How important the PT valve in the Pressure Solar Water System

Everything needs control and balanced working. Like the PT valves, it is a safety valve to control the pressure and temperature of the hot water system.

What Does PT Valve Mean?

PT stands for ( Pressure And Temperature) it’s also known as PTR, which means ( pressure and temperature relief valve). It’s used to provide safety and protect your system from overheating damages. It is a safety protection device for solar water heaters.

This PT valve connects to the storage water tank of the solar heating system. When the temperature rises, the quantity of the water expands, and the pressure inside increases at the same time.

PT valve works in two modes: Temperature and second is Pressure.

How Does the Pressure System Work?

This feature is used to control pressure value When the tank pressure increases to the set value. The PT valve helps to protect your solar hot water system by draining the pressure.

The primary purpose of a pressure Relief Valve is to save water from overheating and protect life and property by venting fluid from an overpressurized vessel. Moreover, a pressure system is also capable of operating at all times, especially during failure when system controls are nonfunctional.

Things to be noted

  • In normal operation, no water is discharged from the valve.     
  • Must use the same size discharge line as the valve outlet.
  • Discharge from a T&P valve may indicate an unsafe temperature or pressure condition and require immediate attention.

How Does a Temperature Work?

It controls the temperature and maintains the desired level. A solar heating system must require this equipment to secure the entire solar system from any overheating issue. So, when the temperature increases to the desired value PT valve opens, and the water drains out. Meanwhile, cold water ( groundwater) enters the tank and maintains the temperature level of the solar heating system. It’s beneficial to protect the system by reducing the temperature and pressure inside.

The PT valve opens when either temperature or pressure meets the set value.

How Does T&P Relief Valve Work?

It’s very essential to prevent any dangerous situation with an electric heater, thermal or solar heating system. Plumbing needs expertise and is well addressed. If it’s not installed correctly or has an issue with capped or clogged water heaters, the TP valve is one of the worst “band-aid” fixes you could ever do in your house. Like fire as a potential bomb or missile in your basement or ground floor. Although rare, the threat of a water heater explosion is very real. It is important to contact a licensed and highly experienced plumber to fix your water heater instead of using DIY “band-aid” fixes.

Moreover, the working of the TP valve, which is also known as TPR, means Temperature and pressure relief valve work as a safety device for your heating system. When you set the temperature to the desired point, if it’s increased above 210 degrees which is Considered extremely hot, and the pressure rises 150 psi, the pt valve protects your system to control the exceeding temperature. Pressure and the valve automatically open and relieve the pressure inside the tank.

In doing so, some water is also b drained to the floor to set the temperature in this situation. Unfortunately, many people mistake this for leakage or a heating system failure. It’s actually protecting your system from any blander, and it is doing what it is designed to do. So if anyone who has a solar water heating system or other systems ever sees the water on the ground, you should call a plumber right away.

In that case, the pressure is excess mainly to control your tank’s temperature, and maybe the valve is failing, which should be replaced or tested.

If a pressure-reducing valve is installed in the hot water system of the main water line, you have to be conscious of this because it creates a closed system in your home and should have a thermal expansion tank installed.

Now it’s time to check out the system and ensure it’s plugged or not? If it’s not called, it means it’s working correctly; otherwise, you can also check by moving the handle that you know what it looks like and how it’s working. Lift the little screw and let the handle snap back to reseat it properly. If leakage happens, it either spring fails or has some debris in it l. Try again and open it a few times to remove any debris.

If it’s not set, you just call the experienced plumber, and it must have to be replaced.

Sometimes, there is a relief tube installed to extend to the floor. That’s why the heater discharges. Sometimes, there are threads on the bottom of the relief tube. This will ensure that a cap cannot be screwed onto the bottom.

T&P Relief Valves on Residential Water Heaters are designed to maintain the pressure at 150 psi for residential water and a temperature range of 210 degrees Fahrenheit. These types of systems are Tested, and safety proof such as ASME, ANSI and CSA (AGA) approved, which helps to maintain the temperature and pressure and prevent excess pressures and temperatures by discharging water.

In general, working the water heater does not discharge from the valve. The valve discharge is rare and only occurs when abnormal conditions are in the system. The T & P valve is specially designed to secure the system. If there is any discharge causing excess temperatures in the heater, such as too low water pressure, too high temperature, water flows slow, discharging, etc.

Temperature and Pressure relief valves Features

There are many varieties of relief valves you can see in the market today with enormous versatility in features designed and function.

