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Radiator Leak – How to Diagnose and Fix the Problem in No Time

A woman dealing with a radiator leak

Many things can go belly-up, ruining the comfort of your home, but so few can be as unpleasant as finding a wet patch or a puddle of water next to your radiator. If that happens, you have to be swift to prevent any damage to your floor and furnishings, such as cupping or crowning.

Fortunately, we’re here to help so that you won’t be handling the issue all by yourself. Follow along to find out how to stop a radiator leak and even learn some ways to prevent it.

Determine the Source of The Leak

To collect as much water as you can, place some towels or old rags on the floor around the radiator and have a bucket ready to use. Now you can relax for a bit, and since radiator leaks can come from a variety of different parts, you will need to locate the exact spot of your leak. That could be anything from a loose joint to a small pinhole in your radiator body.

Take a towel or an old rag and dry every part of your unit, but watch out if it’s turned on, cause you risk burning yourself. Drying out your radiator will give you the chance to investigate and eventually find the water leak easily. 

The next step is to take some toilet paper and wipe all parts one by one to see if the paper gets wet. Besides the body of your appliance, investigate all the fixtures, such as pipes, joints, and valves. Naturally, the component of the radiator that drenches the toilet paper is the culprit behind the leak.

Here’s How to Fix a Leaking Radiator

It’s time to repair your leaking radiator now that you know where the leak is coming from. So, roll up your sleeves for some DIY maintenance work and be ready to get your hands dirty. We’ll discuss some parts of your radiator that can leak, shed some light on why this happens, and give you an idea on how to fix it.

How to fix a leaking radiator valve

The valve leaking in a ‘mid-open” position typically happens because the spindle packing, found inside, wears out with time or gets damaged for some reason. Fret not, though, because one of the simplest things to put right is undoubtedly a radiator valve leak.

In this scenario, the leak usually ceases when you close your valve entirely, and that would give you some time to replace it by yourself or call an expert to help you out. If it doesn’t stop, though, then take these steps:

Step 1. Discharge any water

To patch your leaking valve, first, you’ll need to drain the water out of your unit to a point below the leak. That way, you’ll prevent more water from escaping your radiator.

Step 2. Cut the water supply

Turn your water supply valve off to stop your radiator from filling while you work on it.

Step 3. Turn your lockshield valve

The lockshield valve’s purpose is to balance your radiators within the entire heating system of your home. It’s located at the other end of your radiator and usually has a white plastic top.

Turn the lockshield valve, but note how many turns it takes to close it altogether, as you’ll need to adjust it back the same way once you’re done. And if by any chance your valve has a screw on the top, use a screwdriver to loosen it, until you feel that you can freely turn the device.

Step 4. Prepare the area

To stop any additional leaks during the repair, make sure you have the towels and bucket ready. Also, grab an adjustable spanner and brace for the upcoming task.

Step 5. Untighten the union nut

Carefully undo the union nut that attaches the radiator and the supply pipe, using the adjustable spanner that you have prepared. And if it’s tough to budge, make sure you use grips on the valve itself to stop it from moving.

Step 6. Bleed your radiators

To prevent injuries by scalding water, first, turn off the heating system and let it cool for a while. Allow the rest of the water to leave the appliance by opening the bleed valve, the one on the top right of your radiator. 

Don’t forget to place the bucket below the device, so you won’t have to deal with a brand new puddle of water. You can bleed the valve with a bleed key, but if you don’t have it, keep calm and use a screwdriver to loosen the pluck.

Step 7. Wrap the valve with PTFE

Wrap some PTFE tape or also known as “plumber’s tape” 10 to 20 times around the valve tail, at the male end of the fixture. That way you will seal the leak and hopefully patch it until you buy a replacement valve.

Step 7. Tighten the union nut and start your water

Re-tighten the union nut and open the water supply valve to fill the heater.

Step 8. Open the lockshield valve and test

Remember the lockshield valve? What about the number of times you’ve turned it? Well, it’s time to open it to the point it was before. When done, check how the radiator operates and see if the leak persists.

Hopefully, that works, but you may have to replace the radiator valve if it doesn’t. To figure out how to proceed, read more.

How to change your radiator valve

As people say, better be safe than sorry, so you might want to replace the valve entirely to avoid a leak from reoccurring. Although, when buying the new valve, make sure to get the same type as the old one, as it has to fit perfectly to the water pipe.

Replacing the valve may seem like a daunting task, so you might want to consider calling a professional to carry it out for you. Otherwise, if you feel like a DIY enthusiast, you can quickly learn how to change a radiator valve.

