Expansion Control Valve (ECV) → used to control the increase in pressure caused by water heating up. Most heat pump units have Temperature and Pressure Relief (PTR) Valves that do the same job, so ECVs are not common.
Element → some heat pump hot water units have a backup electric resistance element, a metal rod that heats up when it conducts electricity. Electric resistance hot water is the most common electrically powered hot water service, but it's horribly inefficient and costly to run.
Coefficient of Performance → a number that describes the effectiveness of heat pumps, refrigerators or air conditioners. Simply put, it is calculated by dividing the useful heat supplied by a system dividend by the energy used to run the system.
Condensate Drain → a small drain on the outside of a unit used to drain condensation which forms when the units are running. Condensate drains are often connected to nearby stormwater drains, run to nearby gardens or they can be left to drain on a footpath (not ideal, but not usually an issue, as long as the drain is pointed away from the footings of the house).
Compressor → the moving parts of the heat pump hot water unit. The compressor compresses the Refrigerant, increasing the pressure on it and causing it to heat up. This heat is then transferred into water.
Compressor Rated Input Power → a measure of the power of a compressor. Typically between 500 and 1000 Watts for heat pump hot water units.
GWP → Global Warming Potential - the measure of heat absorbed by one tonne of a gas relative to heat absorbed by one tonne of carbon dioxide (the higher the number, the worse it is)
Impressed Current Anode → anodes that are connected to a power source that provides the tank with a protective electrical current.
Inverters → variable speed compressors that are more efficient to run than traditional fixed speed compressors
TPR Valve (or PTR Valve) → Temperature and Pressure Relief Valve - a valve usually on the side of the unit which is designed to relieve the increase in pressure caused by water expanding when it is heated. Translation - it stops the tank cracking!
TPR Drain Line → the drain line which carries the drips of hot water released by the TPR valve
Refrigerant → a gas/liquid used to effectively transfer and amplify heat from the air into water
Sacrificial Anode → a long metal rod found in many heat pump hot water units, usually made from magnesium or aluminium. The Sacrificial Anode is designed to be more reactive than the tank material, so the rod will sacrifice itself and stop the tank corroding. Sacrificial Anodes typically need to be checked every 3-5 years and replaced every 5 years.
Tempering Valve → it's a requirement under Australian standards to temper the water delivered from a hot water unit. Water is typically heated to 60 degrees to kill off any chance of Legionella. The tempering valve then mixes the water from the hot water service with cold water to deliver water out of the tap at closer to 50 degrees. This effectively eliminates any chances of hot water burns (and yes, the water is still hot enough for a nice warm shower!)
