Safety valves
Safety valves are critical overpressure protection in closed heating, cooling and water supply systems. This safety equipment ensures that the system pressure does not exceed permitted limits, thereby protecting equipment from rupture or damage in accordance with the strict EN ISO 4126 standards.
Safety valves by purpose: Watts and Danfoss
When choosing a valve, it is necessary to distinguish between drinking water and closed heating systems:
- Watts SVW: Designed for potable and hot water (DHW). Distinguished by a blue handle and meets high hygiene requirements. (Please note that the Watts SVH series with a red handle is for heating only).
- Danfoss BVA: Designed for boiler houses and closed heating systems. These valves are not used for preparing domestic hot water.
Boiler safety groups (Reflex SG, Caleffi 526)
To simplify installation, a combined boiler safety group is often used. These assemblies, such as the Reflex SG or Caleffi 526, combine in a single body a safety valve, a pressure gauge for pressure monitoring and an automatic air separator. This ensures comprehensive protection of the heat source and more convenient maintenance.
How to choose a safety valve?
- Certification: The equipment must comply with the EN ISO 4126 standard and the requirements of CE marking and PED (Pressure Equipment Directive 2014/68/EU).
- Set pressure and discharge capacity: The valve's connection diameter (DN) and discharge capacity are calculated according to the maximum capacity of the heat source.
- Industrial solutions: For steam and large industrial processes we offer flanged valves (DN50 and larger) from manufacturers such as Herose, LESER or ARI Armaturen.
Installation and maintenance requirements
- No shut-off fittings: Installing any gate valves or shut-off valves between the heat source and the safety valve is strictly prohibited.
- Discharge pipe: The discharge line must be no longer than 2 metres, have no more than 2 elbows and no traps. A visible discharge (a funnel with an air gap) is required so that staff notice a leak immediately.
- Testing: The valve's operation must be checked at least once a year by briefly turning the handle and letting water flow through.
Frequently asked questions (FAQ)
1. What should the system working pressure be relative to the valve setting?
The set opening pressure must not exceed the maximum permissible system pressure. For the valve not to drip and to reseat tightly after opening, the normal working pressure should be at least 10-20% (or about 0.5 bar) below the valve's set limit.
2. What are T&P valves and where are they used?
T&P (Temperature and Pressure) valves are combined temperature and pressure safety valves, most often used on storage water heaters (boilers). They open not only when the pressure rises but also when the water temperature reaches a critical limit (usually 90-95 °C), thereby protecting the boiler from overheating and possible explosion.
Looking for reliable overpressure protection for your project? In the Amegata range you will find solutions that meet the strictest standards. We also invite you to look at our control valves and thermostatic valves for balancing and controlling the system. Need advice on selecting a safety valve or a complete boiler safety group? Contact our specialists!