Water heaters are supposed to have periodic maintenance but all too often they are just a forgotten appliance that works, and works for you until one day it’s had enough, and it quits due to rust and corrosion.
The quickest and easiest way to replace a water heater is to have it done by a plumbing professional, but if you can’t afford it or really want to do this yourself, then read on. You need to make sure you’re following plumbing codes so calling your local plumbing inspector to find out what municipal permitting requirements and specific criteria they may have is a good idea. Replacing a water heater is not extremely hard. However, it will probably take the better part of a day to complete.
Selecting Your New Water Heater
When selecting your new water heater it’s easiest to keep the same fuel type, whether gas or electric. This article is based on you using the same fuel type when replacing yours. However you cam change the size a bit. For example, let’s say you had a 40 gallon and want to go to a 50 gallon. That should not be a problem as long as you have clearance between the heater and the wall.
Prepare for the Installation
Before you start, check these next points to make sure you’re ready to go when the new water heater arrives.
Check the Plumbing
Measure the center-to-center dimension between the hot and cold water pipes on the top of the water heater and try to ensure the new heater has the same dimensions. That will make the plumbing job a bit easier. Take a look at the plumbing connecting to the old water heater. Make sure you have a gas union in the gas line if you have a gas water heater, and make sure there is a water shutoff for the cold water inlet pipe and a union connector for the hot water outlet pipe. If you don’t have these you’re job is a bit harder as you’ll have to cut the pipes to remove the old heater, then install the cold water shut off valve, and / or gas union or hot water pipe union. But most plumbers did the right job in the beginning so hopefully everything is in place.
Getting the water heater off the truck and into place is usually a two person job. I also recommend using an appliance dolly if possible. If you don’t have one, you can rent one for around $20/day it makes moving the new heater around a lot easier. They are bulky and heavy. Once you have the new heater brought to the location of the old heater you’re ready to go.
Turn Off Utilities to Water Heater
Before you do anything, you have to turn off the utilities to the existing water heater.
Turn off the water at the home’s main water shutoff valve or the shutoff valve at the cold water supply line running to the existing water heater.
If you have an electric water heater, shut off the electricity to the water heater by removing the fuse or turning off the circuit breaker on the water heater’s circuit.
If you have a gas water heater, turn off the gas at the gas supply pipe at the tank or at the main gas shutoff valve to the home. To make sure the gas is off check the pilot light, it should be out.
Drain the Hot Water Tank
Once the water is turned off to the heater you need to drain the tank.
Open the nearest hot water faucet.
Attach a hose to the drain valve on the water heater.
Place other end of hose over a floor drain.
Open the drain valve slowly so that sediment does not clog the drain valve.
Disconnect Utility Lines
Disconnect the hot water, cold water, and depending on the type of water heater, the gas line or electrical service to the water heater.
If you have a gas heater, making sure the gas is off disconnect the gas line to the water heater.
If you have an electric heater, disconnect the electrical service to the water heater.
To remove the plumbing you may need a pipe wrench, slip joint pliers, or channel locks.
Disconnect the cold water line by disconnecting it at the shut off valve to the heater.
Disconnect the hot water discharge line by disconnecting the hot water line at the union to the heater.
Disconnect the flue from the heater.
Once the flue, water lines and gas or electric service have been disconnected you are ready to remove the old heater.
Remove and Replace the Water Heater
Once the old water heater is fully drained and disconnected, you may remove the old unit.
Have an assistant help to load the old water heater onto the appliance dolly and remove the old water heater.
Clean up the floor where the old heater was located.
Move the new water heater into position lining up the existing plumbing with the water heater’s plumbing locations.
Using a torpedo level or full level, level the new water heater by shimming under the legs until the unit is straight up and down.
Install New Water Heater Fittings
Next, install the various fittings that come with the water heater.
Install the temperature and pressure relief valve and discharge drain pipe.
Use Teflon tape on copper and pipe dope or joint compound on galvanized fittings.
Install any other fittings as per manufacturer’s directions.
Connect Hot and Cold Water Lines
Next, install the plumbing lines to the water heater.
If the new water heater inlet and outlet openings do not line up exactly with the old plumbing, then use flexible copper supply lines.
Add a shut off valve to the cold water supply if one dose not already exist.
Connect the pipes using dielectric unions to prevent an electro-galvanic action called electrolysis which will damage your pipe connections and water heater.
Sweat the copper joints or use Teflon tape on threaded copper, and use pipe dope or joint compound on galvanized fittings.
Connect Gas Line or Electric (as applicable)
Once the water lines are installed you’re ready to install the fuel source.
Connect the gas line to the gas burner control valve.
Use a flexible gas line if needed.
Check for leaks by turning on the gas supply valve and brushing on a soapy water solution onto the gas union and all gas joints, like that at the burner control valve. If you see any bubbles, the connection is leaking and needs to be tightened. If you still cannot get a good seal without bubbles, call the gas company or a plumber for assistance.
For electric water heaters, connect the power lines and ground wire to the water heater junction box.
If the water heater is a gas model you next need to attach the exhaust flue
Attach the draft diverter over the water heater flue. There should be specific parts and instructions with the new water heater. Install the flue as per manufacturer instructions and local codes.
Once all the connections are made, it’s time to fill the water heater up with cold water and turn the unit on.
Turn on the cold water supply valve to the water heater and turn on the main water supply valve at the water meter if that was also turned off.
Close the faucet near the water heater that was opened when you drained the water heater.
Fill the water heater tank. One way to check when it is full is to turn a hot water faucet on in a remote bathroom or the kitchen and when water comes out of that faucet, the tank is filled. The water will still be cold.
Once the tank is filled turn power back on at the power panel by reinstalling the fuse or resetting the circuit breaker (if an electric model); If a gas model, make sure the main gas valve is opened and light the pilot.
Set the thermostat to a temperature between 110 and 130 degrees.