hot water safety valve shower in stock

At this time of year, hot showers are valued and many homeowners change the temperature of their hot water heater to reflect their desire for warmth. Still, some homeowners find it difficult to find the perfect equilibrium in their hot water heater, and the result is a shower or bath that runs too hot or too cold. Other baths and showers simply run too hot or cold, regardless of the hot water heater temperature. There are several options for solving this problem.

It’s possible your shower runs hot or cold because you just haven’t found the right temperature setting for your hot water heater. In general, 120 degrees Fahrenheit is considered to be the magic number for hot water heaters. This temperature is warm enough to stem the growth of bacteria in the hot water heater, and also warm enough to reach a perfect hot temperature in your shower.

In homes with young children or elderly occupants, 120 degrees may be too hot. Homeowners living with young children or elderly relatives should consult with a physician before changing the temperature on the water heater.

On some hot water heaters, adjusting the temperature is as easy as turning a dial. However, on other hot water heaters the temperature setting is hidden behind a panel. Follow these steps to remove the panel and adjust the temperature in your hot water heater to a toasty 120 degrees.

Use the phillips head screwdriver to remove the panel covering the temperature dial on the water heater. This panel cover will likely be marked to indicate that it covers the temperature dial.

The mixture of hot water and cold water available in a shower or tub can be adjusted at the shower valve stem, the part found under the faucet. The exact process for adjusting the hot and cold water will depend on the type of faucet in your shower or tub, but the general idea is as follows:

Take off the metal cover beneath the handle, exposing the valve stem. You’ll see a plastic part around the valve stem. This plastic part is known as the “rotational stop limit,” (RSL). This is the part of the shower that controls the mixture of hot and cold water coming out of the faucets. The directional controls will probably be noted on the RSL, but in general a counter-clockwise turn will release more hot water, and a clockwise turn will release less hot water. To turn the RSL, you may have to pull out the RSL cover to reveal the teeth that hold the RSL in place.

In addition to the YouTube videos above, there are several online resources that may help you adjust the hot and cold water in your shower or tub. Here are a few:

Handyman How To: This online resource includes a very useful step-by-step tutorial with a helpful picture and an informative section about water temperatures as they relate to bacteria and scalding danger.

Apartment Therapy: This website has a very lengthy explanation about the best temperature for water heaters and how to prevent children from being scalded.

When in doubt, you can always contact a plumber to help you adjust your shower’s hot and cold settings. Residents of the Pittsburgh area can call Terry’s Plumbing. We’re happy to make any necessary adjustments to your faucets or water heater.

However, that satisfaction can go away quickly when you crank the shower faucet all the way over, and you can’t quite get the water temperature as high as you would like it. This article will discuss how to increase your shower’s water temperature by adjusting the Delta shower valve. Although this article specifically focuses on the Delta a similar process can be followed on Moen, Koehler, or American Standard brands.

You can increase the water temperature for your shower valve by removing the handle with an Allen wrench and then using a Phillips head screwdriver to remove the limiter lock. Then pull the plastic limiter off and rotate it slightly clockwise to increase the hottest water setting. Be cautious and test the water before and after to prevent potential scalding temperatures!

Throughout this article, we will discuss the different aspects of the temperature controls that shower valves provide and the variations you may run into while modifying your own. If you are a visual learner, check out my YouTube channel for video instructions for the whole process.

Shower faucet valves are mixing valves with pipe fittings that sit behind the wall of your shower. Every shower faucet valve works on the same principle of combining hot and cold water to create a consistently warm shower experience without temperature fluctuations.  These valves are also called “mixing valves” since they are responsible for mixing the cold and hot water lines into the desired water temperature as set by the handle.

Regardless of what style of trim your shower has, the valve should function universally with two input pipes, one for hot water and one for cold. There should be two output pipes, one for the showerhead and one for the bathtub spout.

As a prominent manufacturer, Delta is one of the best at maintaining the same design for multiple years and identified by a valve “series.” It is vital to remember that your shower faucet’s visual parts are referred to as the trim kit. While those may differ depending on the style you get, the inner workings are often similar depending on the age of your Delta valve.  If you talk to a licensed plumber they would call this universal mixing valve the “rough-in valve.”

One subscriber, Gheorghe, asked me what size Allen wrench I used to remove the shower handle. This is an excellent question because this is where sizes may differ slightly. I used a 7/64″ Allen wrench, but a 2.5 mm would also do the trick. While the Delta shower valves are universal and always use the same sizing for the actual device, the trim kits may require slightly different sizes.

