How to Replace a Hot Water Tank

Understanding how to replace a hot water tank is made simpler when you actually set about doing the task. Replacing hot water tank is one of the most common plumbing jobs, all households require at one time or the other. Before you actually begin, read the instructions carefully.

Tools and Materials Required
  • Pipe cutter
  • Voltmeter
  • Pipe wrenches
  • Pipe or tube cutter
  • Metal screws
  • Copper flex connectors
  • Solder gun
  • Screwdrivers
Step 1 - Remove the Old Water Heater

Turn off any electric or gas connection to the heater. For gas heaters, first make sure the pilot light is off. Disconnect the gas line and close it. Separate the vent pipe from draft hood. In case there is a sheet metal screw to hold the pipe in place, remove it.

For electric heaters, remove the cover plate through which the wires go into the heater and check the circuit using a tester or voltmeter. Check between the two supply wires as well as between the supply wires and ground wire. Do not proceed until you are sure that there is no electric current passing through.

Close the valve which provides cold water inlet supply to the heater. Connect a pipe to the drain valve provided at the bottom of the old hot water tank to let the water either outdoors or to a nearby drain. Open any of the hot water taps at home. This will let air inside the hot water pipes to allow faster draining of water from the heater. Open the drain valve to empty the heater.

If the heater is connected with unions or removable threaded fittings unscrew the inlet and outlet fittings of the old heater using pipe wrenches. If the pipe has no unions, it has to be cut using a pipe or tube cutter. Now, the old heater is ready to be removed.

Step 2 – Installing the New Heater

Once the old unit is removed, place the new heater such that the piping reaches easily. For gas heaters, you need to first install the heater’s new draft hood since many draft hoods have legs which slip into the holes at the top of the heaters. Gas heaters need proper venting. The vent pipes should not be much smaller than the draft hood collar. In case the old vent pipe is corroded, replace it with a new one. Keep the vent slope upwards. Use short sheet metal screws to connect the metal pipe.

Connect the hot and cold water lines. Copper flex connectors are commonly used for this since they are easy to bend. If the pipes were cut while removing the old heater, copper flex connectors can be soldered to the cut pipes so that they can be connected to the water inlet and outlet.

Step 3 - Installing Temperature and Pressure Relief Valve

Install relief valve and relief line to automatically let off excess heat and pressure. Connect a pipe from relief valve to some safe discharge place so that sudden discharge of hot water doesn’t harm anyone.

Close the heater’s water outlet valve and open the cold water inlet valve to fill in water. Keep one of the hot water taps open until the air inside is released.

Step 4 - Energy Connections

Follow the instructions given in the instruction manual of the water heater to make the gas or electrical connection. Once they are made perfectly, turn on the connection to check the hot water tank.

The hot water tank is now ready for use. Just make sure you have done everything with due diligence. A little negligence can lead to serious damage.