As you know the hot tankless water heater uses either an electric heating element or a gas burner to heat cold water and make it hot. When water is heated it expands, and this known as ‘thermal expansion’ which can give pressure and damage to the pipe. That is, because of Thermal Expansion, a regular hot water heater creates about an extra half gallon of water in the pipes. The problem is, if the extra water doesn't have an outlet it increases the pressure in the pipes.

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This will lead to many problems such as, damage to the T and P relief valve and the resulting drip, running toilets etc.

The remedy is to install a Thermal Expansion, which is a small tank with an air bladder inside that is installed in the cold water pipe near the tankless water heater. When the tankless water heater starts heating, the extra water due to thermal expansion is forced into the tank and compresses the air bladder. As the water cools, or a faucet is opened, the bladder pushes the extra water back out of the tank,

Water Heater is an expensive device and its key plumbing system is always vulnerable to heating and pressure. It is always wise to take precaution against damage and loss. Installing a thermal expansion tank is a better idea to solve high pressure to the piping system and the resultant damages. And, installing a Thermal Expansion Tank is easy and simple. What you need is a few basic tools and a little knowledge about the system.