Why Do Hot Water Taps Always Lose Pressure?
Have you ever turned on your hot water tap and noticed that the stream of water gradually slows down to a trickle? This phenomenon can be quite frustrating, but it's a common issue that often has a simple explanation. Understanding the reasons behind this can help you address the problem and restore the desired pressure in your hot water tap.
Common Reasons for Reduced Hot Water Pressure
1. Pipe Scaling
Over time, mineral deposits can accumulate inside the pipes, especially in areas with hard water. These deposits can reduce the diameter of the pipes, leading to decreased water flow and pressure. This buildup is known as scaling, and it can significantly impact the performance of your hot water taps.
2. Water Heater Issues
Problems with your water heater, such as sediment buildup at the bottom of the tank, can restrict water flow. If the heater is not functioning optimally, it can also affect the pressure of the hot water. Sediment can clog or narrow the water passages, limiting the amount of water that can flow through the system efficiently.
3. Pipe Size and Configuration
When the pipes supplying the hot water are too small, or have bends and turns, they can restrict flow. This can lead to lower pressure at the tap, especially if the water heater is located far from the point of use. Ensuring that your hot water piping system is properly sized and laid out can help maintain consistent pressure throughout your home.
4. Pressure Regulator Problems
Pressure regulators, which control the water pressure in the plumbing system, can sometimes malfunction or be incorrectly set. If the pressure regulator is not working as intended, it can affect the hot water supply, causing reduced pressure in your taps. Regular maintenance and inspection of the pressure regulator are essential to prevent such issues.
5. Valves and Fixtures
Clogged or partially closed valves or issues with the faucet itself, such as aerators that are dirty or clogged, can also contribute to reduced pressure. Aerators at the end of your taps help control water flow, but they can accumulate contaminants over time, leading to restricted flow and decreased pressure.
6. Demand on the System
Using multiple hot water taps simultaneously or having other appliances like dishwashers or washing machines drawing hot water can lead to a temporary drop in pressure. This is particularly noticeable when multiple fixtures are in use at the same time, as the demand on the hot water system can exceed its capacity.
Understanding the Phenomenon
Temperature-Induced Changes
You turn on the tap just slightly, and as the water warms up, the stream slows to a trickle. This can be due to temperature-induced changes in the stem of the faucet. When you first turn the water on, the cooler stem contracts. As the water starts to heat up, the stem expands, closing the gap between the washer and the seat. This creates a restriction that slows the flow of water. This effect is usually more pronounced in taps that rely on washers to control the flow.
Pressure Reducing Valves
Sometimes, a pressure reducing valve is fitted to the cold water entry to the hot water system. When the hot tap is first opened, the water rushes out, and as the valve restricts the flow, the pressure gradually decreases. Modern hot water systems often have a thermostatic mixing valve, which helps to prevent burns by adjusting the temperature of the water to a safe level. This valve can also cause a temporary drop in pressure when it starts to do its job.
Thermal Expansion in Faucet Stems
When the hot water tap is first opened, cold water enters the pipe and then hot water arrives. The expansion of the hot water in the stem of the tap can cause it to lengthen, further restricting the flow of water. This can be another factor contributing to reduced water pressure.
If you're experiencing persistent low pressure in your hot water taps, it may be worthwhile to have a plumber assess the situation. Identifying and resolving the underlying issue can help you restore a consistent and reliable hot water supply.