If you have experience with basic plumbing, you can probably install a water heater on your own. Doing it on your own can save you from having to pay a professional to do the work. If it is your first time working on water heater installation, you should be aware of a few common mistakes, so you do not end up needing to call a professional anyway.
Soldering too Closely to the Tank
A new water tank needs to have the connectors soldered to the existing pipes in your home. It is important that you do not do any soldering close enough to the tank to have the plastic fittings on the tank melt. To avoid this, you can take the nipples off the tank, remove the fittings from the pipes, solder them on a workbench and then put everything back together.
Using the Wrong Connectors
When the pipes in your home have copper fittings, you can use either copper or brass connectors. However, if the fittings or the tank nipples are made of steel, you will need to use a dielectric fitting between the two to keep the nipples and pipefittings from touching and creating an electrical charge. This charge can corrode the metals so that they leak anytime water passes through them.
Fill the Tank Before Turning it On
The first time you are going to use the hot water in the tank, you need to be sure that the tank is completely full before turning it on. You should also turn the water on in a sink or tub, letting it run, while turning on the hot water heater the first time. Turning on the water keeps the water flowing in as it is flowing out. If you allow the heating element to come on before the tank is full, it can cause the element to burn out. This will require either having a professional install a new heating element or buying a new unit.
Installing a water heater is not difficult, but it is also not without its problems. Do not attempt to rush through the process. Plan on taking most of the day to complete the task. Think through each step, starting with shutting off the water, power and/or gas to the unit before you start. Once you are sure the unit is connected with no leaks and have filled the tank, turn it on, wait a bit, and enjoy a nice, hot shower.