Ironically, the ordinary garden hose is the most common offender as it can be easily connected to the potable water supply and used for a variety of potentially dangerous applications.

backflow prevention valve - bunnings

If appliance warranty was not enough, without a pressure limiting valve you may not be covered by your insurance company. If an appliance or fixture fails as a result of high water pressure you may not be covered by insurance.

Backflowpreventerirrigation

We understand that all of the plumbing jargon can be a little bit overwhelming. That is why we have decided to talk about a few of the most common plumbing terms and requirements in order to help you understand and feel comfortable with what may be happening or may need to be happening at your house. Today we are talking about a pressure limiting valve.

BackflowPreventerWatts

Absolutely not! If there is an increase in the downstream pressure over that of the supply pressure, the check valve would tend to "modulate" thus permitting the backflow of contaminated water to pass through the orifice into the potable water supply line.

The Australian Standards also state that any new buildings or extension work done to your plumbing requires the installation of a pressure limiting value. Failure to do this means that your building does not comply. The standards go on to say that ‘pressures above 500kPa can cause damage from water hammer, reduced life of appliances, taps and fittings, and cause excessive noise in the system.’

Backflowpreventerbidet

Pressure vacuum breakers may be used as protection for connections to all types of non-potable systems where the vacuum breakers are not subject to back pressure. these units may be used under continuous supply pressure. They must be installed above the usage point. (Spill resistant models for indoor use are also available).

Firstly, The Plumbing Code of Australia and the Australian Standards (AS/NZS 3500)  require that water pressure on your property must not exceed 500kPa. Water mains pressure may be considerably greater than this.

BackflowPreventerprice

They may be used where the degree of hazard is low, meaning the non-potable source is polluted rather than contaminated.

Backflowpreventerreece

Fire protection systems are most commonly constructed of uncoated black iron pipe which is considered by plumbing officials to be unacceptable as water system piping material.

A pressure limiting valve (PLV) is a valve that reduces the pressure of the water which flows through it. Water mains pressure can reach extreme pressures and without a pressure limiting valve the pipes in your house could reach this pressure too.

A cross-connection is a direct arrangement of a piping line which allows the potable water supply to be connected to a line which contains a contaminant. An example is the common garden hose attached to a tap with the end of the hose lying in a pool of muddy water. Another example would be a garden hose attached to a tap with the end of the hose submerged in a tub full of detergent.

Irrigation backflowpreventerbunnings

Backpressure backflow is the reversal of normal flow in a system due to an increase in the downstream pressure above that of the supply pressure.

If you have any questions feel free to call one of our friendly plumbers today on 1300 155 944. At Exeter Plumbing we are always happy to help.

While the Plumbing Code of Australia and the Australian Standards require pressure limiting valves, so do many manufactures of appliances and fixtures. Many manufactures of taps, showers, hot water systems and washing machines, just to name a few, set a maximum inlet water pressure. Water pressure which exceeds their maximum voids their warranty.

They can be used anywhere you need to protect direct connections from foreign material that might enter the potable system in concentration which does not constitute a health hazard.

Hose tap vacuum breakers are small inexpensive devices with hose connections which are simply attached to taps wherever there is a possibility of a hose being attached which could be introduced to a contaminant. However, like the atmospheric vacuum breaker they should not be used under continuous pressure.

This term is applied to an installation in which the pressure is being supplied continuously to a backflow preventer for periods of over 12 hours at a time. Laboratory faucet equipment, for example, is entirely suitable for a non-pressure, atmospheric anti-siphon vacuum breaker because the supply is periodically being turned on and shut off. A vacuum breaker should never be subjected to continuous pressure unless it is of the continuous pressure type and clearly identified for this service.

Back siphonage can be created when there is a stoppage of the water supply due to nearby fire-fighting, repairs or breaks in city main, etc. The effect is similar to the sipping of a drink through a straw, which induces a flow in the opposite direction.

Back pressure backflow is created whenever the downstream pressure exceeds the supply pressure which is possible in installations such as heating systems, elevated tanks, and pressure producing systems. An example would be a space-heating boiler operating under 103 to 138 kPa coincidental with a reduction of the city water supply below such pressure (or higher in most commercial boilers). As water tends to flow in the direction of least resistance, a back pressure backflow condition would be created and the contaminated boiler water would flow into the potable water supply.

Back siphonage is the reversal of normal flow in a system caused by a negative pressure (vacuum or partial vacuum) in the supply piping.

Backflowpreventersewer

The most commonly used atmospheric anti-siphon vacuum breakers incorporate an atmospheric vent in combination with a check valve. Its operation depends on a supply of potable water to seal off the atmospheric vent, admitting the water to downstream equipment. If a negative pressure develops in the supply line, the loss of pressure permits the check valve to drop sealing the orifice while at the same time the vent opens admitting air to the system to break the vacuum.

If you have any questions feel free to call one of our friendly plumbers today on 1300 155 944. At Exeter Plumbing we are always happy to help.

Atmospheric vacuum breakers may be used only on connections to a non-potable system where the vacuum breaker is never subjected to back pressure, and is installed on the discharge side of the last control valve. It must be installed above the usage point. It cannot be used under continuous pressure. (Also see #7)

We hear you. Who doesn’t like a shower massage. You do not need to worry. A pressure limiting valve set at the correct kPa will still enable you to have great shower pressure.

Below is an example of water pressure before and after a pressure limiting valve was installed. This particular series is by one of our Plumbers Kurt.