Many showers don’t get as hot as people would like because the limiter is set to a lower temperature by default. This is to prevent the possibility of people (especially children) from injuring themselves with scalding water. This functionality is perfect for keeping people safe.

Delta manufactures their valves with an easily accessible limiter for the exact purpose of making these sorts of changes. This is so that you can enjoy a shower at the temperature you want while keeping things safe for every person in your house. Part of why I created my YouTube channel and website is to inform people about these types of repairs that can be quickly done at home with a bit of know-how.

Modifying the limiter to get a higher water temperature is not a complicated process to follow. Just keep these instructions close at hand, and you’ll have nice hot showers in no time.

The best way to ensure that you get your shower to the appropriate temperature is to test the water with a thermometer. In my video, I measured it beforehand, and it came to around 110 degrees Fahrenheit. Knowing what temperature you start with will help you find the perfect setting.

Remove the actual handle from your shower faucet. This step is where you may experience some deviation from this guide depending on the kind of trim kit you have in addition to the Delta valve series. If your trim kit has a handle like mine, there should be an Allen wrench screw on the faucet’s underside. If your shower handle uses a transparent knob like the kind found in older trim kits, you may need to use a flat head screwdriver for popping off the front screw cover.

Once you’ve removed the handle through either method, you should then see a screw head protruding from the valve itself, with a white plastic component just behind it. Use your Phillips screwdriver to remove the silver adapter and lay it to the side.

At this point, you should see the small plastic circular plate that limits the movement of the valve and prevents it from getting too hot. Remove the limiter, and you should see the threads or splines, as one subscriber pointed out.

Rotate the limiter clockwise and place it back in its spot. The splines should line up with the grooves on the valve, and it should move into place without much struggle. Note that it will not rotate too far as the valve has an absolute hard limit that you can’t go beyond due to safety concerns.

Before replacing the handle, you should take this opportunity to measure the temperature of your water again. In my video, I aimed to reach 120 degrees Fahrenheit, a correct spot to aim for but use your own discretion.

Lastly, replace the shower valve handle using the Allan wrench, or if it has a cover, pop it back into place, and you’re done! Remember to advise anyone who might be using the shower that it may be hotter than before and to be careful when setting the temperature to avoid scalding themselves.

You may encounter a couple of challenges while you are adjusting your Delta shower valve water temperature. We have compiled answers for some of the common issues you might encounter with our subscribers’ help. If you find yourself with any questions of your own, please leave a comment on the video, and I will do my best to help!

A couple of subscribers mentioned that they were unable to remove the handle from their faucet. This issue can be due to a couple of different reasons: a buildup of mineral deposits that usually show up as a greenish material on the inside of the handle due to hard water or stripped threads inside the socket.

If you have excessively hard water in your area, the best way to work around this issue is by soaking the part of the handle where it connects to the shower (including the internal components) in vinegar. This will break down the mineral deposits. After letting it soak for a while, you should be able to remove the handle easily and continue with your temperature adjustment.

If your valve or handle has stripped threads preventing you from loosening it, you may need to replace either your trim kit or the valve itself. Depending on which components you need to replace, this can cost anywhere from $100-$500, depending on where you live and the costs of hiring a plumber.

Another subscriber, Faith, encountered an issue where their shower handle is missing the grey attachment piece that needs to be removed before accessing the limiter. This piece is an adapter that functions as a mounting piece for your shower’s handle to attach to the valve stem. If this component is missing, it can contribute to a lukewarm water problem and should be easily replaceable by going to your local hardware store.

It is also important to recognise that you can follow the steps to remove the handle and adjust your shower temperature without turning off your water supply. However, if you need to replace any part of the valve itself, you will need to shut off your water for the duration of that replacement. If you are not an experienced plumber, it is strongly recommended that you hire one to replace a broken valve. It can be a costly procedure to do incorrectly.

As you can see, adjusting the limiter on your Delta shower valve is an easy process once you understand what to look for. Nobody should have to deal with lukewarm showers when it’s this easy to make the adjustment. If you find yourself unhappy with the temperature of your shower, get a jump on it and save yourself from that kind of disappointment. Remember to check out my YouTube channel for more tips and tricks for everyday home repairs and updates!

