As per the requirements of Mr Murphy’s law your hot water system will stop working at the least welcome juncture in your life, usually 5pm Friday in the middle of winter.
Replacing a hot water system with the same type of system (like for like) is usually a relatively painless procedure dependant on the age and design of the existing system. Now days the installation requirements of a hot water heater varies to as it was in the past, so a system replacement may require the addition of several items that were not required at the time of the initial installation, these may include:
• Tempering valve
A tempering valve is a valve that blends hot water with cold water to ensure constant, safe shower, bath and basin outlet temperatures, preventing scalding. It is a requirement under the Australian Standards to supply water not exceeding 50 degrees Celsius to areas used primarily for personal hygiene.
• Cold water expansion valve
Cold water expansion valves are fitted to the cold water inlet to water heater, downstream of the inlet non-return valve. This valve acts as the relief valve in the system and is set at a lower pressure than the Temperature and Pressure Relief valve. The cold water expansion valve will discharge small amounts of cold water as the heater cycles and heats the water creating pressure. By releasing cold water instead of hot, this valve makes the unit more efficient and saves the owner money.
• Thermal insulation
There are minimum requirements for thermal insulation on pipework associated with the hot water heater, these are outlined by Australian Standards. Insulation is required to minimise heat loss and ensure the heater is operating at maximum efficacy.
• Support pad / base
Water heaters, supported on a surface that may become wet shall be installed to allow a free air circulation between the surface and the base of the water heater unless stated otherwise in the manufacturer’s written installation instructions.
• Extension of the drain line to an approved point of discharge
In the past it was common practice to discharge the relief drain line onto the ground surrounding the hot water heater, this is no longer permitted for several reasons (safety, building footings, termites etc). Drain lines must now be terminated at an acceptable discharge point these being – stormwater, sewer or rubble pit (if allowed by local government).
• Heat pump hot water systems now require a lockable switch, AS3000 states –
Air-conditioning and heat pump systems incorporating a compressor shall be provided with a lockable isolating switch installed adjacent to the unit, which isolates all parts of the system including ancillary equipment, from the same location. Exception: The isolating switch may be installed at the switchboard supplying the system if the switchboard is dedicated to the equipment (e.g. an air-conditioning plant room). This work will require a fully licenced electrical contractor to perform the installation. Restricted electrical licence holders cannot perform the installation of the switch.
Other variations may be required when changing hot water heater models (i.e. changing from electric to solar) where pipework may require major changes.
The installation and the replacement of a hot water heater or tempering valve also require the submission of a form 4 (notifiable work) to the state government and the property owner. This form attracts a lodgement fee of $25.90 (electronic lodgement) or a $30.00 fee if manually lodged. Owners should beware if they are not receiving a form 4 at the completion of the installation / repair, if not the work could be substandard or corners could be cut creating a possibly dangerous and non compliant installation and voiding the units warranty. ASK YOUR PLUMBER FOR A FORM 4.
It is also important to note that any and all work relating to the installation and maintenance of a hot water heater is regulated work requiring a plumbers licence. Unlicensed persons performing regulated work face prosecution and large fines not to mention the insurance problems this can create. Insurance claims made in regards to damage caused due to illegally performed plumbing will not be covered by the insurance company.