Wy a thermostatic mixing valve ?

WHY A THERMOSTATIC MIXING VALVE ?

The principle of automatic control of hot and cold fluids ensures you of efficient management of hot water :
no water and energy are wasted through trial and error when adjusting the temperature ; reduction of in-line heat losses ; temporary interruption of the controlled temperature water flow as often as required.

The thermostatic mixing valve assists in ensuring that the system components such as tap heads, seats and
solenoid valves are less encrusted with scale, thus ensuring a longer service life of all the equipment and piping.

It significantly increases the output capacity of the accumulator.

The WATTS Industries interchangeable mixing valve mechanism also contributes to savings by enabling a mixing valve to be renewed for a lower cost.

It is commonly accepted that a thermostatic mixing valve provides energy savings of 30% compared to a simple mixing valve.
For private individuals, the equipment is soon amortized.

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PREVENT THERMAL SHOCK AND SCALDING INJURIES

Hot water burns like fire. The tender skin of very young children and the slow reaction time of the elderly and the handicapped make them most vulnerable to serious hot water burns.

Scalding injuries are tremendously painful, and the effects can last for years.

Scalding occurs for a variety of reasons. In some cases, water heater thermostats are faulty, or set too high.
In others, temperature regulating valves at the domestic hot water source are either malfunctioning or missing altogether.

Water heaters are normally set to temperatures above 55°C to prevent development of harmful bacteria, such as Legionella, in the water supply. Water at temperatures above 43°C are painful.
At a temperature of 55°C, a child can be scalded in less than 4 seconds.
80 per cent of thermal injuries to children happened at home.

According to the new European standard EN1717 (protection against pollution of potable water in water installations and general requirements of devices to prevent pollution by backflow), thermostatic mixing valves must be equipped with approved check valves.

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FUNCTION

A thermostatic mixing valve mixes cold and hot water, generally with a temperatures differential of at least 7°C, in order to obtain mixed water at a stabilized temperature.
Therefore, it must compensate for pressure variations (frequent or abrupt), and temperature variations (slower).
A real thermostatic mixing valve regulates both on the hot and cold water inlet, and compensates for the pressure variations.
It operates through automatic management of the admission of the hot and cold water, depending on a set point displayed on the handle.
This automatic control is carried out entirely by the internal thermostat.
The original, superior feature of the thermostatic valve over all the other principles is the mixing chamber, with automatic reaction and automatic preservation of temperature.
If the pressure varies, the temperature in the mixing chamber varies, and correction is carried out in less than 2 seconds (this is equally true if the flowrate or temperature varies).

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2 TYPES OF TECHNOLOGY : WAX ELEMENT AND BIMETALLIC STRIP

Products with Wax element : MMV, TL117, T9107, T9715, MINIMIXING + inset mixing valves T8175, T8147

The technique of these models is that of automatic regulation via a cylindrical "slide valve", activated by a wax capsule up to flowrates of approximately 40 l/min.
It is quite standard and competitive, but quickly reaches its limits beyond 40 l/min.
The hot and cold water inlets are located on other side of this "slide valve”. When the water is too cold as regards the set point (upon opening), a spring pushes the "slide valve" and closes the cold side and thus opens the hot side completely.
As soon as the hot water comes in, the capsule expands and draws the "slide valve” of the other side, closing the hot side and compressing the spring. As the cold water then flows in again, the spring will bring the "slide valve" to the hot side and reach the proper mixing temperature.
All these operations are carried out in less than 2 seconds. Should the pressure vary, the same operation will be repeated.

Products with Bimetallic strip : ULTRAMIX TX91, TX92, TX93, TX94, TX95, TX96, OMDA, FNC, Flanged Mixing valves (DN65, DN80 and DN100) + inset mixing valves TX8256, TX8280, TX83, TX84, TX85, TX86, TX824056, TX824080, TX824456, TX824480

Trubert is the inventor of the Bimetallic strip concept.
Trubert is one of the most well-known names in thermostatic control and is our original brand name for thermostatic items.
The TRUBERT Eurotherm technique uses the principle of double control through indirect action of a bimetallic strip.
This receives temperature information corresponding to the set point and will react instantaneously (+/- 1 sec.).
The double control will take place as follows : the bimetallic strip acts on a pre-mixing valve with a very small flowrate, also called the distributor, this will regulate the flow of water in two slave valves with membranes, causing an amplification of the signal, but ensuring the same mixture proportion and thus the same temperature.
The slightest variation in use conditions will be passed along to the same operating chain : first the distributor and then the large water passages.
This technology is the basis of the WATTS Eurotherm success, since it combines substantial regulation and scale-resistance qualities (a decisive element for safety).

