Ouch! Is the water coming from your hot water system too hot? Has reduced water flow? Maybe it’s a classic case of a tempering valve not working properly. 

As we know, the hot water supply is maintained at 60°C to prevent harmful bacteria growth, like Legionella. But this temperature can cause scalding injuries or third-degree burns, even with little exposure. 

No one wants that kind of hot on their skin. Consequently, it’s mandated in every state that hot water systems have tempering or mixing valves. These devices regulate water temperature as it flows from hot and cold water sources, ensuring that the water delivered to fixtures like faucets and showers is at a safe and consistent temperature (not exceeding 50°C).

But like any device, tempering valves sometimes fail, compromising your safety and shower experience. Hence, it’s best to know the signs of a tempering valve not working as it should and before scalding hot water welcomes you.

How to tell if a mix valve is broken?

If you suspect that your mixing valve is broken or malfunctioning, here are some signs and steps to help you determine if it needs repair or replacement:

1. Fluctuating water temperature

Hot, cold, lukewarm — all in just a few seconds?

If you experience inconsistent water temperatures, with sudden fluctuations from hot to cold or vice versa, while using a single faucet or shower, it may indicate a problem with the mixing valve.

2. Too cold or too hot

When you’re only getting water at extreme temperatures, it’s a clear sign that something’s broken with your tempering valve or it’s losing precision. This means that the valve isn’t mixing the water well or not mixing at all. So, be careful when you get cold water, as the next stream could burn you.

3. Leakages and dripping hot tap

Check around the mixing valve for any visible leaks or drips. Leaking water can indicate a seal or internal component failure in the valve. 

4. Reduced water flow

A broken tempering valve can sometimes restrict the flow of hot or cold water from the supply lines, which reduces the overall water pressure in the system. This could be due to the following reasons:

• Mineral build-up: Over time, sediment and mineral deposits can accumulate inside the tempering valve, obstructing its internal components and reducing water flow.

• Obstruction: Malfunctioning tempering valves with damaged internal components can cause blockages, limiting water flow and reducing pressure.

• Leakages: Leaking water from the valve reduces overall water availability in the plumbing system, leading to fixture water pressure reduction.

• Valve closure: Certain tempering valves shut off completely in case a malfunction occurs to prevent scalding or exposure to extremely hot water.

5. Unusual creaking and other noises

"Cre-e-ak." Hearing strange noises when you adjust the temperature? This could mean tempering valve broken internal parts or debris blockage, leading to water flow turbulence. 

Some valves also close abruptly in case of a malfunction, further contributing to the noise. These sounds, sound the signal for a professional plumber to inspect the setup to ensure safe hot water delivery.

Observed one or more of these signs? it's likely that your tempering valve is broken. In such cases, consider contacting local plumbers to assess the situation and decide whether a shower tempering valve repair or replacement is necessary. 

Should I have my tempering valves replaced?

Like in most devices, the decision to replace your tempering valves depends on their condition and performance. Specifically, you can determine if your tempering valve is broken beyond repair and due for replacement by considering the following:

• Age: As time passes, valves may experience wear and tear, and if they are considerably aged, replacing them often leads to better hot water system performance.

• Safety: If your current tempering valves are not effectively sustaining a consistent water temperature, it becomes essential to replace them to avert potential scalding accidents, and in that case, you’ll definitely need help with a first aid kit and potentially medical treatment depending on the severity of the burn.

• Laws and regulations: Some building codes and regulations may require the replacement of older or non-compliant tempering valves to meet safety standards. 

But even if you’ve done your evaluation, it's still best to consult a professional plumber who can properly assess your plumbing system or tempering valve condition and provide guidance on whether replacement is necessary.

When should I replace my mixing valve?

Tempering valves lose their precision and collect sediments over time, hindering their ability to effectively control and regulate temperature. If left unattended, this compromise exposes us, especially children and elderlies, to scalding injuries. 

Therefore, experts recommend that tempering valves should be replaced every 5 years, even if these have a lifespan of 5-10 years. This way, you can account for external factors contributing to the valves’ deterioration. 

It’s also best to have the valves checked annually to detect underlying issues, even if it’s still within the five-year limit. 

Do I need a professional?

“It’s just a valve.” No. It’s a valve sitting between you and the hot water supply. If that tempering valve malfunctions and your DIY solution fails, there’s no turning back after the stream of hot water hits your skin and leaves lasting burn scars. 

Always seek a professional plumber’s assistance. They know these valves and systems better and have the right tools and protective gear. Who knows, your plumbing system might even have more issues that only a licensed plumber like Kevin Szabo Jr Plumbing can detect and fix.