You’re happily swabbing yourself down in the shower. Suddenly someone flushes a toilet, the water grows hotter than a Habanero chili and you’re howling for mercy and swiping at the shower control from a safe corner.

Aside from strengthening your vocabulary and your reaction time, such incidents serve mainly as a temporary irritant. But, according to experts, several thousand people each year suffer severe scalds and thermal shock injuries caused by instantaneous water temperature changes while they are bathing.

While exact numbers are hard to come by, the National Safe Kids Campaign, a program headed by former U.S. Surgeon General C. Everett Koop, estimates that 5,000 children are scalded in the bathtub each year. In general, “hot water burns are the single most common way for a child to be burned,” says Dr. Bruce Achauer, director of the UCI Burn Center and chairman of the Burn Prevention Committee of the American Burn Assn.

And, when there’s a sudden change in water temperature, the individual reacts instinctively to escape the water. Such shock reactions lead to slipping and knocking body parts against the shower, resulting in further injuries.

Such unnecessary injuries should tail away in the next five to 10 years. Anti-scald valves are making their way into the residential plumbing codes across the country.

“The codes have been passed at the level affecting single-family new construction and will be put into effect in the next 12 months,” says Reed Fry, director of marketing for the Rohl Corp. in Costa Mesa. Rohl is the importing arm for KWC bathroom and kitchen faucets; its KWCdomo line protects against scalds and maintains constant temperatures despite water supply fluctuations.

Within two years, the anti-scald valves will also heavily impact the remodeling market as municipal codes incorporate anti-scald requirements, Fry says.

The simplest way to cut the risk of scalding in the shower is to set your water heater to a temperature of 120 degrees or lower. A 140-degree setting, not at all uncommon, can produce a water flow that will severely burn a child in three seconds or an adult in five seconds.

People usually bathe in water between 96 and 102 degrees, notes Joel Kleinberg, a Los Angeles attorney and board member of the American Scald Burn Foundation who has handled liability cases resulting from scalding.

The anti-scald valve has been around for 50 years or more, but for a variety of reasons it never caught on in residential construction. They are more expensive ($20 to $25) than the low-end residential two-handle lines and plumbing codes did not require them.

Manufacturers of two-handle faucets did not have the technology to produce anti-scald valves, so they opposed such codes. Contractors did not spend much time telling buyers what options were available behind the shower face plate. And for plumbers, the valves meant extra work with unfamiliar items.

But consumers are becoming more aware of this feature from a comfort and a safety standpoint, says John Schott, senior product manager for faucets--including the Rite-Temp line of anti-scald valves--at the Kohler Co. in Kohler, Wis.

Anti-scald valves of all types now account for only 20% to 25% of the total market, estimates John Diohep, vice president of sales for Symmons Industries in Braintree, Mass. More than 30 years ago, Symmons was the first company to market a fully pressure-balanced anti-scald valve.

There are two schools of thought on anti-scald valve design. These single-handle valves use pressure and/or temperature balancing techniques to quell large temperature changes even as they get started. While code requirements vary, most establish that the valve keeps the temperature within three degrees plus or minus of the original setting, to prevent thermal shock reactions.

Pressure-balanced valves respond to pressure disturbances in the lines, Diohep explains. A stainless steel piston slides toward the higher pressure, reducing hot water flow if the cold water flow drops, and vice versa.

Thermostatic valves have bimetallic valves that expand as the temperature increases, reducing the hot water flow. The more expensive combination thermostatic/pressure-balanced valves, such as those made by Leonard Valve, control both temperature and pressure, adjusting for the pressure indirectly. Such a combination provides an extra level of protection, says Greg Wilcox, vice president at Leonard Valve in Cranston, R.I.

The pressure-balanced valves reportedly respond more quickly to temperature changes, reacting in less than a second to a pressure change. The thermostatic valves respond to a temperature change in one to two seconds. However, the pressure-balanced valves require the temperature limit be set by the plumber on site. The limits on the thermostatic valves can be preset.

The anti-scald valves of both types have adjustable limit stops that prevent incoming water from exceeding a set temperature. Some units have an override button that can be pushed to get hotter water, but most limit stops use a screw adjustment.

You’re enjoying a relaxing shower, charging up for the day or winding down for the night, when someone flushes a toilet. For the next 30 seconds (which feels like 30 minutes), you’re in the midst of a scalding hot flow of water as the toilet tank refills.

In other cases, someone might run hot water as they fill the washing machine, and there you stand, submerged in cold water, the relaxing shower you had envisioned ruined.

