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T&Pvalvevs pressure reliefvalve

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T&Pvalvepipe

When a check valve (backflow preventer) or pressure reducing valve is installed without a built-in bypass water is not allowed to push back into the supply line. Pressure instead builds within the water heater. At 150 psi the T&P will begin releasing water to reduce the pressure within the water heater for your protection.  Should this occur we recommend that you install a properly sized expansion tank. An expansion tank helps by absorbing the excess water pressure in a diaphragm tank. The diaphragm allows for water to flow into the expansion tank as it is being heated and expanding and flow back into the water heater at other times. An expansion tank will prevent wasting water released from the T and P during expansion, as well.

The temperature and pressure relief valve is a safety device that is installed at the factory.  It is designed to open on a residential water heater, for your protection, when there is excessive water temperature or excessive water pressure. There are many things that result in conditions causing a T&P to release water. Thermal Expansion in a closed system is a common cause that is often the last to be considered.

A TMV mixes both hot and cold water together so it is a particular temperature (within 1℃ +/-) so it can be sent to different water outlets. The temperature is generally prearranged by a tradesperson or a qualified plumber, and the TMV element that responds to thermal activity alters the levels of hot and/or cold water to ensure the correct temperature.

T&PvalveHome Depot

T&Pvalvedripping

When you turn your hot water tap on, you expect hot water to flow out. Whether it is a shower, bath, kitchen sink or laundry basin, water at a particular temperature will always run from the faucets in your home or workplaces. But how does that occur?

Tempering valves and TMVs are the devices responsible for ensuring that the water that comes out of your tap is safe and at the right temperature. But, what is the difference?

https://www.health.qld.gov.au/public-health/industry-environment/environment-land-water/water/risk-management/plan/implement/monitoring-temperature

T&Pvalvemeaning

The mixing valve is a sliding component that is found in the tempering valve, ensuring the correct ratio of hot to cold water is being allowed to flow through. A tempering valve usually controls the temperature within ±3%.

T&Pvalvediagram

A thermostatic mixing valve, which is also known as a TMV, is a tool that combines hot and cold water together to maintain a specific water temperature when sending water through a faucet.

T&Pvalvewater heater

When water heats it expands, just as mercury in a thermometer expands rising up the scale to show you a person’s body temperature. If the expansion of the mercury were to exceed the capacity of the thermometer the thermometer would explode. When water heats in a water heater it also expands. The expanding water will typically push back into the supply line preventing excessive pressure from building inside the water heater.

A tempering valve has a temperature sensitive element which focuses on adjusting the mix of hot/cold water depending on two factors:

When water heats in a water heater it expands. The expanding water will typically push back into the supply line preventing excessive pressure from building inside the water heater and often causing a drip or leak from the T&P valve

Why would a backflow preventer/check valve be installed in the first place? To prevent your home’s water from backing up into the main supply. Removal of the backflow preventer/check valve may not be an option, as it is likely required by codes in your area. Removal of a pressure reducing valve is also not a likely option, as controlling the water pressure into the home may be necessary.

According to Queensland legislation, hot water is to be heated to a minimum of 60°C to prevent the growth of bacteria such as Legionella. A tempering valve ensures that hot water flows from taps at a maximum temperature of 50°C.

A tempering valve, which is also known as a hot water mixing valve or a hot water tempering valve, is either a 2-inlet or 3-inlet mixing valve which is adjustable and activated by temperature. It mixes both hot and cold water together to achieve a desired temperature, in order to regulate the temperature of hot water that flows from outlets in your home.

T&Pvalvereplacement

https://www.business.qld.gov.au/industries/building-property-development/building-construction/laws-codes-standards/sustainable-housing

According to National Plumbing and Drainage Standard AS/NZS 3500.4: 2003, some water installations are not permitted to deliver water at a temperature higher than 50℃/45℃, which is why a TMV is installed – to assist with temperature regulation.

Although TMVs and tempering valves get regularly mixed up, they are actually two separate devices. They both mix hot and cold water together to achieve a specific water temperature, but there are a few notable differences:

Thermostatic mixing valves are required by law in the following locations, due to the possibility of high risk people being present (such as the elderly, sick or children):

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