite Max straight stop:
o) Measure the length of pipe that will be between the SharkBite Max tee and the Max straight stop. Include the insertion depths of both fittings in this calculation.
p) *If your tee and stop require two different pipe sizes, use a SharkBite Max reducing coupling to adapt. This requires another piece of pipe.
q) Follow the directions from b and c for all pipes.
r) Push the Max straight stop onto the pipe.
For this home, Ben used a SharkBite elbow to extend the relief line out. This is needed to connect the relief line to the existing pipe. To install the SharkBite elbow:
s) Measure the length of pipe that will be between the SharkBite Max straight stop and the elbow. Include the insertion depths of both fittings in this calculation.
t) Follow the directions from b and c.
u) Push the elbow onto the pipe.
Lastly, make the final connection to join the relief line to the existing pipe in your home. Make sure all connections are made with deburred, measured and marked pipe. To install the SharkBite Max coupling:
v) Measure the length of pipe that will be between the top end of the SharkBite elbow and the SharkBite Max coupling. Include the insertion depths of both fittings in this calculation.
w) Follow the directions from b and c.
x) Push the coupling onto the pipe.
8. Check your gas connection
Next, use a faucet to bleed the air out of the relief line for a few minutes and fill up your spray bottle with soap and water. Then, spray the gas line connections, avoiding the gas control valve. If you have a gas leak, bubbles will start to blow, but once you have confirmed there are no gas leaks, wipe off the soapy solution. Expect the water heater to finish heating after one hour.