Aside from inconvenience and shock, a quick change in water temperature can lead to significant injuries, especially for children and the elderly. An extreme change in water temperature can startle the person showering, leading them to slip and fall. Scalding hot water can also cause burns, especially for those with sensitive skin.

In a shower, hot and cold water flow together in a ratio that is determined by turning the shower faucet handles and adjusting their respective rates. Some faucets have one handle that controls both temperatures at the same time while others have two handles, one for hot water and one for cold water.

Unfortunately, in a house with multiple people, others may need to use the water as well. So when a toilet is flushed, for instance, cold water is diverted from the shower to fill the toilet tank, creating a scalding hot shower since only hot water is available at that moment. In contrast, if someone uses hot water, to wash dishes or do a load of laundry, hot water is diverted, and the person in the shower is stuck under a stream of icy water.

There are two types of regulating valves to ensure a consistent temperature for the duration of a shower. Each has its benefits, but one definitely comes out on top when it comes to delivering the perfect shower experience.

Pressure balance shower valves do just what their name implies. They balance the water pressure to compensate for a lack of hot or cold water, maintaining a stable temperature. Unfortunately, this style of shower valve only balances the pressure in order to maintain a consistent temperature.

The pressure of the water from the shower head can vary greatly as the temperature is stabilized. This is especially noticeable in low-flow shower heads or a shower setup with more than one shower head. The reduction in pressure, while not necessarily as shocking as a change in temperature, can still disrupt the shower experience.

Pressure balanced shower valves utilize changes in water pressure to balance the shower temperature, but thermostatic shower valves actually control the water temperature. Thermostatic shower valves have a distinct advantage since the temperature will remain consistent throughout the duration of your shower.

Thermostatic shower valves allow you to pre-set the water temperature, ensuring that the water won’t become hotter or colder than your desired setting while still allowing each person to manually adjust the water temperature. Pre-selecting a water temperature also conserves water, making it an environmentally-friendly option. The high flow rates of a thermostatic shower valve also accommodate a variety of shower applications.

This two-handle system adds a sleek touch in a shower design. The easy-grip lever handle and hexagonal handle with protrusions make turning the shower on and off and adjusting the shower temperature easy.

The H-Line 115 wall mounted mini shower valve trim kit is compatible with three thermostatic shower valves (SS-TH60, SS-TH70, or SS-TH80). Each of these thermostatic valves includes integral stops and check valves, and you can choose from a 1-, 2- or 3-way diverter. All three choices include volume control.

This shower kit offers an earthy feel with a sleek look. The simple look allows for easy use when changing water temperature and turning on and off the shower while remaining a great option for any shower design.

This Elan Vital 38 Mini has built-in control while appearing modern and sleek. This petite trim kit is great for small showers while still offering a modish look that never goes out of style.

Perfect for a luxury shower design, this wall-mounted thermostatic shower trim comes with two built-in controls. Easy-grip lever handles make adjusting the water volume a breeze, and the single temperature control in the center allows you to set the perfect temperature that won’t change throughout the duration of the shower.

This trim kit combines the classy look of a lever handle with an industrial look, making for a unique style great for showers. This style makes it effortless to start and stop your shower, along with adjusting the temperature.

This shower kit gives a classy, nostalgic vibe that will look elegant in any shower. This product makes working the shower a breeze, while still maintaining a polished and clean look to any shower design. This style is available in two marble colors: Ferra White or Cordoba Black Marble.

Ideal for smaller showers and those that desire a streamlined design, this simple lever handle centered in a circular plate adds a stylish element. This trim kit is compatible with the SS-TH500 thermostatic shower valve that allows you to pre-select water temperature and compensates for fluctuations in water pressure which prevents scalding (note that an additional volume control is needed).

No matter your thermostatic shower valve needs, Watermark has a variety of valves and corresponding trim kits that will create the perfect, temperature-controlled shower experience.

I am often asked, “What is a safe hot water temperature for domestic hot water?” If you read the model codes, it states the maximum hot water temperature for a shower or bathtub is 120 degrees Fahrenheit. If you read the warning labels on the side of most water heaters the maximum hot water temperature is 120 degrees Fahrenheit on some labels and 125 degrees Fahrenheit on other labels. The 125 degree limit probably allows for some temperature loss before the hot water gets to the fixtures. Most water heater literature and warning labels mention the availability of thermostatic mixing valves or automatic temperature compensating valves and they recommend their use. If you look at many of the industry standards for shower mixing valves, they state the valves must have limit stops that are adjustable to limit the maximum hot water temperature to 120 degrees Fahrenheit. The testing in the standards gives test criteria for testing the shower valves to these limits.

