There are some more tasks that need to be completed on an annual basis. Most of them can be done when you pull the unit out of storage and before you start it for the season. If you are full time then perform them when you do the cleaning of the storage tank for calcium.
BUGS, there are several kinds of bugs that love the smell of propane. If your water heater does not have a bug protector on the exhaust, spend the money an put one on it. They look like a heavy duty screen over the exhaust vent. Each year you want to make sure this is secure and in good condition.
Electric Heating element check. It is probably a good idea to check the condition of the electric heating element. You probably cleaned the tank which should clean the element as well. Over time these heating elements break down and require replacement. The easiest way to check an element is with a VOM (Voltage Ohm Meter or Multi-meter). With power removed from the water heater, measure the Ohms of the heating element. It should be slightly more than 10 Ohms. If it is less than 10 ohms, you will want to replace it.
Safety Valve Check. On the outside of the water heater is a pressure and maybe temperature safety valve. This is used to prevent the pressure in the water heater from exceeding 150 PSI. When water heats it expand and can cause the tank to rupture.
Over time the valves will corrode or become clogged with deposits. That annual cleaning I talked about should help prevent this, but just in case. Each year you want to open this valve.
A. Be careful, the water inside the tank may be hot.
B. Only do this when you are going to drain the tank for cleaning or for storage.
To relieve the pressure in the tank before removing the plug or anode rod, operate the safety valve by lifting up on the little lever on the valve. WARNING: the water may be hot and some of it will come out of the valve. Wear appropriate protection.
Air in tank check. Some of you may have heard about burbing the water tank. This practice is not required and in some cases may damage the water heater. When you fill the water heater for the first camping trip of the season. First make sure that everything is back in it place. The plug or anode rod are installed, the water is turned on and fills the tank. Then go inside and make sure the by-pass has been closed so that water now flows through the water heater. Open a hot water faucet furthest away from the heater and and let it run until the air is out of the system. This will provide the proper amount of air in the water heater to allow for expansion of the water when it heats up. You can perform the same steps at each faucet to get the air out of the lines.
Next article will be about the Aqua Hot and On Demand System Maintenance.