What’s a Radiator Valve?

In this blog post, you’ll read:A radiator valve is a self-regulative valve attached to the radiator to control the temperature of a room. To clarify, it's a valve fitted with the radiator and controls hot water flow for the radiator to change the temperature of the room.
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What is a Radiator Valve?

radiator valve is a self-regulative valve attached to the radiator to control the temperature of a room. To clarify, it’s a valve fitted with the radiator and controls hot water flow for the radiator to change the temperature of the room. It’s also known as the Thermostatic Radiator Valve (TRV).

Hand turns radiator thermostat to minimum, due to rising gas prices, energy crisis and economy
Hand turns radiator thermostat valve.


Generally, two types of radiator valves are availableManual and Thermostatic. However, some companies manufacture a different kind of it… that is, an intelligent radiator valve. 

Manual Radiator Valve

This is the most commonly used type of radiator valve. You can open, close, or partially open it to control your room’s temperature. Also, it is helpful for constant heating. For example, if you need idle heat for your room, this valve can help you. 

But the downside is that this type of valve is not automated. They will heat all your rooms all day and night, but it’s unnecessary. So, it would be best if you controlled it manually whenever you want to change the temperature.

manual radiator valve parts
Manual radiator valve parts

Thermostatic Radiator Valve

Thermostatic Radiator Valves (TRV) come to remove the drawbacks of the manual types. This is an automated valve, so you don’t have to control it. In addition, you can set the radiator to a certain level… and when it touches that point, this valve will shut off to stop further water flow into the radiator. However, TRVs are way more efficient than manual ones.

Pre-setting radiator valve?

A pre-setting radiator valve, often referred to as a thermostatic radiator valve (TRV) with pre-setting functionality, is a type of valve used in heating systems, particularly in radiators. Its primary purpose is to regulate the flow of water into a radiator based on the setting chosen, ensuring that each radiator receives the appropriate amount of hot water to maintain a desired room temperature. Here’s a more detailed explanation:

How Does a Pre-setting Radiator Valve Work?

  • Temperature Regulation: Traditional TRVs regulate the flow of hot water to the radiator based on the ambient room temperature. If the room temperature drops below the set point on the TRV, the valve opens to allow more hot water in. If the room’s temperature is above the set point, the valve reduces or shuts off the flow to the radiator.
  • Flow Limitation: The pre-setting function on these valves allows for an additional layer of control by limiting the maximum flow rate to the radiator regardless of the thermostatic setting. This is particularly useful in balancing systems, ensuring that each radiator in a building gets the right amount of flow to heat the space it serves without ‘hogging’ the flow and leaving other areas cold.

Benefits of Pre-setting Radiator Valves:

  • Energy Efficiency: By ensuring that each radiator only gets the amount of hot water it needs, you can reduce energy consumption and increase efficiency.
  • Comfort: Properly balanced systems provide a consistent temperature across all rooms, leading to enhanced comfort.
  • Cost Savings: An efficient heating system will use less energy, leading to reduced heating bills.
  • Reduced Noise: Balancing the system can eliminate common issues like water hammer or noisy circulation, creating a quieter heating system.
  • Flexibility: These valves allow for individual room temperature settings, giving occupants more control over their environment.
pre setting trv
pre setting trv

Installation and Use:

While the installation of a pre-setting radiator valve is best left to professionals to ensure it’s done correctly, using the valve is generally straightforward:

  • Pre-setting: This is typically done using a specific tool or a built-in knob on the valve. The installer will determine the appropriate setting based on the size of the radiator, the room’s heating requirements, and the overall system design.
  • Thermostatic Control: Once the pre-setting is done, the occupant can adjust the thermostatic control, usually by turning a knob to the desired room temperature.

Pre-setting radiator valves offer a combination of thermostatic control with flow limitation, effectively balancing heating systems and enhancing energy efficiency. If you’re considering an upgrade to your heating system or facing issues with uneven heating, these valves might be a suitable option to explore.

Made of

A radiator valve is a combination of two different parts. These are the plastic part’s upper side (thermostatic unit), and the other is the metal part or valve body. 

The upper cap or shelter is the ‘thermostatic head’; other parts are installed inside it. A ‘thermal element’ or ‘sensor’ is also installed to sense the temperature of the water. Besides, a ‘heat resistant molding’ is present there. 

You may see some numbers or symbols on this unit. These numbers represent how much heat the radiator is delivering right now. It has a level between 1-5/6 (vary on models). You can follow the box with that valve to know which level produces how much heat.

Now, come to the valve body. On the up, there is a ‘thermostat removal nut.’ This nut joins the valve head and body together. If you undo this nut, the head will disassemble from the valve, and you’ll see a ‘pin.’ The valve probably has two inlets, one for the heat source and the other for the radiator

A ‘connecting nut’ connects the pipe and valve on the heat source inlet. Similarly, on the radiator inlet, there’s a ‘radiator securing nut’… that ensures the bond between the valve and the radiator.

trv valve
TRV valve

How Does a Radiator Valve Work

All radiator valve controls the hot water supply into the radiator to keep the balancing temperature in your room. However, it looks small… but it’s a mighty device that controls everything on your radiators.

As you know, radiator valves have two inlets. One inlet connects the valve with your heat source or boiler, and the other links with the radiator. Hot water comes to the valve from the heat source through the copper or plastic pipes. After that, hot water enters the radiator.

The radiator valve senses the temperature through the thermostatic element. When the hot water comes and tries to enter the valve, it measures the room’s temperature… if it’s hot out there, the valve head pushes the pin down and shuts off the valve until the cold temperature is down

On the other hand, it lets the hot water in if it’s cold and needs heat. After that, when the room reaches the desired temperature, TRV will again close the hot water supply.

Some people get confused over the indicator number on the radiator valve. Most radiator valves are set to 20℃ when the number is set to 3. Each number has a 4/5℃ difference (depending on the valve model and manufacturer). 

From dereton33

Buying Guide

When you buy radiators, there’s no valve included. It’s because there is no one-size-fits-all solution… every home and lifestyle has its texture. So, before purchasing radiator valves, consider the size, shape, and finish that suits you. Also, radiator valves come with different structures like straight, angled, and H-block. Depending on your pipework and radiator, you must choose the perfect fit. For a clear idea, follow the types table below:

Radiator Inlet

Pipework Through Wall

Pipework Through Floor


Angled Radiator valve

Straight Radiator valve







If you’re still confused, then don’t hesitate to contact Plumberstar. Plumberstar will listen to your problem and provide a better solution with a suitable radiator valve.

Things to Remember

Remember and follow these things to get a better experience using thermostatic radiator valves:

· Don’t attach a TRV to a radiator in a room if there’s already a wall-mounted thermostat. Therefore, they’ll fight together to heat the room.

· Don’t install a TRV in bathrooms or shower rooms. It’ll get confused about the extra heat of the shower or bath.

· Check them at least once or twice a year to ensure they’re working well.

· To get better performance of TRVs, don’t forget to check the heating systems.

To Sum Up

In short, installing new radiators is a great way to increase your heating system’s comfort and energy efficiency. However, the radiator valves you choose will have a significant impact on the performance of your radiator.

Buy radiator valves from Plumberstar to get the latest, best-matching, and top-quality products. In addition, there are all types of brass valves available in Plumberstar. So, what are you waiting for? Go and grab yours because they are not just valves. They are your comfort and happiness.

radiator valve test
radiator valve test

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