Have you ever wondered why the water heater in your home has another small tank hanging off the side?
This is a common question asked to Watch Dogs Home Inspectors Utah by home buyers and sellers during the walk through. Our Inspectors explain that an expansion tank installed on the water supply pipe to the water heater is designed to handle the thermal expansion of water as it heats up in the water heater, preventing excessive water pressure. If water pressure gets to high it can damage valves in plumbing fixtures, joints in supply pipes and the water heater itself.
Thermal expansion always occurs in water heaters. As water expands it is heated, and this happens several times a day. Because water cannot be compressed, it will increase in pressure if it doesn’t have room to expand as it is heated. In the past, the expanding water in water heaters would push some water back out of the house – into the public water main, which could absorb the pressure.
But that way of relieving pressure doesn’t work anymore. The reason is check valves. A check valve is a one-way valve that prevents back flow of water, keeping it from flowing in the wrong direction. Check valves are installed on all connections to the public water supply now. Watch Dogs Home Inspectors Salt Lake City always explains the purpose is to keep water from flowing back out of the house through the service pipe.
This prevents contamination that might occur in the plumbing within a house or business from contaminating the public water supply in the street. Space for expansion in the system is necessary because water pressure builds rapidly in the house as the water heater heats up.
Expansion tank to the rescue. The expansion tank contains air, which is highly compressible. Expanding water from the water heater can flow into the expansion tank, where the air compresses, making room for the increased volume of water, and making sure water pressure in the system doesn’t increase significantly.
If you’ve noticed that washers in plumbing fixtures seem to wear out rapidly, or if water drips intermittently from the relief valve on the water heater, you may need to add an expansion tank.
Protect your investment and the safety of your home by hiring a professional home inspector from Watch Dogs Home Inspectors in Utah.