What does an expansion tank do?
Water expands when it is heated. In an open system the extra volume pushes back out toward the street. Many homes have a pressure regulator or a backflow device on the water line, and those act like a one-way gate. The expanding water has nowhere to go, so pressure in the house climbs every time the heater fires. An expansion tank gives that water a place to go: an air cushion inside the tank compresses and takes up the extra.
How do I know if I need one?
- The relief valve on the water heater drips or discharges now and then.
- Faucets spit or surge briefly when first opened.
- Pipes bang, or toilet fill valves wear out quickly.
- You have a pressure regulator or backflow device and no expansion tank.
- You are getting a new water heater. Current plumbing code calls for expansion control on closed systems.
Do expansion tanks wear out?
Yes. The rubber bladder inside eventually fails and the tank fills with water. Then it does nothing. A waterlogged tank is heavy and feels cold and solid all over. They are replaced, not repaired.
How is one installed?
We check your water pressure first. If it is too high, the pressure regulator is dealt with too, since an expansion tank cannot make up for a failed regulator. Then we fit a tank sized for your water heater on the cold line, support it properly, set its air charge to match your pressure, and test. It is usually done in one visit.
Is it part of a water heater replacement?
When we replace a water heater, we check whether the home needs expansion control and include it in the estimate when it does.
Who is Friendly Services?
A family-owned plumbing company with over 20 years in Hayward. License CSLB #1156315 (C-36 plumbing), $1M general liability cover and workers' comp. Our own work has a five-year workmanship warranty, and we have 100+ five-star reviews online.