  • Hygiene manufactured
  • Take minimal time to test and operate
  • Required Low maintenance
  • Helps to eliminate surges and prolongs pipe life
  • Control higher Pressure application quickly and efficiently
  • Closes drip-tight
  • Affordable
  • Adjustable closing speed

What is a pressure and temperature release PT relief valve?

All hot water systems must-have safety features that control temperature and pressure perfectly. It’s designed to temporarily open and discharge short spurts of water when the temperature exceeds 210 degrees Fahrenheit, and it releases pressure if the tank is above 150 psi.

For instance, if the temperature is too high and there is a malfunction with the thermostat, the valve will open to allow steam to escape safely. Water heaters can explode if the pressure system does not work correctly and gets too high.

So, it would be best if you considered some tips about your TPR valves. Things to look for:

  • You see water leaking from the TP valve, so don’t worry. It’s normal. It’s occurred during water heating to maintain temperature by running excessive amounts of water flow from the pressure system.
  • Water running down the roof into your gutters.
  • Water may flow down through the drain line situated outside the wall.
  • Steaming hot water pouring out of the PTR valve.

How to test T and P valves on Solar Hot water Systems?

Before moving to the simple test point of the T and P valve, we should know about What is Dripping T&P Valve? 

Every hot water system needs a T and P Relief valve to control the entire system performance without one the system failure and doesn’t work properly, and even it could cause water leakage or high explode. The temperature and pressure relief valve is located on the top middle of the tank, which has the open and close screw used to open and realise the water when the temperature or pressure exceeds preset limits.

So, if your valve drips and exceeds the preset point, it may cause it to work perfectly, but some checking will help determine if it’s doing its job perfectly or not.

Testing 1:

You can test if the solar system function does the T and P valve working well or not by checking the hot water temperature. Simply run the hot water from the hot water faucet, which is near to the heating system, for one minute and check the water’s maximum temperature point. You can fill the tub with a hot water faucet, take some boiling water in cups, and check the temperature with a thermometer. If the temperature is under 200 degrees Fahrenheit, it would be ideal. Otherwise, If the temperature is above 220 degrees Fahrenheit, the valve may be about to open because most are set to open at 210 degrees Fahrenheit.

Testing 2:

The second cause of poor valve performance may be a pressure system failure. Check the pressure of your hot water system with a water pressure meter. Turn on all the way and put the screw onto a basement hot water faucet note the accurate reading. If it’s reading between 60 and 80 pounds per square inch, then it works good and does not doubt the pressure system, but If the value is close to 150 psi, which is the pre-set threshold for most valves, the T-and-P valve is dripping because it’s about to open.

Testing 3:

The next thing to determine the problem by checking the Keeping the valve on the faucet and empty the storage tank halfway. Don’t waste the water. You can remove water by running a bath or taking a shower. After having half the tank, now check the valve as the water in the tank reheats. It could be higher than 80 psi with pressure less than that because of thermal expansion. If it happens, that’s one of the causes of dripping T-and-P valves.

Testing 4:

The last is that you ensure your whole system performs well and there is no issue created by the valve. But one thing may be because the opening of the valve is not perfectly connected to the overflow tube.

If so, water starts running when you Lift the rocker arm on top of the valve. When you release the arm, it should snap back down, and the water should stop flowing. In that process, if it doesn’t snap down, then the problem with the valve you should replace immediately.


  • It’s crucial all the parts should be appropriately installed and tested by an expert plumber.
  • The discharge from the temperature and pressure valve may be very hot to keep pets and other animals from the hot water heating system.
  • We suggest that Automatic Shut-Off Devices combine temperature and pressure relief valves with extension thermostats that control heating and pressure systems by sensing whether installed within the hot outlet service line or directly in a tank tapping.
  • It’s better to avoid scalding due to valve operation and the discharge line connected to the valve outlet.
  • Avoid using a shut-off valve between the relief valve and tank or in the discharge line.
  • The valve level may drop after one year. It needs annual maintenance and repair.
  • A qualified service technician or licensed plumbing contractor must install the entire system.
  • A licensed plumber should check the T and P valve for at least 2 to 3 years and replace the damaged parts.
  • Make sure to use only those parts of the system that are not affected by corrosive water conditions.
  • Also, ensure that the valve and discharge line have not been altered or tampered with illegally.
  • Don’t attempt any inspection of the heating system; it may cause a vast blast. Avoid inspection on your own. In any case, only Contact your plumbing contractor for a re-inspection.
  • Temperature and pressure relief valves with missing data plates should be adequately replaced.
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