What is the hot water regulation valve?

The hot water regulation valve, also known as a tempering valve or mixing valve, is an important component in domestic and commercial hot water delivery systems. It blends hot water from the water heater with cold water to deliver tempered water at a safe and usable temperature to fixtures. The valve prevents scalding by limiting the hot water temperature.

What does a hot water regulation valve do?

A hot water regulation valve has several key functions:

• Mixes hot and cold water to reduce hot water temperature to a preset safe level
• Prevents scalding by limiting maximum hot water temperature
• Compensates for fluctuations in hot water supply temperature
• Maintains relatively constant outlet temperature even as incoming hot or cold water pressures vary

The valve mixes a portion of hot water from the water heater with colder water from the main cold water line to achieve a target tempered water delivery temperature. This temperature is usually set to 120°F or lower for residential applications and 140°F or lower for commercial settings to prevent scalding. The mixing ratio is controlled by the valve so that even as the hot water heater cycles on and off and temperatures fluctuate, the outlet remains steady.

How does a hot water regulation valve work?

A hot water regulation valve works by using the feedback from a temperature sensitive element to modulate the flow of hot and cold water. The key components are:

• Temperature control element – This is the thermostat that measures mixed water temperature. It may be a bi-metallic coil, wax element or electronic sensor.
• Balancing valve mechanism – This proportionally mixes hot and cold water to maintain the set temperature. It may use a piston, diaphragm, or rotary disc.
• Spring or pressure differential – This acts against the force of the temperature control element to regulate the water mix.
• Shut-off valves – Allow isolation of hot and cold supply lines for maintenance.
• Check valves – Prevent crossflow between hot and cold supply lines.
• Strainers – Filter debris that could clog internal components.

As the mixed water temperature rises, the temperature control element expands which pushes against the spring or pressure differential. This actuates the balancing valve to modulate the flow, increasing cold water volume and decreasing hot water until the set temperature is reached again. The reverse happens if the mixed water gets too cool. This dynamic self-regulation keeps outlet water temperature steady.

What are the different types of hot water regulation valves?

There are several different designs and types of thermostatic mixing valves:

Standard thermostatic mixing valves

• Bi-metallic coil thermostatic valve – Uses a coiled bimetal spring as the temperature control element.
• Liquid-filled thermostatic valve – Liquid-filled bulb acts as the thermostat.
• Wax element thermostatic valve – Wax-filled cartridge acts as the thermostat.

Electronic thermostatic mixing valves

Instead of a mechanical thermostat, these use an electronic temperature sensor and electric actuator to control water flow. They allow more precision temperature setting and control.

Pressure balance valves

These mix hot and cold water based on the pressure differential instead of temperature. They respond more quickly to pressure or temperature changes but do not regulate temperature as accurately.

Thermostatic blender valves

These are designed for commercial or large domestic water heaters to blend water across the entire temperature output range rather than at a preset point.

Point-of-use thermostatic valves

Small under-sink or countertop valves deliver tempered water at a specific tap or fixture instead of the whole plumbing system.

What are the main components and parts?

The main components of a standard thermostatic mixing valve are:

• Temperature control element (thermostat) – Responds to mixed water temperature
• Spring or pressure differential – Opposes temperature element force
• Balancing valve – Proportionally mixes flows
• Check valves – Prevent crossflow between hot and cold lines
• Isolation valves – Allow maintenance without shutting water off
• Strainers – Filter out debris
• Adjustable temperature limit stop – Limits maximum temperature setting
• Temperature adjustment knob – Sets desired mixed temperature

The thermostat and balancing valve are the key components that regulate and blend the water. Other parts like checks valves, strainers, and isolation valves support operation and protect the inner workings. The temperature limit stop and adjustment knob are external controls. More advanced digital mixing valves replace the knob with electronic control.

Where are hot water regulation valves used?

Hot water regulation valves have several residential, commercial, and industrial applications:

Residential uses

• Under sinks – For lavatories and kitchen sinks
• Showers and tubs – To prevent scalding
• Dishwashers and washing machines – For hot water supply
• Whole house mixing – Central valve for hot water distribution

Commercial uses

• Public restrooms and locker rooms
• Hotels and apartment buildings
• Hospitals and nursing homes
• Commercial kitchens and laundries
• Schools, daycares, churches

Industrial uses

• Factory washrooms and showers
• Laboratory water supply
• Process water heating and cooling
• Washdown stations

Any application that uses hot water for handwashing, bathing, cooking, cleaning, or processing may require temperature regulation for safety and proper function.

What are the benefits of thermostatic mixing valves?