I have served on the working groups for several plumbing industry standards committees for temperature actuated mixing valves and shower valves and it is generally agreed that 120 degrees is the maximum, safe hot water temperature. I also have served on hot water system design standards committees where the participants had agreed that maximum domestic hot water temperature from plumbing fixtures used for bathing and washing purposes should be 120 degrees Fahrenheit. There were a few exceptions for bidets, sitz baths and whirlpool tubs that had temperatures lower than 120 degrees Fahrenheit for the recommended maximum temperatures to prevent scalding. It also should be noted that some other uses like commercial dishwashers and laundries may need temperatures higher than 120 degrees Fahrenheit. There were two temperatures discussed for each fixture during the design standard meetings. One was the “use temperature” and the other was “the maximum temperature” to prevent scalding.

It’s generally agreed that 120 degrees Fahrenheit is the maximum safe hot water temperature that should be delivered from a fixture. Therefore hot water above 120 degrees Fahrenheit can be considered hazardous. Model codes address this in various code sections.

2009 IPC Section 424.3 — Individual shower valves. Individual shower and tub-shower combination valves shall be balanced-pressure, thermostatic or combination balanced-pressure/thermostatic valves that conform to the requirements of ASSE 1016 or ASME A112.18.1/CSA B125.1 and shall be installed at the point of use. Shower and tub-shower combination valves required by this section shall be equipped with a means to limit the maximum setting of the valve to 120°F (49°C), which shall be field adjusted in accordance with the manufacturer’s instructions. In-line thermostatic valves shall not be utilized for compliance with this section.

The last sentence that states “in-line devices shall not be used for compliance with this section” does not mean in-line devices should not be used, it means the in-line devices will not protect against thermal shock and an automatic temperature or pressure compensating type shower valve conforming to ASSE 1016 must still be used to protect against pressure imbalances between the hot and cold water system which can lead to thermal shock incidents. A properly designed system would have a water heater set at 140 degrees Fahrenheit followed by a master thermostatic mixing valve set at a maximum of 120 degrees Fahrenheit and compensating type shower valves conforming to ASSE 1016 or CSA B125.1 located at each shower. Each shower valve should have the maximum temperature limit stop set to a safe temperature below 120 degrees Fahrenheit.

2009 IPC Section 424.5 — Bathtub and whirlpool bathtub valves. The hot water supplied to bathtubs and whirlpool bathtubs shall be limited to a maximum temperature of 120°F (49°C) by a water-temperature limiting device that conforms to ASSE 1070 or CSA B125.3, except where such protection is otherwise provided by a combination tub/shower valve in accordance with Section 424.3.

2009 IPC Section 424.7 — Temperature-actuated, flow reduction valves for individual fixture fittings. Temperature-actuated, flow reduction devices, where installed for individual fixture fittings, shall conform to ASSE 1062. Such valves shall not be used alone as a substitute for the balanced pressure, thermostatic or combination shower valves required in Section 424.3.

414.5 Limitation of Hot Water in Bathtubs and Whirlpool Bathtubs. The maximum hot water temperature discharging from the bathtub and whirlpool bathtub filler shall be limited to 120ºF (49ºC) by a device that conforms to ASSE 1070 or CSA B125.3. The water heater thermostat shall not be considered a control for meeting this provision.

The maximum hot water temperature discharging from a bidet shall be limited to 110ºF (43ºC) by a device that conforms to ASSE 1070 or CSA B125.3. The water heater thermostat shall not be considered a control for meeting this provision.

Showers and tub-shower combinations in buildings shall be provided with individual control valves of the pressure balance, thermostatic, or combination pressure balance/thermostatic mixing valve type that provide scald and thermal shock protection. These valves shall conform to ASSE 1016 or ASME A112.18.1/CSA B125.1. Gang showers, when supplied with a single temperature-controlled water supply pipe, shall be controlled by a mixing valve that conforms to ASSE 1069. Handle position stops shall be provided on such valves and shall be adjusted per the manufacturer’s instructions to deliver a maximum mixed water setting of 120°F (49°C). The water heater thermostat shall not be considered a suitable control for meeting this provision.

