Top Tips on New Water Heater Installation & Replacement

40 gallon gas water heater

Nothing gets more annoying than to witness their water heater going all cranky on a Sunday morning. That’s when you are just in the mood to spend the day just sitting around and being lazy at home. Now what? And what’s next? Where do we find our plumbers? Who services water heaters  on a Sunday? Well, this article is a complete guide to help you replace your water heater with a new one with easy steps.

Step 1: Selecting the new water heater

When the old one goes bad and a new one is found to replace it, make sure you buy it with the same fuel type either propane, gas or electric. You can select a different water heater but make sure if you are wanting to upgrade to a larger size then make sure have you enough space left from the wall for the larger capacity water heater to fit.

Step 2: Prepare the installation

This guideline list will assist you in some decisions you might have when replacing your water heaters

  • Check plumbing

Measure the dimensions between the hot and cold water pipes which are on the top of the water heater and make sure the new heater has the same size to fit. Installation is easier if you measure things before starting the replacement. The gas union should be there in the gas line if it’s a gas heater but not if it is a water heater and make sure there is a shutoff for the cold water inlet pipe and a union connector for the hot water outlet pipe. If you don’t have them then cut the pipes from the old heater and install the cold water shut off valve or the hot water pipe union.


  • Setup

This stage requires two people to do a good setting for the new heater, so make sure you have a helper as well. As the heater is heavy it is a good idea to have a rented appliance dolly for time and expense saving.

Step 3: Turn off the utilities

Turn off the water utilities connecting to the water heater whether it is on the electric mode or gas. Turn off the water’s main valve at priority.  If you have an electric water heater, shut off the electricity to the water heater by eliminating the fuse or turning off the water heaters circuit breaker.  If your tank is run on gas, there will be a gas cock on the gas supply line for the water heater. In either case, make sure you turn it off and disconnect the gas line.

Step 4: Drain the hot water

The 4th step is to drain the water from the tank once the water is turned off. Now open the hot water faucet and attach a hose to the drain valve on the water heater. Drain the water by placing another end of the hose or pipe to the floor and open the valve.

Step 5: Disconnect utility lines, remove and replace

Next step is to disconnect the utility lines whether it’s the electric heater or the gas heater. Disconnect the flue from the heater and once all the modes are disconnected, here you get all ready to remove the old heater and replace it with the new one. Remove the old heater, clean the place, move the new heater into the position of the old heater. Use a torpedo level, level the new water heater until it gets in the right position.

Step 7: install fitting, Connect electric or gas pipes (as per requirement)

Install the fittings, usually ¾ copper flex lines by attaching the connections to the old water heater’s location with the help of a helper. Set the temperature in accordance with the requirements. Now connect the electric or gas pipes to the new heater. Use flexible copper supply lines if you are not able to fix the new inlet and outlet openings that the old heater had. Connect the pipes using the dielectric unions to prevent an electro-galvanic action called electrolysis which will damage your pipe connections and water heater unless you are using pex water pipe.

Step 8: Attach flue and set temperature

If you are fixing a gas water heater then attach the flue by attaching the draft diverter over the water heater flue. Make sure you read the new heater installation guideline booklet. Now fill the heater tank with cold water, once it is filled switch on the main gas, then light the pilot to heat the water.