Is your lockshield valve leaking? Here we detail the common causes and how to resolve them.
There are several ways in which a radiator might leak.
For example, it might occur due to worn down metal on the radiator base or perhaps from a faulty thermostat radiator valve.
But what about a leaking radiator lockshield valve?
In the following guide, we’ll discuss what causes a lockshield valve to leak and what you can do about it.
Let’s begin!
What is a Lockshield Valve?
A lockshield valve is a key component of a radiator.
It’s designed to control the level of water that either stays in or flows out of a radiator.
You should be able to find a lockshield valve on the side opposite the on/off valve.
It will also feature a cover, which will generally come in the form of a white plastic cap.
If you’re having trouble finding it, take a look at the manufacturer’s instructions.
Which Part of Your Lockshield Valve is Leaking?
To fix a leaking lockshield valve you will first need to determine which part of the lockshield valve is the actual source of the leak.
There are several possibilities, namely, a leak with the packing nut, a leak at the valve to the radiator section or a leak at the pipework to the valve area.
If you want to determine the source of the leak, you should try the following steps:
Ensure you’ve turned off the heating and that your radiator is off. Also do double-check that it isn’t time to come on while you’ll be working on the valve per your heating schedule (e.g., the heating schedule on your thermostat).
Turn off the lockshield valve before removing the white cap atop it. If you have an older radiator, you may need to also remove a screw.
Next, give the entire valve a good dry.
Once you’ve dried the entire area, you may want to wrap a dry piece of kitchen towel paper around the valve and see which area first becomes damp. Be sure when removing the kitchen towel paper that no bits of paper get stuck anywhere on the valve.
By now, it should be obvious where the leak is coming from. However, it’s important to be aware that if the packing nut is the source of the leak, it will drip water along the side of the lockshield valve. Generally, this water will pool at the nut beneath which can give the false perception that the leak is coming from below. All in all, it’s important to analyse things carefully and double and triple-check the source of the leak before continuing.
What will you need?
Note: If you are unsure about any aspect of fixing a lockshield valve leakage, hire a professional plumber.
Also, if you do attempt this working DIY, be sure to follow the manufacturer’s instructions.
Of course, the steps provided below will help give you a clear sense of what’s involved, however, using the official instructions will help with any specific details.
In general, you will need at least some of the following materials:
Bradel
Screwdriver
A towel
Several sheets of kitchen towel paper
Pair of grips
Dowel
Adjustable spanner
PFTE tape
Bucket
Large bowl
Pipe freeze kit
How to Fix a Leaking Lockshield Valve
If The Packing Nut is Leaking
Note: Be sure to turn off your heating and let your radiator cool before proceeding.
The most likely explanation behind a leaking lockshield valve is that it is coming from the packing nut.
After all, this component is particularly susceptible to wear and tear over time.
This nut sits at the top of the valve and is generally covered by a white plastic cap (or a similar type of cover).
The packing nut works to ensure there is a watertight seal around the moving components of the lockshield valve.
It achieves this by tightening up against the rubber washer. With that said, how can you fix a leaking packing nut?
Tighten the Packing Nut
It’s easy to overlook the possibility that the packing nut simply needs to be tightened.
Tightening the packing nut may solve the leak just like that. However, if this doesn’t bring any success, move on to the steps below.
Repack the Nut
While it may turn out that the packing nut needs replacing if tightening it doesn’t work there is still one other approach worth trying.
Please be aware that you may need to try and retry this approach a few times before it succeeds.
This is because it might be difficult to judge exactly how much PFTE tape will be needed on your first attempt.
The first part of this method involves removing the packing nut per the manufacturer’s instructions.
Upon removing the nut, you should notice that it’s wet.
Moreover, the part within the lockshield valve where the leaking water is emerging from (i.e., inside the stem) will now be visible.
You should have a clear idea as to how the water has travelled up via the stem in order to leak out.
Once you’ve removed the packing nut, it’s time to repack it.
As touched on earlier, the packing nut keeps the washer in place in order to provide the lockshield valve with a watertight seal.
However, washers are not designed to be removed or replaced.
Therefore, you’ll need to employ PTFE tape in order to repack the valve. Here is what’s required:
Break off approximately six to eight inches of PFTE tape.
Next, you’ll want to twist it in order to create a thin string-like segment.
Then wrap the exposed stem with the piece of string-like PFTE tape. Be sure not to wrap the tape around it too tightly. However, it shouldn’t be loose enough to allow a gap either. It’s important to get it just right!