The codes generally agree if there is a hazardous condition or a condition that is unsafe or a nuisance to life, health and property it should be corrected. It is also generally agreed that water above 120 degrees Fahrenheit at fixtures for bathing and washing with a few exceptions for lower temperatures can be considered dangerous and proper precautions should be taken to prevent the hot water from being a scalding hazard by using the proper safety devices.

When I hear about people setting their water heater to 120 degrees Fahrenheit to prevent scalding, I know they have good intentions, but most people do not know you cannot accurately control the hot water temperature leaving a water heater with the thermostat dial.

If you adjust the water heater thermostat for the burner or heating element on a water heater down to 120 degrees, it will not prevent scalding. Water heater thermostats cannot be relied upon to control the hot water temperature leaving a water heater. Water heater manufacturers recommend that installers set thermostats at 120 - 125 F, and most of them ship the water heaters at an even lower temperature setting. It is not possible to set a water heater thermostat at a given temperature and get a relatively constant temperature of hot water from a water heater. The thermostat can not accurately control the water heater outlet temperature with a water heater thermostat.

My experience has been that not many people know that water heater thermostats cannot control the outlet temperature of a water heater. This warrants an explanation of how a water heater thermostat works so everyone understands the dial on the water heater does not have the accuracy to control the outlet temperature of storage type heater.

Water heater thermostats do not provide precise temperature controls for hot water systems. For example: the thermostat dial calibration test of ANSI Z21.10.1-1998, which is the applicable standard for gas-fired water heaters, allows the temperature to vary 10 degrees above or below the thermostat setting. I have talked to water heater manufacturers that have indicated that the controls can vary as much as 15 to 18 degrees Fahrenheit above or below the set point of the thermostat. From my experience, I have recorded the temperature leaving the top portion of a water heater over a long period of time during intermittent uses and saw temperature swings over 40 degrees Fahrenheit leaving the water heater. The shower valve standards do not have this kind of temperature fluctuation included their testing for all types of shower valves. The significant temperature swings are because the thermostat is inserted into the lower portion of a water heater tank and turns the fuel supply to the heater on and off. Most new water heater thermostat dials have no way to know what the temperature in the tank is. There is rarely a fixed temperature indicated on the dial, however some manufacturers publish temperatures associated with various marks on the thermostat dial or in their literature even though the dial cannot not control the outlet temperature of the water heater, it only controls when the energy to the heater is turned “on” and “off” by sensing the cold water coming into the bottom of the heater.

Generally, if the water heater thermostat dial is set at 120 degrees Fahrenheit, the burner would come on when the temperature at the thermostat reaches about 105 degrees Fahrenheit. The burner stays on until the water around the thermostat which is near the bottom of the heater reaches about 135 degrees Fahrenheit. (The “burner off” temperature is about 30 degrees higher than when the burner came “on” and generally about 15 degrees above the theoretical set point of the thermostat).

Most people don"t realize that the maximum temperature limit test of the ANSI Z21.10.1 Gas Water Heater Standard allows the outlet water temperature of the water heater to rise significantly above the thermostat setting. This provision in the standard accounts for the phenomenon known as "stacking" or "thermal layering". The hot water is less dense and rises to the top of the hot water tank. Just like hot air rises and lifts a hot air balloon, hot water rises to the top of the tank and the cooler water drops to the bottom of the tank. Stacking or thermal layering occurs when the hot water rises to the top of the heater due to recurring short duration heating cycles caused by a frequent number of small quantity hot water uses. Frequent short draws cause cold water to enter the bottom of the water heater where the thermostatic element senses the cold water from the turbulent flow stirring in the bottom of the heater. The cold water causes the water heater to cycle on. This phenomenon can occur in any type of storage water heater and generally is more significant in vertical heaters.

I have recorded temperatures as high as 150 to 166 degrees Fahrenheit at the top of water heaters that had the thermostats set between 120 to 125 degrees Fahrenheit. Temperatures over 151 degrees Fahrenheit are extremely high temperatures and can cause serious scald burns in only a two seconds of contact with the skin. (See Table 1 - Water Temperature Effects on Adult Skin) It should be noted that the time temperature relationships in Table 1 are based upon the thickness of the skin for adult males. Children and the elderly typically have a thinner layer of the skin or epidermis and the exposure times can be shorter or the same burns can occurs in a given time at slightly lower temperatures.

