Boilers should have mixing valves installed

In some places, it’s not uncommon for domestic water to be heated by a coil on a gas- or oil-fired boiler. When a hot-water faucet is turned on, the coil furnishes hot water. The danger is that this hot water can be unbelievably hot.

“Under the latest building codes, a mixing valve is required on the system to keep the domestic hot water from being so hot,” says Ed Schoen of Prestige Heating Service in Massapequa, N.Y. “But there are many older boilers in service that do not have this valve.”

Schoen says many boilers also might have a manual mixing valve, but these are not reliable. Installing an automatic version can run $250 to $350 and will prevent scalding tap water.

Check with a plumber or oil-heat technician the next time your boiler is being serviced.