Key benefits of installing thermostatic mixing valves include:

• Prevents scalding injuries – Limits hot water temperature to prevent accidental scalding.
• Temperature stability – Maintains consistent outlet temperature during water heater cycles.
• Faster hot water delivery – Allows higher water heater temperature then mixes down for energy savings.
• Improved comfort – Provides satisfactory bathing and washing temperature.
• Protects fixtures – Avoids damage from extreme high or low temperatures.
• Reduces risk – Complies with plumbing codes and health regulations for hot water safety.

Thermostatic valves are an affordable way to regulate hot water systems for optimal performance, safety and energy efficiency. Their regulating ability provides scalding protection across the whole plumbing system.

What are thermostatic mixing valve safety standards?

In the United States, thermostatic mixing valves must comply with:

• ASSE 1017 – Performance Requirements for Temperature Actuated Mixing Valves for Hot Water Distribution Systems
• ASSE 1069 – Performance Requirements for Automatic Temperature Control Mixing Valves
• ASSE 1070 – Performance Requirements for Water Temperature Limiting Devices
• ADA – Americans with Disabilities Act standards for accessible design
• ASME A112.18.1 – Plumbing supply fittings

These standards regulate maximum hot water temperatures, minimum flows, pressure loss limits, crossflow protection, and reliable shut-off. Commercial mixing valves also adhere to hygienic design principles. Compliant valves are certified and display markings such as ASSE 1017. Learning the standards helps ensure the valve specified suits the application.

What are the maximum hot water temperatures?

Hot water regulation valves are typically set to deliver water at these maximum temperatures:

Residential

• Kitchen sinks – 120°F
• Showers and tubs – 120°F
• Lavatories – 120°F

Commercial

• Public and shared restrooms – 110°F
• Childcare facilities – 110°F
• Hospitals – 110°F
• Nursing and care homes – 120°F
• Offices and workplaces – 120°F

These limits are set by plumbing codes like UPC and IPC as well as ADA standards. Lower temperatures reduce scalding risks for children, elderly, and people with disabilities. Meeting the limits is required for new constructions and renovations.

How are hot water regulation valves installed?

Installation of thermostatic mixing valves involves:

1. Turn off hot and cold water supply lines
2. Mount the mixing valve on the wall or under sink
3. Connect hot and cold supply lines to correct valve ports
4. Connect outlet line from valve to plumbing fixtures
5. Install check valves on supply lines if not integral to mixing valve
6. Open isolation valves and flush debris from housing
7. Turn on water supply and check for leaks
8. Power on and program electronic mixing valves
9. Set desired tempered water temperature at outlet

Proper mounting height, clearance, pipe sizing, and outlet orientations are also important. Installers should follow manufacturer instructions. Faulty installation affects performance and safety.

How are thermostatic mixing valves set and adjusted?

1. Turn temperature adjustment knob counterclockwise to the lowest setting
2. Turn on outlet fixture and allow water to flow
3. Slowly rotate knob clockwise until desired maximum temperature is reached
4. Check temperature with a thermometer if possible
5. Install handle limit stop against knob to prevent readjusting to higher temperatures

For electronic mixing valves, the temperature is set digitally usually with buttons or a display screen. The valve should always be adjusted to the lowest required temperature for the application to prevent scalding.

How are thermostatic mixing valves maintained?

Routine maintenance is needed to keep thermostatic mixing valves working properly:

• Check outlet water temperature 6-12 months
• Inspect for leaks annually
• Remove and clean strainers and check valves
• Flush valve housing to purge sediment
• Clean thermostat and balancing valve internals
• Replace worn o-rings and seals
• Test response to hot and cold pressure changes
• Confirm fail-safe operates properly

Electronic valves may also require battery changes and firmware updates. Failing to maintain valves can lead to unreliable operation and temperature fluctuations.

How much do hot water regulation valves cost?

Hot water regulation valve costs depend on:

• Type – Standard, pressure balance, electronic, point-of-use etc.
• Size – Valve capacity in gpm or pipe diameter
• Features – Check valves, isolation valves, warranty
• Brand – Budget or premium manufacturer

Typical valve costs for single residential installations:

• Basic mechanical under sink valve – $20 – $60
• Advanced electronic central valve – $200 – $500
• Whole house mechanical valve – $80 – $150

Commercial and industrial valves run $300 to well over $1000 depending on capacity and engineering. Smart WiFi-enabled electronic valves cost even more. Installation labor also adds to the total project cost.

Conclusion

A hot water regulation valve is an indispensable component of modern water heating systems. By intelligently blending hot and cold water, it delivers tempered water at a consistent, safe temperature to prevent scalding. Selecting the right mixing valve and proper installation ensures optimal performance. Maintaining valves extends service life. For residential comfort and commercial safety, thermostatic regulation of hot water systems is critical.