Kitchen sinks and lavatories have been the source of many scalding injuries because the codes do not have specific temperature limits listed for those fixtures. However it has been recognized by the industry that 120 degrees Fahrenheit is the maximum safe hot water temperature for showers and bathtub showers.

This is why I always recommend installing the proper type of an ASSE 1017 thermostatic mixing valve on the outlet piping of a water heater to limit the hot water distribution temperatures to a maximum safe delivery temperature of 120 F. If high temperature hot water is required for a specific use in a building, I recommend utilizing a piping branch with the 140 degree or higher temperature hot water for the specific uses and I use a master mixing valve conforming to ASSE 1017 or ASSE 1070 in-line which lowers the temperature for all of the hand washing and other sinks to a safe temperature and I use an ASSE 1016 or CSA B125.1 device for the individual showers or tub/shower combination fixtures in the building. You could use local mixing valve conforming to ASSE 1070 on the local branch piping serving a fixture or group of fixtures utilized for bathing or washing. Mixing valves can then reduce the hot water temperature to a safe temperature.

I always recommend setting the thermostat dial on the water heater at 140 degrees Fahrenheit and mixing the hot water down to a safe temperature with a master temperature actuated thermostatic mixing valve located near the water heater. The master mixing valve should conform to ASSE 1017 or CSA B-125.3. The mixing valve blends the hot water from the water heater storage tank with cold water and delivers a relatively constant temperature of tempered water to the plumbing system. The mixing valve can be set to deliver hot water to the system at or below 120 degrees Fahrenheit. This design reduces the threat of Legionella bacteria or any other organic pathogen growth in the water heater storage tank, and also storing hot water at 140 degrees Fahrenheit allows a smaller water heater than one with a lower stored temperature.

Hot water systems are generally designed and water heaters are generally sized to store hot water at 140 F. When the thermostat is set at a lower temperature, the water heater has a reduced capacity to deliver hot water and therefore should be larger.

Often when the water heater thermostat is adjusted down users run out of hot water, and the water heater thermostat is generally re-adjusted to a temperature above 120 F to adjust for the shortage of hot water during peak periods. When adjustments to the thermostat setting are made, most maintenance personnel and most users do not know they must also readjust the maximum temperature limit stop on all anti-scald type shower valves. Adjusting the thermostat increases the temperature to a scalding temperature at the shower or at other fixtures. In some cases, the thermostat is adjusted even higher than the original setting which creates an ever greater scalding risk. Even with the thermostat turned lower, the water heater will continue to be capable of storing and delivering hot water at temperatures well above 120 degrees Fahrenheit.

In my opinion, the answer to the equestion “What are safe hot water temperatures?” is always: “The maximum safe hot water temperature to prevent scalding is 120 degrees Fahrenheit.” The solution is using a master thermostatic mixing valve to control the hot water temperature to the domestic hot water system and you should use anti-scald shower valves at showers and tub/showers. You should never use the water heater burner control thermostat to try and prevent scalding injuries.

Every year, thousands of people suffer serious thermal shock or scalding injuries in their bathtubs, sinks, and showers. Additional untold numbers become ill due to water-borne bacteria, such as Legionella.

These are very common problems when your bathtub or shower has the old two-handle (hot and cold) shower valve. The simplest solution to this problem is to install a single-handle shower mixing valve with a pressure-balancing feature. The valve is designed such that if the cold or hot water pressure drops, the mixture still stays relatively balanced.

Did you know that if you have an old two-handle shower valve, you are not keeping current code requirements? As of January 1, 2011, Houston plumbing codes P. 2802.2 for Scaling Protection and 420.0 for Shower and Tub-Shower Combination Control Valves require Thermostatic mixing valves that control water temperature in new Houston homes, many of which have old shower systems and need to be replaced. Getting a Thermostatic mixing valve installed in your home not only will help you meet these requirements, but also ensure that you have the utmost safety and comfort when using your water.

The valve uses a thermostatic engine that is paraffin-based to keep a fairly steady exit temperature. If the water in the valve gets hotter than the set point, the paraffin expands rapidly, moving the valve hold to let more cold water in. If the water temperature drops below the set point, it then contracts, causing the valve to let more hot water into the mixture. If there is an interruption in the hot or cold water supply due to a failure of the cold or hot water supply, the valve will shut off completely. Because of the way it works, you get safety and comfort automatically.

