Temperature & Pressure Relief Valve

For Hot Water Storage Buffer system

Temperature and pressure relief valves are used in residential and commercial water heater and hot water storage tank applications to provide automatic temperature and pressure protection to hot water supply tanks and hot water heaters.

Temperature and Pressure Relief Valves is suitable for Installing at the Pressurized solar water heater, gas heater, electric water heater , water heater of fuel, heat pump water heater , sensitive function heater, etc. various kinds of heaters( such as the boiler) and hot water containers . The valve will be opened at the set temperature and pressure to protect the water tank.

A temperature pressure relief valve is a valve that’s located somewhere near the top of your water heater. The valve has a lever that can be lifted up or down and a discharge pipe that runs from the valve straight down to the bottom of your water heater.

The purpose of the temperature pressure relief valve is to release water, and in turn lower the pressure inside the tank, in the event that the temperature or pressure gets too high in your water heater. Without a temperature pressure relief valve, your water heater would run the risk of exploding if the temperature or pressure got higher than the tank was designed to handle.

Operating Principle

The valve opens the outlet on reaching the settings for:

– temperature: the thermostat compound inside the temperature sensor 1) submerged in the hot water storage heater, expands as the temperature increases. This expansion causes a thrust pin to move and act on the obturator 2) opening the valve. The valve is set to open at temperatures of over 90°C.

– pressure: the obturator, opposed by a set spring, raises on reaching the pressure setting and opens the outlet completely. The pressure setting is chosen according to the maximum permissible pressure in the system.

As the temperature and pressure decrease, the opposite action occurs with the valve subsequently reclosing within the set tolerances.

Technical Specification

  • Set Pressure(Psi): 75,87,100,125,150psi (0.5,0.6,0.7,0.8,1.0MPa)
  • Set Pressure Tolerance: +5%,-10% of the set pressure.
  • Set Temperature: From 65°C to99°C. (As you’re required)
  • Set Temperature Tolerance: 99°C-5°C; other set Temperature is ±5°C

MODEL Size Inlet× Outlet A B D T Weight Temp. Steam
in in mm mm mm mm (g) Rating BTU/hr
VWYA-15 1/2 1/2×1/2 41 83 31 100 -205 15000
VWYA-20 3/4 3/4×3/4 42 83 31 100 -222 105000


The installation of temperature and pressure relief valves is critical. They must be installed so that the temperature sensing element is immersed in the hottest water in the tank. The hottest water is located in the top six inches of the tank.

Most water heaters are equipped with a special tapping for the T&P valve at the proper location in the tank. If, however, the valve were to be installed a distance away from the tank, a thermal lag condition would be created, which simply means that the valve thermostat cannot respond to the hottest water in the top of the heater.

For example, a ¾ ” valve which is installed four inches from the tank would actually be sensing cooler water, and by the time the temperature of the water at the point of the valve reached 210°F, the temperature at the top of the tank would be 244°F. Another example: If the valve was installed ten inches away, when it finally sensed 210°F water, the temperature at the top of the tank would be 272°F.

So the basic rule is to install the valve so that the temperature sensing element is immersed in the water in the top six inches of the tank. This may require the installation of an extended temperature sensing element.

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