Double checkvalvevs RPZ

Whilst both the hydronic and electric system can be used in most applications there are some additional points to consider:

Once an underfloor heating system is installed there is little chance of anything going wrong with either a hydronic or electric system. If, however there was an issue an electric system would be easier to locate than a hydronic system.

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An electric underfloor heating system has a lot faster heat up time. It takes approximately an hour for an Undertile system to heat up and cool down so this allows you to set the schedule to have the heating on exactly when you need it and be able to change it to suit sudden outside temperature changes.

A hydronic system is more complex to install and would require a plumber. Typically, you will need to engage a professional company for installing a hydronic system to ensure the install is carried out correctly to ensure you get an even spread of heat throughout the floor.

If you haven’t read our brief post on the differences between DC and RPZ backflow preventers, take a moment to familiarize yourself with their distinction.

Backflow enclosures were designed with RPZ installation in mind. ASSE 1060 regulations ensure that backflow enclosure manufacturers are designing their products with function and safety in mind. ASSE 1060 testing strictly requires that backflow enclosures provide a drain for when the RPZ inevitably dumps water. For backflow preventers sized 4" and larger, the drain must be able to move 710 gallons per minute.

Both Hydronic and Electric Underfloor Heating systems can be controlled by a programable Thermostat. With an In-Slab system you have a lot less control as you will need to allow 1-2 days for the slab to heat up and then the same amount of time to cool down. This means you don’t have the ability to suddenly turn on the heating or turn off the heat with changes in the weather.

Backflow preventers work by letting water flow through them in one direction, but prevent water from flowing back through them in a reverse direction, protecting the water supply. A commercial building or industrial plant can use all the water it wants, but once the water has passed through the meter and the backflow preventer, it will not be allowed back into the water supply. An RPZ provides the best level of protection because of its relief valve, which will open up and dump the water as a last resort to prevent contamination.

Reduced pressure zone (RPZ) backflow assemblies are extremely important. They’re used to keep contaminated water out of the public supply and provide the highest level of protection.

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Both electric and hydronic systems are going to provide you with the warmth, comfort and luxury that only Underfloor Heating can bring. It can be difficult to know exactly what system is best for your application so if you are still unsure please feel free to reach out to us on 1300 368 631 and one of our consultant’s will be happy to discuss your exact requirement’s.

The install of an electric system is much simpler than a hydronic system. Typically, the install of an electric system is done by an electrician, tiler, builder or even the home owner themselves. The install process is simple, and the system is then tested by a qualified electrician prior to tiling.

Whether you have a hydronic or an electric system it is still recommended to add insulation below the heating to stop downward heat loss as heat moves equally in every direction until it meets a layer of thermal resistance.

A backflow enclosure provides excellent protection against theft and vandalism, not only because of its durability of the enclosure, but also because the device is hidden from view. If an RPZ was to discharge water, backflow enclosures provide visible means to detect it. If the RPZ were dumping water inside a building, water would rise until someone entered the mechanical room, or until the damage was so great it surpassed the mechanical room. A heated backflow cover is a perfect place to install the RPZ, protecting the public water supply and protecting the building from water damage.

Have a question about a backflow preventer enclosure?Click the contact us button below and one of our experts will be able to help with your specific enclosure needs.

Backflow enclosures made to these standards also provide easy access for maintenance and repair. The materials used for RPZ enclosures are designed to withstand the elements and are tested for structural strength as well as security.

An Electric Underfloor Heating system consists of electric heating cables being installed beneath the floor. Electricity then passes along the resistive cables causing them to heat up and radiant the heat into the room. Whilst there are electric systems for in the slab, the majority of electric underfloor heating systems are installed above the slab either directly below the substrate or in a screed.

To see how the RPZ works in various situations, including illustrations and demonstrations of an RPZ in action, here’s a short video.

As with any other piece of equipment, it’s best to understand how the RPZ backflow preventer works in order to determine how to install one for ideal use and function. Sadly, many mechanical or plumbing engineers don't spend much time thinking about the backflow preventer during the project design phase and, in many cities across the country, the backflow preventer is installed inside the building.

By adding a layer of insulation below the heating, you are providing an additional level of thermal resistance which means you are forcing the heat upwards into the room which turns into hot air and rises. Insulation will increase your heat up times and reduce your heat loss resulting in increased efficiency of the underfloor heating system.

Where are RPZ valves required

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This short video shows an RPZ inside an enclosure in action. The relief valve discharge rate charts for a popular backflow preventer manufacturer indicate an RPZ can discharge an incredible amount of water in a very short amount of time. Here’s an example of how much water dumps from this small-diameter RPZ!

As a result, it will take approximately two days to heat the entire slab and turn this into a heat bank and generate heat in the room. Once the slab is warm it holds the heat well and becomes an energy efficient heat bank. However, in Australian most areas experience cold mornings and evenings but have it warm during the day, so this is not an effective or useable form of heat as you are unable to reduce or turn off the heat during the day.

The RPZ will absolutely protect the public drinking water supply, but if installed in the wrong space, it can potentially cause flood damage to the building. It is important to use best practices when installing an RPZ, and the best place for installation is outside in an RPZ backflow cover.

RPZ diagram

With an electric underfloor heating system, a technician can put high voltage down the cable to track where the damage is. This can normally be traced down to a single tile that needs to be lifted and the heating cable repaired.  However, with a hydronic system there is simply a leaking pipe causing the water to run along the outside of the pipes making it extremely difficult to pinpoint the exact location of the leak. As a result, it is more likely that a greater proportion of the floor will need to be lifted in order to locate and repair the leak.

The RPZ clearly indicates whether the valve is working properly or if service is needed. If no water is dumping out of the relief valve, the backflow preventer is operating as intended. If the relief valve is dumping water or spitting out water of any amount, maintenance is required. This clear indication of a system issue is why more and more municipalities across the country are requiring the RPZ for both domestic and fire lines.

With the increasing requirements nationwide for RPZ installation, it’s also important to think about where it should be installed. There are two options: inside in a mechanical room or in an RPZ backflow cover.

Difference between RPZ and backflow preventer

Underfloor Heating is rapidly becoming one of the most common methods of heating used in Australia. With the heating at the floor level, it is an efficient way to heat any room. There are two main forms of Underfloor Heating, Electric and Hydronic.

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A Hydronic Underfloor Heating system consists of a network of pipes running under the floor. Hot water heated by a boiler flows through the network of pipes to heat the substrate and therefore heat the room. Typically, in Australia most Hydronic systems are located in the slab not directly below the floor finish.

In response, there is a growing trend across the country where water jurisdictions are requiring the use of an RPZ backflow prevention assembly. In fact, many areas are now requiring the RPZ on all domestic and fire service lines. So, even if you’re in an area where single checks or double checks were once acceptable, that could change, if it hasn’t already.

Because an RPZ is designed to evacuate water, one has to concede the fact that the surrounding area will get wet. For this reason alone, a RPZ should not and cannot be installed inside a structure. In this picture, the RPZ was installed in a mechanical room. Notice the electrical panels! The plant moved the enclosure outdoors when someone determined this was a dangerous location for the RPZ. Read more about this installation here.