Having a Thermostatic Mixing Valve installed in your home isn’t the easiest thing on the planet, but it definitely isn’t the most painful experience either. However, when dealing with these types of installations that require cutting drywall and soldering pipe, we recommend using the experienced, trusted hands, and of a John Moore technician. Plumbers will need to solder copper pipe to install the valve. We like Moen’s mixing valves, such as their M-Pact Thermostatic Mixing Valve 4796 ($119.10 MSRP), or their Moen 104465, which is a high flow mixing valve ($136.55 MSRP). Delta makes great and affordable mixing valves as well, like their R10000-UNWS MultiChoice Universal Tub and Shower Valve, which is only about $40 MSRP. According to Joe Bany, John Moore’s Plumbing Manager, and technician, the process is not hard but does require experienced hands to do it right.

Scalding incidents happen mostly in people’s homes- a danger while showering for anyone, especially the elderly and young children. Children, the disabled, and the elderly don’t react as quickly as others can to really hot water, making them more susceptible to burns. Injuries due to scalding are extremely painful, and can affect the victim for many years. Joe Bany said that getting up to code and installing a thermostatic mixing valve will prevent this from happening and keep you and your family safe.

In some cases, the water heater thermostat is damaged, or sometimes can simply be set too high. Also, temperature regulating valves at the household hot water source can be either faulty or not there altogether. Because Water heaters are normally set to temperatures over 140°F to prevent the development of harmful bacteria, there is a huge risk of scalding if there is no automatic temperature control, as there is with a thermostatic mixing valve for your shower. Water at temperatures above 106°F is painful for us, so at a temperature of 140°F and above, a small child can be burnt in a matter of seconds.

Have you ever had a close, dangerous call when reacting quickly to a sudden change in your water’s temperature while enjoying a shower? Have you ever slipped and fallen, even hurt yourself? This is what is known as thermal shock, and it happens more often that you may think- especially with old, two-handle valves that many Houstonians have in their homes that tend to change the temperature at a simple flush of a toilet. Thermostatic mixing valves will maintain and limit mixed hot water to a comfortable and safe temperature, helping to minimize thermal shock.

Ideally, if the supply of cold or hot water is lost, the water flow should be shut down immediately. That’s where the new and improved thermostatic mixing valve comes in. Termination of flow of the cold or hot water will eliminate the instinctive but super-dangerous reaction to move away quickly from a too hot or too cold water stream.

Legionella is a somewhat common water bacterium that exists in many surface water sources such as lakes, rivers, streams, and ponds. It can also be found in ground water sources and some soils, which don’t usually threaten public health. However, when the bacteria enters a household water system, it can find the perfect host environment of warm water temperatures, inactive water areas (think storage tanks and dead-end piping legs) and plenty of food sources (things like sediment, scale, and biofilm) for them to keep growing and reproducing. Under these conditions, Legionella is able to quickly colonize and form higher concentrations that can threaten the health of you, your family, and others in the community.

A widely accepted and preferred method of controlling this bacterium is to keep the hot water system storage temperature constantly at or above 140°F. Unfortunately, the elevated temperature necessary to minimize the growth of and kill Legionella bacteria has the potential to cause serious thermal shock and scalding injuries. A Thermostatic Mixing Valve will maintain and limit the mixed hot water to a desirable, selectable temperature while still allowing for the storage of domestic hot water at the higher temperatures necessary to reduce the risk of Legionella growth in your system.

You may think that you have the hang of your old, two-handle shower system and know all of its nicks and knacks, but it only takes one unguarded moment to hurt you or someone you love. Basically, you aren’t Superman (or woman!) and unexpected things do happen all the time that we didn’t really think would or could. All the things we mentioned are serious threats that can go undetected or just ignored for quite some time, so we urge you to look into how your system is functioning and whether it’s time to consult a trusted John Moore technician. Call John Moore today to learn more about what you can do to be on the way to showering comfortably and with peace of mind that you are clean and safe!

All Delta tub and shower faucets are engineered to keep the water temperature within a safe ±3.6° F (±1.7° C)*. This technology makes sure your family doesn’t experience a sudden and possibly unsafe change in water temperature as a result of running water elsewhere, such as using a dishwasher, flushing a toilet or running a washing machine.

Delta thermostatic tub and shower faucets are built with TempAssure valves, while pressure balance tub and shower faucets are built with Delta Monitor valves. Both feature an adjustable handle limit stop that, when properly set, helps ensure the handle cannot be turned to a position that is too hot for comfort.