We believe in offering our installers expert support. No matter if it’s the first time you try one of our products, or if you run into extremely challenging situations.
You need to reduce the water temperature to prevent scalding.... but at temperatures below 60ºC, there is risk of legionella bacteria growth
- It takes 1,5–2 minutes to achieve a scalding injury in 52°C hot water.
- At 57°C it takes 10 seconds to get scalding injuries.
- 60°C hot water gives scalding injuries of third degree in less than 3 seconds.
The 1…6 marking on the knob is an indication of mixing temperature setting steps of the valves temperature range. The temperature step between every setting is approximately 4°C / 5°C.
However, to set the mixing temperature in accurate way we need to secure flow volume above 4l/min for VTA300 series, and above 9l/min for VTA500 series, and measure the temperature in a point of use for more than 60s.
The valves should be selected based on the needed water flow, application area and system conditions, not by pipe size.
ESBE has created quick guides to make selection easier, and below you can find two different tables.
First table speaks about the application area, and the second one about the Kvs value in several applications under specific conditions.
For more information please contact customer service.
In case of thermal disinfection, the system needs to be flushed and heated above 70°C to the tap. To achieve this the tap needs to be opened. The biggest risk of legionella growth is in “blank” spots where the water is not moving and in tanks where the water is standing still for a longer time and have lower temperatures. In circulation pipes water is moved much more frequently compared to the potable water pipes/tanks, and at the same time the goal is to keep the water on certain temperature level.
Legionella growth is low when temperatures of the PHW are kept high and the water is moved. The chart below shows how quickly legionella dies in relation to the temperature and time:
ESBE has a product for systems with hot water circulation called VTR300, more information is available on the product page.
You can also use VTA320 or VTA520, depending on the flow capacity needed. You should never use a VTA310 in this type of applications.
The VTD300 is a thermostatic diverting valve developed for these applications. You should not use a VTA300. If you need higher flow capacity the VTA500 series can be used as a diverting valve.
To get the right tap temperature you need:
The VTF320 is a 2-way thermostatic flow limitation valve dedicated for potable hot water circulation systems.
The VTF320 is a thermostatic valve which limits the flow in a potable hot water circulation system depending on the water temperature. When the potable hot circulation water temperature increases the VTF320 will start to close, which will result in flow reduction. If the temperature exceeds 55°C the valve will close, and flow of PHW-C will stop.
The benefits are system optimization and reduction of energy usage as well cost reduction.
The optimization of the system is connected to the energy and cost savings. If we have several zones with PHW-C we can, thanks to VTF320, have control over the zones.
In practice it means that if one of the zones has reached temperature of PHW-C it will be shut off, while the other ones which have not reached the correct temperature will continue to be heated until they reach a temperature above 55°C.
No high temperature water flow means no heat loses, which means no warm water preparation is needed, this is valid for shutting off the zones. By not heating the zones which already reached the target of PHW-C we decrease the energy needed for the circulation pump, heat loses, PHW preparation. This optimization of the system generates savings!
ESBE AB, Bruksgatan 22
SE-333 75 Reftele, Sweden
Tel: +46 371 570 000
E-mail: [email protected]