A temperature pressure relief valve is installed on storage water heaters on the side towards the top of the heater. This valve protects the water heater, by relieving pressure and allowing water to escape, as the water inside the cylinder expands due to heating.
During normal water heater operation, a small volume of water may discharge from the valve during the heating cycle. This is normal operation and safe. However, if your water heater discharges more than a bucket full of water in 24 hours, there may be another problem
Issue: Continuous water dribbling from the pressure valve
A continuous dribble may indicate a small particle of foreign matter may be caught in the valve. Try gently raising the easing lever on the relief valve for a few seconds. This may dislodge any particles and clear the fault. Release the lever gently
Issue: Steady flow for long periods (often at night)
This may indicate the mains water pressure sometimes rises above the designed pressure of the relief valve. Ask your installing plumber to fit a pressure limiting valve.
Warning: Never replace the relief valve with one of a higher pressure rating.
Issue : Heavy flows of hot water until water heater is cold – then stops until water reheats.
An electric water heater must be switched off at the switchboard.
If you have a gas water heater, the gas control must be turned off using the knob on top of the gas control thermostat