Open Feed & Expansion Tank (OET)
Open Feed & Expansion Tanks serve the dual purpose of:Overcoming pressure fluctuations from expansion within the system and Preventing backflow to mains water supply. This is the oldest method of expansion accommodation in closed loop systems.
Separators & Filtration Systems
Valves & Ancillary
Valves & Ancillary
Economical, reliable and convenient
There are 2 methods of combating the pressure fluctuations in a system caused by thermal and pressure changes – Atmospheric and Pressurised. The OET utilises the atmospheric method. Before the advent of closed expansion vessels, (see our Aquazone section) it was via a header tank, commonly referred to as an open expansion tank, installed at the highest point in the system. These were often large cylindrical tanks made from copper or stainless, with a ball float installed within the tank to allow water infill as necessary from an external source (mostly from town water supply). The tank would have an overflow and drain and a safe tray. Masterflow has designed a standard range to suit most applications and offers custom design tanks for space limiting situations.
Standard nominal tank capacities:
- 35 litres
- 60 litres
- 100 litres
- 200 litres
- 300 litres
- 500 litres
- 650 litres
Features typically include:
- Made from 304 grade stainless steel
- Come complete with safety tray and lid
- Approved float valve for mains supply into the tank
- Non-metallic supports for positioning between the tank and the tray (as detailed in AS 3500) can be supplied if required. (minimum 12mm thick)
- Wall brackets can be supplied (optional extra).
WE CAN HELP YOU CHOOSE THE RIGHT Open Feed & Expansion Tank (OET) FOR YOUR PROJECT
By designing a standard range, available either ex-stock or within a short time frame, Masterflow offers the convenience for competitive value.
Royal Australian College of Physicians
Frequently asked Questions
You have the following options when it comes to closed loop systems. 1. An open expansion tank is the simplest for small volumes, where the tank can be easily placed high enough above the highest point. 2. A closed expansion tank with an RPZ valve can be used anywhere that is convenient, provided it is connected to the return line of the system. Provided the mains pressure is high enough to pressurize and fill that expansion tank it will work correctly. The downside is that the RPZ valve does require regular testing. (annual testing). 3. The same expansion tank could be supplied with a refill unit which includes a break tank. This tank will protect the water supply from contamination as per the open feed tank.
Masterflow is and has been a trusted name among Australia’s HVAC suppliers for over 20 years. We supply a wide range of pump types and can provide the ideal solution to the many and varied fluid requirements that face the industry. We pride ourselves on remaining agile, innovative, and having fast turn arounds. We are local! All our pumps are locally designed, built and manufactured here in Australia.