Water Heaters and Thermal Expansion: Does Your Water Heater Need a Thermal Expansion Tank?

Water Heaters: Friend or Foe?run.  This valve is designed to release pressure if
Your Water Heater is one of the most expensiveit gets up to 150 psi.  The problem is that it's
and important parts of your plumbing system. really a safety valve and isn't designed to open
Without your water heater life just wouldn't beand close a lot. Too much could cause it to fail.
the same.  Imagine cold showers every day! 
But did you know that your water heater couldThermal Expansion Can Cause Running Toilets
be causing a problem in your pipes?Another symptom of thermal expansion problems
Hot Water Expandsis a toilet that keeps running or kicking on from
Hot water heaters do their job by using either antime to time.  This is caused by the excess
electric heating element or a gas burner to heatpressure overcoming the float on the fill valve,
cold water and make it hot.  The problem is thatallowing water to run into the tank.  Over time
water expands when it is heated.  This is calledthis can cause the fill valve to stop working and
"Thermal Expansion".make it run constantly.
A 40 Gallon Water Heater Can Cause An Extra
Half GallonA Thermal Expansion Tank At The Water Heater
Due to Thermal Expansion, a regular 40 gallon hotWill Solve These Problems
water heater creates about an extra half gallon ofIf you are experiencing either of these problems,
water in the pipes while heating water from 70or if you are just replacing your water heater, it
degrees to 120 degrees.  If the extra wateris a good idea to install a Thermal Expansion
doesn't have anywhere to go it causes theTank.  This is a small tank with an air bladder
pressure in the pipes to go up, sometimes wayinside that is installed in the cold water pipe near
up.the water heater.  When the water heater
comes on and starts heating, the extra water
Water Heater Plus Closed System Equals Athat is created is forced into the tank and
Problemcompresses the air bladder.  As the water cools,
If you have a "Closed System", meaning there isor a faucet is opened, the bladder pushes the
a check valve or Backflow Preventer" on theextra water back out of the tank,
incoming water line, the extra water volumeA Fairly Simple Job
caused by thermal expansion has nowhere toInstalling a Thermal Expansion Tank at your water
go.  This means that the pressure in your pipesheater is a fairly simple job.  You just need to
can get too high, possibly causing problems.turn the main water off, install a tee  and female
Too Much Pressure Is Badadapter in the cold water pipe near the water
If your pressure gets too high because ofheater and then screw the Expansion Tank into
thermal expansion it can cause several problems. the adapter.  A few basic tools and a little
One of the main issues is that your T and P Reliefknowledge and you can eliminate thermal
Valve on the water heater can start to drip orexpansion from your piping system.