Every home has a water heater. These units are often taken for granted and neglected. Hot water heaters are in fact boilers. The burner or electrical heating element is adding energy to the water. Although a majority of water heaters are exempt from the Safety Codes Act based on their heating surface or diameter, the potential for a major accident is there because of the amount of stored energy involved.

With the recent failure of a domestic water heater, which left two people homeless but luckily unharmed, it is time to remind everyone who has a water heater that they should test the water heater s pressure relief valve (PRV). This procedure is simple and could save life!

The PRV is usually found on the side of the tank, near the top, on a gas fired water heater and on the top of the tank or in the hot water outlet on an electric water heater. About once a year, test the pressure relief valve by opening the valve manually using the lifting lever on the PRV. Ensure that no one will be scalded by the hot water released from the PRV. If the PRV does not discharge water when you open it, then the PRV must be replaced immediately. If the PRV does not re-close tightly, try opening it again to flush out any sediment. If the PRV continues to leak, it must be replaced. You must not plug the PRV and should not operate the heater with a leaking PRV for a long period of time.

If you are replacing the PRV, shut off the water to the heater and de-pressure the heater. Ensure that the replacement PRV is of the appropriate type, capacity and set pressure for the water heater. Check the manufacturer s instructions on maintenance of pressure relief valves. The PRV is for your protection. In the case of over pressure, this valve is to automatically release the pressure preventing the tank from exploding.

The manufacturer's instructions are a good source of information for safe operation, to extend the life and to maintain efficiency of your heater.

First published January 2006