What are all the parts of my electric storage water heater and why do I need them all?

Modern water heaters are simple, practical and efficient ways to heat and store water for the home.
Australia has some of the highest installation and safety standards when it comes to hot water in the world. That's why some modern systems look like UFO's compared to their older counterparts.
We have labeled the picture below and given you a brief rundown on the individual parts, their purpose and why they are needed.
A. Tempering Valve. The tempering valve limits the outgoing water temperature to between 45 and 50deg. Its designed to reduce the chance of scalding and serious burns especially with children. The tempering valve self-adjusts with changes of incoming temperatures by sliding and valve with the help of a beeswax thermostat. Tempering valves are legal requirements for all new and replacement hot water systems and cannot be removed or left out.
B. Pressure Temperature Relief Valve or PTR. The PTR valve is designed to release excess water pressure and/or water over 99deg to stop the system possibly becoming explosive. These valves MUST be installed on all systems and drained to an appropriate discharge point and replaced at intervals not exceeding 5 years.
C. Duo Valve. The duo valve is a combination Isolation valve to turn the system off and non-return valve to stop water running back through the system.
D. Expansion Control Valve or ECV. The modern system will release up to 3% of its total reheated volume while reheating due to expansion, meaning up to 7.5L per day for the standard 250L heater. The ECV releases this cold water from the inlet of the cylinder to an appropriate discharge point, in this case, a downpipe.
E. Outlet line strainer. The outlet line strainer catches any lumps before they enter the tempering valve or tap-ware in the house. The lumps are generally calcium deposits created when the water is heated and rust from old systems. This is why we always use AVG valve kits as a lot of cheaper kits do not use strainers.
F. Approved discharge point. All new and replacement systems needs the drains run to an approved discharge point with an adequate air gap. In new homes this is generally installed at the build stage, but in older homes it was generally left out as the excess water was released onto the floor. The drains are not aloud to dump on the floor for a number of reasons but the three main reasons are 1. Termites like damp 2. A wet spot in front of the heater will cause the system to sink 3. A constant wet spot on the ground will turn into mould.
G. Element and Thermostat - These electrical components are what heats the system and make sure the water is only heated to the preset limit, generally 60deg.
H. Sacrificial Anode - One part of the system that is generally forgotten. The anode is designed to be bait for rust and wear out before rust attacks the tank. This is why you need to make sure the anode is replaced every five years. By replacing the anode every 5 years, for around $139 you will drastically lengthen the life of your system, valves and tapware. When you install a system with JR will will send you reminder notices for all service requirements so you can set and forget.