Protection against thermal expansion

What is the purpose of a safety valve on a water heater?

Here’s a simple example to help you understand the purpose of a safety valve. If the water heater’s thermostat is not correctly set, if an element overheats or if there isn’t enough water in the tank, over-pressurization might occur, and excessive pressure is put on the equipment. This is where the safety valve comes into play. When the pressure in the tank gets too high, the valve opens to release steam. This allows the excess pressure to escape and prevent serious consequences like a ruptured tank or burst pipes. In sum, the safety valve’s purpose is to prevent hazards.

Why is it necessary to have a protection device against thermal expansion?

First, let’s define the terms “thermal” and “expansion.” The word thermal is an adjective that relates to heat and temperature. As for the word expansion, when an object expands, it grows from its original size. Now, let’s explain why it’s important to have a device that protects against thermal expansion. In fact, protection against thermal expansion is required when the appliance has a check valve. This prevents backflow and reduces the pressure in the equipment.

To ensure protection against thermal expansion, it’s important to measure the air pressure from inside the tank before installation.

Here’s the formula:

Here’s the meaning of each abbreviation:

Pa : The level of air pressure the tank should have
Ps : The static pressure at the water inlet of the potable water supply system
: Difference of height between the water inlet and the tank
: Density of water measured at the initial temperature [cold water]
144 : Conversion factor

It’s also important to keep in mind that the air pressure needs to be adjusted before installing the tank since the weight of the water on the membrane may alter the measurement.

To prevent the risks of excessive pressure, you should call upon certified experts. They’ll know how to guide you to prevent possible hazards. In fact, plumbers will help ensure compliance with Quebec standards and they have the necessary qualifications to check the existing plumbing system. They can also safely install a new water heater. Finally, their expertise will allow you to meet the requirements of various standards and upgrade any type of plumbing system.