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Contact Andy Hart on 021 365 130 or email info@unitray.co.nz

UNITRAY
HOT WATER SYSTEM INSTALLATION MADE EASY

The UNITRAY concept was born out of the desire to improve the speed and ease of installation of safe trays for hot water units and to ensure that installations are compliant with  AS/NZS 3500 first time, every time. The UNITRAY reduces time, costs and hassles when installing a hot water unit.

UNITRAY BENEFITS

All-in-one compliant safe tray solution. Save time, money and get it right the first time. Supplied with 50mm BSP male outlet coupling that can be trimmed to suit Fernco or fusion welded couplings as shown.

TESTIMONIALS

FAQs

NZ Building Code Acceptable Solution G13/AS3 (AS/NZS 3500.2 as modified by G13/AS3) lists the following table of materials that can be used in sanitary plumbing and drainage systems, taking into account several factors (including the physical and chemical characteristics of the materials and products, the range of temperatures from the discharge that it will be exposed to) and other factors:

Table 1 Pipes , traps and fittings
Paragraph 2.1.1
Meterials Standard
Pipes and fittings
Air admittance valves ASSE 1050 or ASSE 1051 , EN 12380, AS/NZS 4936
Copper pipe NSZ 3501
Copper fittings AS 1589
PVC pipe and fittings AS/NZS 1260
Plastic fittings AS 2887
PE pipe and fittings AS/NZS 4401
Elastomeric rings AS/NZS 4130 or AS 1646
Traps
Plastic AS 2887
Copper AS 1589

The UNITRAY system is made of High-Density Polyethylene (HDPE) and incorporates a safe tray, T-connector and tundish assembly for relief drains*. The system is designed and specified for use with controlled heat source hot water cylinders and in such cylinder systems, there are multiple in-built safety devices such as thermostats, relief valves and thermal cut-out switches that prevent significant volumes of water from being released at excessively high temperatures. For this reason the use of U-PVC piping is accepted by territorial authorities throughout Australia (where the UNITRAY system was initially developed) and we have had confirmation from several consenting authorities, including Auckland Council, of U-PVC’s acceptance in New Zealand jurisdictions.


However, we are also aware of pipe products made of other materials complying with the above Table, such as High-Density Polyethylene (HDPE) and Medium-Density Polypropylene (PP-MD), that are available in NZ and that have temperature ratings above 90 degrees Celsius and which may be selected in installations where there is genuine concern of significant volumes of potentially high-temperature water being released.

For more information, please contact Unitray Technical Support at https://unitray.co.nz/contact/.

 

* The discharge of relief drains via such a tundish arrangement is specifically provided for in G13/AS3 (AS/NZS 3500.2 section4.6.8.1(b))

AS/NZS3500.4 (cited as NZ Building Code Verification Method G12/VM1) specifies certain requirements for safe tray wastes and for placement of water tanks in safe trays.
These requirements include specifications for the waste to have a continuous fall to its discharge point (section 5.4.4.3) and for supports of at least 12mm thickness between the water tank and safe tray covering an area between 50% and 60% of the area of the base of the tank (section 5.4.4.5).
The UNITRAY tee-connector and safe tray comply with these requirements and therefore with the requirements of the NZ Building Code.

  • A specially-designed raised platform incorporating drainage channels is moulded into the base of the UNITRAY safe tray, ensuring that the required area at the base of the water cylinder is supported at the required height as noted above.
  • The UNITRAY is moulded to provide a five degree fall toward the outlet (drainage to the outlet is based on the level installation and positioning of the tray).

The combination of these two features ensure that the UNITRAY system provides that any water discharging from relief drains through the tundish and draining through the tee-connector will drain away from the safe tray and that any spillage that may occur into the base of the safe tray will be prevented from contacting the base of the water tank. The design of the UNITRAY system thereby eliminates the risk of corrosion to the base of the water and the risk of pooled water stagnating in the safe tray.

For more information, please contact Unitray Technical Support at https://unitray.co.nz/contact/

Testing (1, 2) of the UNITRAY safe tray system was carried out to determine the load carrying capability in a simulated worst case scenario involving elevated temperature.


This testing confirmed that a typical UNITRAY (large) safe tray and elevating post installation is more than capable of bearing the full weight of a hot water cylinder containing at least 315 litres of water (combined mass of around 414kg), which is the largest commonly available hot water cylinder system that will fit into the Large UNITRAY safe tray.

This testing has in turn given us confidence that the UNITRAY safe tray and elevating post installation is capable of bearing much heavier loads than the 414kg that has been tested. However, we are satisfied that there is no practical need to do any additional testing beyond the maximum hot water cylinder size configuration that is available on the market and that will fit in the UNITRAY range of safe trays.

For more information, please contact Unitray Technical Support at https://unitray.co.nz/contact/.


1. Unitray Test Report – CPS – 0001, Salt Product Design, 05 April 2017
2. Static and Creep Analysis of revised Unitray HDPE Hot Water Unit Safe Tray, Report 140519 JD, LEAP Pty Ltd – Sydney , May 2014

Under normal circumstances, a TPR valve will only discharge small amounts of water under increased cylinder internal water pressure or progressive wear. When testing, the TPR valve should be eased only and run for short periods but occasionally a TPR valve is triggered at full pressure during testing, which will inevitably result in water flowing into the tray itself.
It is important to note that a full pressure release does not reflect a normal operational scenario. Under normal circumstances or in high sediment areas, where calcium can accumulate under the valve’s seat, a slow flow of water can be discharged out of the valve.
However, in the event of water flowing into the tray due to a pressure release of the TPR valve, the water will soon drain away or evaporate because of the following features:

  • A specially-designed raised platform incorporating drainage channels is moulded into the base of the UNITRAY safe tray, ensuring that the required area at the base of the tank is supported at the required height as noted above.
  • The UNITRAY is moulded to provide a five degree fall toward the outlet (drainage to the outlet is based on the level installation and positioning of the tray).

The combination of these two features ensure that the UNITRAY system provides that any water discharging from relief drains through the tundish and draining through the tee-connector will drain away from the safe tray and that any spillage that may occur into the base of the safe tray will be prevented from contacting the base of the hot water cylinder.

The design of the UNITRAY system exceeds the requirements of AS/NZS3500 and thereby eliminates the risk of corrosion to the base of the water cylinder and the risk of pooled water stagnating in the safe tray.

For more information, please contact Unitray Technical Support at https://unitray.com.au/contact/.

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