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Posted 11/14/2017

Water Heater Replacement and Installation. A DIY guide

Water Heater Replacement and Installation. A DIY guide

Everybody loves to run a warm bath especially when it is freezing temperatures outside. Winter in the United States can be extremely cold and it can be difficult to take showers if hot water is not accessible to you. It can also be a challenging feat to get hold of a professional plumbing agency to come out and fix your water heater as it malfunctions, for two reasons: firstly they are overbooked with other customer reservations as same as you. Secondly fixing the equipment in the harsh cold winters is a daunting task for them too. So it is recommended to prepare for the brutal winters ahead before they arrive in full swing.

Before you decide to replace your old water heater you must check if the damage is reparable. Everything from bad smells, incorrect water temperature to insufficient supply and unclean water can be fixed except when there is a water leak. When you have a leak, that’s it and you are left with no other option but to replace the unit. Fortunately water heaters have a solid build and do not need as much attention as other HVAC equipment. A regular gas water heater can last up to 10 years before it starts to show signs of degradation. Installing a new water heater can cost between $1000 to $1600.

You will also need to decide the size, fuel and type of water heater you are looking for:

When it comes to size, the water heater should be large and quick enough that hot water is easily available when needed. This depends on the number of people in the house and usage. You will have to pay special attention to the first hour rating (FHR) which represents how much water can be heated within the first hour from a cold start. A family of four might require 90 gallons per day but that doesn’t mean that you need to get a heater with a storage capacity of 90 gallons.

Talk about fuel, you have the conventional gas heaters and the modern electric heaters. Each has its own advantage and disadvantages which you can read up on other articles that we have previously posted. In a nutshell this will determine your maintenance and utility costs for the year.

There are many types of water heaters such as storage vs tankless options and solar vs on-demand water heaters available in the market today. Consult a plumbing agency or an HVAC expert to know which will be perfect for your home depending on where you live.

Water Heater Replacement guide


Firstly you will need to remove the old water heater. Begin to do so by turning off the gas or electricity and then drain the tank of all water that might still be in there. In case of a gas water heater make sure the pilot light is out to avoid any unpredictable dangers. Unscrew any screw holding the sheet metal together and disconnect the gas line. Lastly separate the vent pipe from the draft hood.
In case of an electric heater, use a voltmeter or tester to ensure the circuit is not live. In order to get to the circuit you will have to remove the cover plate to expose the wiring of the water heater. Before checking the circuit, it might be good idea to test your equipment with a tester at a good outlet so you know it’s working properly. Check the different combinations between the two supply wires and the ground wire, which is usually green in color, for any live wires. Do not proceed unless all wires are dead.

Remove all cover plates, screws, and nuts that hold the heater in place to remove the unit from its location.

The next step involves draining the water heater. Attach a hose to the drain valve and place the other end where it is safe to discharge the hot water. Make sure it is not near young children or grass as hot water can cause serious burns and destroy vegetation.

The next part can get a little technical so follow it exactly as described. In order to allow air to enter, you need to turn off the cold water inlet and open the hot water tap. Once that is done, open the drain valve for the hot water to escape through the hose. The outlet end needs to be at lower level than the water heater tank bottom so that it can take a natural flow with the help of gravity.

Remove the hose from the drain valve once all the water has drained out. Grab a wrench and remove any connections with unions and threaded fittings. Soldered pipes unfortunately cannot be removed and need to be cut with a hacksaw or a tubing cutter. Cut as close to the heater as possible and dispose the old heater safely at a dumpsite.

Installing a new one

Align the new water heater to the piping. In case it is a gas model, connect it to the new draft hood and fit the legs on top of the heater to the holes. Gas models need proper venting. The vent pipe should not be smaller than the draft hood collar. If the old pipe is corroded, you will have to replace it with a new one. Connect the vent pipes with the help of short sheet metal screws if you have to.

Use copper-flex-connectors to attach the hot and cold water lines. These can be easily shaped according to your needs. Some soldering may be required where you cut off the old ones. Hook them up to the water heater inlet and outlet. The water heater inlet should be connected to the cold water shut off valve.

To let off excess heat and pressure automatically, the water heater needs to have a pressure temperature relief valve installed. To start filling the storage tank, open the cold water inlet and close the heater’s drain valve. Check for leaks and then open the hot water faucet to release the trapped air at the top of the tank. Lastly, connect the electric or gas lines to your heater.

Follow the instructions that came with the heater. If you are not a qualified electrician, it is better to wait for one rather than venturing out on your own.