Water tanks are essential for many homes, ensuring a steady water supply. However, a common issue is an overflowing tank, which can lead to significant problems. This post explores the common causes of this issue and how to address it, providing homeowners with a practical guide.
Understanding Water Tank Controls
Inside every water tank, a mechanism controls the water level, turning the water flow on to fill the tank and off when full. Two common types of devices are used:
- Ball Valves: These have been around for a long time and are known for their simplicity and reliability. A hollow ball, often made of plastic, is connected to a brass rod that floats on the water’s surface. When the water level drops, the ball also falls, opening a valve that allows more water into the tank. This system is directly connected to a water pump; as soon as the valve opens, the pump starts to fill the tank until the ball rises again, shutting off the valve. Ball valves operate on a single water level, meaning the tank is always kept full, and the pump runs every time you use water.
- Float Valves: These are more advanced, operating on a high and low water level. The tank fills to the high level, allowing water to be used until it reaches the lower level, at which point the tank starts refilling. This is achieved with an electric float valve that controls the water pump. When the water level drops to the low point, the valve activates the pump to fill the tank until the high water level is reached, and the pump is switched off.
Why Water Tanks Overflow
The most frequent culprit for an overflowing tank is a malfunctioning float valve. Here’s how they typically work and what can go wrong:
- Float Valve Mechanism: An electrical switch at the top of the tank is activated by a vertical cord with two floats attached. The floats are set at the high and low water levels, and the weight of both floats together activates the switch. The floats are plastic cylinders that can be adjusted by adding or removing water to achieve the correct weight. When the water reaches the low level, the weight of both floats triggers the switch to turn the pump on. Once the water reaches the high level, the weight is reduced to turn off the switch and therefore the pump.
- Failure Mode: Float valves often fail in the ON position because water leaks into one of the floats, making it too heavy to float. This prevents the switch from deactivating, causing the pump to keep running and the tank to overflow. The heights of the floats should be adjusted to maximize the range of water level between high and low. This will reduce how often the pump turns on and off, thus minimizing wear.
Troubleshooting Overflowing Water Tanks
- Immediate Action: If your tank is overflowing, the first step is to switch off or unplug the water pump. Then, call a professional to fix the issue, ideally during daylight hours. If you run out of water, you can briefly turn the pump back on for a short time.
- Float Valve Issues: Problems with the float valve are common, and these can be difficult to access, making them potentially dangerous to fix on your own.
- Potential Damage: An overflowing tank can cause significant damage, especially if the tank is in the roof space, leading to water damage on ceilings, particularly those made from gypsum.
Important Safety Considerations
- Electrical Safety: Avoid having electrical circuits installed under water tank towers, as this can be very dangerous in the event of a leak. Make sure to check the electrical wiring situation and move it if need be.
By understanding how water tank controls work and what causes them to fail, homeowners can take steps to prevent and address overflow issues, protecting their homes from potential damage.