Radiator leaking from couplings and pipes

You may also find that the leak is in the pipes and couplings of the radiator. If you spot one, before attempting to fix it, you’ll have to turn the appliance off and allow it to cool for a bit. That way, you can work more safely, and you won’t have much trouble untightening the fixtures, as they’ll shrink when the heat reduces.

A leaking radiator valve spindle

The spindle is a small fixture, part of your radiator valve; it connects the pipework and the appliance, and when damaged, it may be the fundamental cause of a leak. Fortunately, you can efficiently deal with that issue, so follow those steps:

  • First, carefully remove the plastic valve cap of your valve.
  • Try to tighten up your gland nut with an adjustable spanner. You can find it right below the spindle.
  • See if the leak still occurs and if it does, loosen the gland nut instead.
  • Wrap a fair amount of PTFE tape around the spindle and try to push the tape into the body of the coupling.
  • Tighten the gland nut once again and test the radiator.

Yey, if this doesn’t solve your problem, consider changing your valve with a new one.

A leak from the gland nut

Sometimes, you can patch a radiator leak by merely re-tightening the radiator valve gland nut. But if that fails, you’ll most likely need to replace the olive within the coupling. 

  • Before you begin, turn your heating system off and cut your water supply.
  • Next, unfasten the nut that connects your radiator and the leaking pipe, but make sure to have towels and a bucket ready, as you’ll have to collect some water.
  • Then completely remove the nut and its fitting from the tubing.
  • Now try to detach the uncovered olive and prepare the new one for fitting.
  • Wrap it with a bit of PTFE tape before back in place.

Pro tip: We recommend changing the entire radiator valve for your peace of mind.

A leaking pipe joint

Leaks may take place when the pipe joints loosen or get worn out. Although, you’ll have a set of those joints that link the pipes to your radiator only if you have a compression heating system.

See if you can tighten up those fixtures with an adjustable spanner. Usually, that stops the leak, but if it doesn’t, check out this quick solution:

  • Turn off your heating system and cut the water supply to your radiator.
  • Drain the water out of your appliance to a point below the source of the leak.
  • Untighten the joint nut with an adjustable spanner and try to detach the leaking pipe.
  • Wrap around 20 cm of PTFE tape around the area where the face of the olive crosses the joint.
  • Tighten the nut again, but don’t overdo it, as you may damage your couplings.

How to fix a pinhole leak in a central heating radiator

Corrosion is a bad sign for all types of appliances. In fact, that’s one of the main reasons for a radiator body leak, or in short a “pinhole leak”. Unfortunately, we have some bad news.

Corrosion triggers this sort of leak because sizable black sludge deposit causes the rust spots within the body of your appliance. Your best bet in this situation is to change your radiator completely; however, if you aren’t using a sealed central heating system, then we might have a quick solution.

  • Before you do anything, make sure that you have a feed and expansion tank, and not a sealed system. Consult with a Corgi registered plumber near you if you have any questions regarding the type of your system.
  • To stop the leak, cautiously apply a plastic resin sealant.
  • Start looking for a new radiator, because that fix might not last for as long as you wish.

And if your radiator is still leaking?

Despite any temporary solutions you might try, your radiator may be corroding, or a persistent leak can still occur. If that happens, you will have to consider getting your unit checked and even replaced. But to remove a radiator is easier said than done, not to mention the process of installing a brand new appliance. 

We’d recommend that you call a professional heating engineer for your radiator installation, as they guarantee for a service well-done, with no mess left behind.

How to Prevent Radiator Leaks

Whether you have your old radiator repaired, or you’ve bought a new sparkling appliance, the thought of another leak is unnerving. To avoid such disasters from reoccurring again, use a rust and corrosion inhibitor and a radiator cleaner regularly.

Don’t forget to investigate any signs of failure in the pipe connections and fixtures that link the radiator to your central heating system. Early detection of issues will help you avoid more costly repairs.

Key Takeaways

It is an irritating issue to find water leaking from your radiator, but it’s easier to repair it than you possibly thought. A defective radiator valve can often be the culprit, but make sure to check out the radiator’s couplings and small fixtures. And if luck isn’t on your hand, it’s more probable that you’re dealing with a pinhole leak due to corrosion. 

Think of the cost and time before doing any DIY repairs or installation, as a competent heating service may be a safer option.

Radiator Leak – How to Diagnose and Fix the Problem in No Time

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