Water mixing is obtained by two independent valves - one for hot water, one for cold water - which operate like two hydraulic relays.
These two valves are controlled by a bimetallic strip that records output water temperature.
Its position can also be adjusted by means of the mixing valve's control knob.
The water runs at exactly the desired temperature.
If it goes off by just one degree, the bimetallic strip instantly adjusts water mixing.

This operational principle provides many advantages :

No load from water pressure is exerted on the bimetallic strip.
Due to the bimetallic strip's high sensitivity and nearly non-existent inertia, it is not subject to any load and the mixing valve reacts instantly.

Nearly non-existent hysteresis and improved durability over time with the bimetallic strip.

No friction from moving metal parts means excellent resistance to scale and remarkable longevity.

Thanks to the relay operational principle, low and high flow rates receive the same adjustment quality (which is not true of all solutions available on the market).

Anti-scalding feature : The hot water shuts off automatically if there is not enough cold water.

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LEGIONELLA : FAQ (FREQUENTLY ASKED QUESTIONS)

What is legionnaires' disease ?
Legionnaires' disease is a bacterial disease which may cause pneumonia.
The majority of cases are reported as single (isolated) cases but outbreaks can occur.

Why is it called legionnaires' disease ?
An outbreak of this disease in Philadelphia in 1976, among people attending a state convention of the American Legion and led to naming the disease after this group. Subsequently, the bacterium causing the illness was identified and named Legionella pneumophila.

Is this a new disease ?
No. While the bacterium was only recently identified, cases have been confirmed as far back as 1947 and some probably occurred before then.

How widespread is the disease ?
Cases have been reported from all industrialised countries. Around 200 cases are reported each year in England.

Where are legionella organisms found ?
Legionellas are widely distributed in the environment. They have been found in ponds, hot and cold water systems, and water in air conditioning cooling systems.

How is legionnaires' disease spread ?
The disease is spread through the air from a water source. Person to person transmission does not occur. Breathing in aerosols from a contaminated water system is the most likely route of transmission.

Who gets legionnaires' disease ?
All ages can be affected but it mainly affects people over 50 years of age, and generally men more than women.

What are the symptoms ?
The early symptoms of legionnaire’s disease include a 'flu-like' illness with muscle aches, tiredness, headaches, dry cough and fever. Sometimes diarrhoea occurs and confusion may develop.
These symptoms frequently lead on to pneumonia.
Deaths occur in 10-15% of otherwise healthy individuals and may be higher in some groups of patients.

How soon do symptoms occur ?
The incubation period ranges from 2 to 10 days but is usually 3 to 6 days.
In rare cases some people may develop symptoms as late as three weeks after exposure.

What is the treatment ?
Antibiotics are effective in treating the disease.

How is it diagnosed ?
A rapid diagnosis can be made by testing an urine sample from the patient, once the relevant symptoms have occurred.

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KEY POINTS TO PREVENT LEGIONELLA

All over Europe, the Legionella disease changes habits and National Regulations.
Main contamination by Legionella is due to evaporative condensers and air conditioning systems (cooling towers), spa pool and spray humidifiers or air washers.
Water systems may occasionally be contaminated by Legionella which enters cold water storage systems from the main supply.
Legionella will only grow in sanitary distribution network when there are increased temperature, appropriate nutrients and stagnation.

The sanitary network has to comply with the national regulations.
Analysis of water samples for Legionella should be carried out regularly.

The main keys points of the Regulation are* :
- 2 methods for fighting against these bacteria : thermal shock or chemical shock
- increased hot temperature from the heater (use water heaters with minimal or no storage)
- all storage water heaters should have a drain valve located in an accessible position at the lowest point
- of the vessel (accumulated sludge can be drained easily)
- permanent chemical treatment must be avoided
- use of recirculation systems : circulating loops
- ensure that the target temperature is achieved throughout all levels of the loop
- mixing valves must be as close as possible to the point-of-use
- mixing valves must have integrated check-valves
- equipment must allow easy cleaning and disinfection operation
- if a single mixing valve serves a multiple showerheads, these showers must be flushed frequently
- circulating loop should be designed to return the mixed water to the storage not less than 50°C*
- (55°C for Belgium and UK - 60°C for The Netherlands)
- hot and cold water distribution pipes must be insulated sufficiently (never together)
- dismantle and clean hoses, tap, showerheads and mixing valves minimum once a year
- * according to National Regulation

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