Radiator Valve Stuck: How to Unstick it

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Key Takeaways
  • A radiator valve can get stuck when the pin that starts the mechanism fails to move. To fix this, you need to remove the valve head to gain access to the pin.
  • Apply enough pressure on it until it springs back to its original position.
  • If this method does not work, tap the valve until the pin dislodges.
  • If all else fails it’s best to call a professional.

Winter is finally here (at least somewhere in the world!). It’s time to turn the heating on in your home and get toasty and comfortable. But for some reason, the radiator’s not getting hot enough?

The most common culprit for malfunctioning radiators is not the radiator itself. Most of the time, the radiator valve gets stuck and doesn’t work correctly. In this article, we will learn how to fix a stuck radiator valve.

It is relatively easy even for users without a plumbing background, but if your nervous about making a mistake it’s best to call a professional.

What is a Thermostatic Radiator Valve? 

The Thermostatic Radiator Valve or the TRV is a useful component in every HVAC system. It is used on water-based radiators to control the temperature of a room or a particular space. What it does is it changes the flow of hot water that goes through the radiator. Flowing hot water keeps the area warm. The radiator valve detects temperature and redirects water flow to places where it is needed the most. 

Radiator valves can also keep different rooms at different temperatures. It enables the user to create custom temperature settings between rooms and parts of the house. So if you only want to heat a specific area (or vice versa), you can do so just by turning the radiator valve.

It truly is a handy device, but it can also be a pain in the neck when it gets stuck. 

Why does it get Stuck? 

Since the radiator only controls the heating, the radiator valve stays turned off during the warmer seasons. There is a plunger inside that springs up the pin, which starts up the whole mechanism. But because it has been in the “off” position for quite some time, it might not move. 

When this happens, even if you cranked up the valve to the highest settings, the radiator will not work (or will not flow in the area it covers). Most users who are not aware of this will immediately assume that the radiator is the problem.

Before trying everything else, check your radiator valve first, especially if the radiator itself can still regulate the heat in other rooms.  

How do you Unstick a Radiator Valve? 

Fortunately, fixing a radiator valve is relatively easy and doable in less than an hour. You can do it at home without special equipment and technical knowledge in plumbing.

Take note: If your radiator valve is fine and working, you might have a bigger problem with your system. In this case, it is better to get professional help. 

Materials you need

Here are the materials you would need to unstick a stuck radiator valve.

  • Water pump pliers
  • A flat piece of metal
  • Lubricant spray (for corroded valve seat)

The lubricant spray is only needed if there is corrosion in your valve pin. You can use any flat object, but a flat metal is ideal because it does not break when pressure is applied. Ensure that your valve is in the max option (the arrow should be on five or the dark circle). 

Repairing a radiator heater valve

Step 1. Twist the locking nut until you’ve freed the thermostat

In most products, the locking nut is a metal ring around the valve seat. Use your water pump pliers to turn the locking nut. Clip the pliers to the locking nut and turn it counter-clockwise. Do this until you can turn the locking nut using your fingers. Pull the thermostat off. 

Other products would have different locking mechanisms. A popular one uses black pins,  in which you need to pull it out to release the lock. Once this is performed, you can pull the thermostat out easily. Refer to your manual radiator valve manual for specific instructions. 

Step 2. Check if the pin is embedded deeply to the valve head

After removing the thermostat, you should see a component that looks like a receptionists doorbell. That is the pin that jumpstarts the mechanism. But if it is embedded in the valve head, it gets stuck and is hard to move.  A stuck radiator valve pin will look like a pressed button that doesn’t get back once released. 

One of the possible reasons why a radiator valve gets stuck is rust formation. Examine the surroundings of the pin to see if this is the case. Clean the surroundings of any dirt, if there is any, and apply a lubricant like WD-40 spray to loosen up the corroded parts. 

Step 3. Apply pressure to the pin using some flat metal

Get some flat metal and put its center part above the pin. Use your fingers to apply force from either side of the flat metal. Do this repeatedly until the pin is released and the plunger inside is unstuck. If you don’t have any flat metal, you can use your water pump pliers to tap into the pin gently. Don’t use excessive force, or you might destroy the valve head accidentally. 

When done correctly, the pin should spring up and doesn’t look like a pressed button anymore. It is worth noting that the pin is not the component that gets stuck, but the plunger inside the valve seat. 

If the pin doesn’t move

There are times when the plunger in the valve head is stuck firmly inside. Applying pressure to the pin might not work anymore. Before giving up, try to apply pressure to the pin several times before resorting to the next step. 

The next best available option is to get your water pump pliers and make a sharp tap at the sides of the valve. It creates shocks that dislodge the plunger. Avoid hitting the pin or leaving a dent in the surrounding metal plate. Just wack it gently until the pin would spring up. You might want to give occasional press to the pin to help the plunger move. 

Don’t use the pliers to pick the pin

No matter how stubborn your pin might be, do not use the pliers to pick up the pin. Pulling the pin off the valve will not release the malfunctioning plunger. Instead, the pin gets ripped off the mechanism. It creates a bigger problem than just a stuck plunger, so don’t do it. Just continue tapping the valve and pressing on the pin until it is dislodged completely. 

How do you know if the valve plunger is successful unstuck?

You should be able to check if the repair was successful if you started feeling hot water running into the valve. It will then come into the return side of the radiator. Now that the main problem is solved, the next thing to do is get things back to where it should be. 

Step 4. Put the thermostat and the locking nut back

To put the thermostat back, check where the arrow of the thermostat is facing. Since we want to be able to use the thermostat properly, make sure that the arrow is pointing in front. Connect the valve and the thermostat and turn the locking nut clockwise (or put the black pin back if you don’t have a rotating locking nut). Give a final push to the locking nut using the water pump wrench to secure the thermostat to its place. 

Now that the thermostat is in the right place, you might be tempted to turn it off to test if everything is okay with the thermostat.

DO NOT turn the valve OFF. Just let it sit for a while so that the plunger will get used to the position. While the system is heating, it will lubricate the valve, preventing it from being stuck again in the “OFF” position. Leave it for a day or two, and then turn it off if you want to. 

This guide is only for fixing stuck radiator valves. In most cases, it can solve the problem of radiators that don’t turn on. Call a plumbing expert if the problem persists after you’ve tried fixing it or if the pin seems to be working fine after opening the valve. 

If you are not confident about fixing the valve yourself, contact a professional and avoid the risk of injury or of breaking any components.