Most geysers have a small pipe that comes out through the wall or roof and ends outside, often above a drain. If water drips or runs from it, the geyser is releasing water through one of its safety valves. A little dripping can be normal. A steady stream is not.
The valves and drains that empty outside
| Valve | What it does | When it releases water |
|---|---|---|
| Pressure control valve | Keeps mains pressure to the geyser at a safe level | Occasionally when mains pressure spikes |
| Temperature and pressure (T&P) valve | Last line of defence if the geyser gets too hot or the pressure too high | Only when something is wrong |
| Vacuum breakers / drip tray drain | Protect the cylinder and catch leaks | When the tank drains or leaks |
As water heats it expands, so a few drops while the geyser is heating can be normal on some installations.
When it's a problem
- Water runs constantly, day and night: usually a worn pressure control valve or T&P valve that no longer seals. You're paying for water, and for electricity to heat it.
- Hot water or steam comes out: the thermostat may have failed and the geyser is overheating. Switch the geyser off at the DB board and call a plumber now.
- Water drips from the ceiling or the drip tray overflows: the geyser or a fitting may be leaking. See burst geyser: what to do.
What you can safely do
- Switch the geyser off at its breaker in the DB board.
- If water is running fast or the ceiling is wet, close the cold water supply to the geyser (or the main stopcock: see how to shut off your water).
- Don't block, cap or tie up the overflow pipe. It exists to stop the geyser from bursting.
- Take a short video of the pipe so the plumber can see how much water is coming out.
What a plumber will usually do
Replacing a pressure control valve or T&P valve is a common, fairly quick job, but valves and geysers must be installed by a registered plumber and should comply with SANS 10254. If the geyser is old, they may recommend replacing it. Your insurer may want a plumber's report if there is water damage.
Compare geyser repair and replacement in Benoni or see plumber prices in Benoni. If your geyser isn't heating at all, see geyser not heating.