2115 diaphragm safety valves are used to protect liquid-filled pressure systems against exceeding the required pressure. They are used primarily to protect domestic closed water heaters. The choice of valve size, depending on the tank volume or heat output of the rotary heat exchanger, is shown in the table in the manufacturer’s data sheet. Valves can be selected using a software, available to download as a compressed file. Relief valves can be used in pressurized water systems and with other perfect fluids with a maximum temperature not exceeding 110°C. SYR relief valves can be used in systems filled with a mixture of water and glycol The maximum glycol content must not exceed 50%.