Get a hand of the bradel and poke the segment of PTFE tape down and into the small chamber that can be found at the base of the stem.
Once you’ve completed the steps listed above, put the packing nut back into position, tightening it appropriately.
When you next try to turn on the lockshield valve, it will hopefully work as planned. However, it is possible that you have not added enough PFTE tape.
If the valve spins easier than it should, it may mean that you’ll need to remove the existing tape and add a fresh but larger segment to wrap around the stem and into the chamber.
If you cannot get it to work, you should hire a professional. It’s also, of course, possible that the packing nut really needs replacing.
Swap out the Packing Nut for a New One
If the packing nut appears to be completely worn down or the first or second approaches simply won’t work, you should have it replaced with a new packing nut.
You could do this yourself if you feel confident about the task.
However, if not, again, get in touch with a professional plumber.
What if There is a Leak in the Pipework to the Valve Area?
Note: Be sure to turn off your heating and let your radiator cool before proceeding.
Another possibility is that the leak is occurring at the union nut connecting the pipework and lockshield valve.
There is a several-step process that you may want to undertake DIY to address this, however, unfortunately, in many cases, these steps will not succeed.
If in doubt or if your attempt fails, call out a professional plumber to come by and fix the issue.
Tighten the Union Nut
Again, before assuming that there is a complex explanation for the leak, tightening the relevant nut may suffice.
In this case, you would need to try tightening the union nut.
In order to tighten a union nut, use the grips and hold on to the valve carefully to keep it in place.
Try to be as steady as possible because if the valve were to move while being tightened, this could result in the seal at the other joint breaking which would only create another headache.
So, if you find that the leak worsens while you’re tightening the union nut, you should stop right away.
Bleed Your Radiator, Freeze the Pipe Below and Undo/Redo the Union Nut
If simply tightening the nut does not work, there’s another method worth exploring. The first step of this approach involves bleeding your radiator.
Please follow the manufacturer’s instructions for this part of the process, however, you might also want to check out our guide to radiator bleeding.
Our guide will give you a solid overview of what’s involved.
Next, it’s time to free the pipe that can be found below the lockshield valve.
The purpose of this is to ensure that this live pipe is frozen before undoing the union nut.
You can buy a pipe-freezing kit to undertake this DIY if you feel confident you know what’s involved and that you have the right skills.
Please follow the manufacturer’s instructions to a T. If in doubt, hire a professional.
More than likely, you’ll need to hire a professional as this job can get pretty complicated and may not even work.
Ensuring that you’ve turned the lockshield valve off and frozen the pipe correctly, you can move on to undoing the union nut.
Double-check where the olive is placed. If you find it at the very end of the pipe, you should consider replacing it.
However, if the olive seems in sufficient shape, take eight inches of PFTE tape (twisting it up into a string-like segment) before wrapping it around the end of the pipe.
Finally, redo the union nut, defrost the pipe below the lockshield valve and, of course, repressurise your system.
To repressurise the system you should primarily follow the manufacturer’s instructions, however, you can also take a look at our guide to repressurising a boiler.
What to Do About a Leak at the Valve to Radiator Area?
Alternatively, there may be a leak at the union nut connecting the lockshield valve to the radiator.
This is, of course, a separate union nut from the one connecting the pipework to the valve area.
Tighten the Union Nut
In this case, you’ll first want to try tightening the union nut. To do this place the grips on the nut while holding the valve steady.
Try to be as steady as you can because if the valve were to move while you’re tightening the union nut, the seal at the other joint may break loose, only worsening the issue.
Moreover, as you are tightening the nut, if you notice the leak getting worse, stop right away.
Empty Your Radiator and Pack the Joint
If tightening the union nut does not stop the leak, here is another potential solution. This several-step approach first involves emptying your radiator.
While making sure that each of your radiators is off (and making sure your heating isn’t scheduled to turn on), you’ll need to prepare a bowl and bucket before loosening off the union nut that connects the valve and radiator.
Next, undo the radiator bleed valve. This will allow air to reach the top of the radiator and by extension enable the water at the bottom of the radiator to spill out quicker.
Use the bowl to catch the water and then pour that water from the bowl into the bucket as you go, placing the bowl back in place right away to catch more water.
You’ll also want a towel beneath the bowl to catch excess water. Keep going until water stops coming out of the radiator.
You can now move on to the next step, packing the joint.
To know how to proceed, you’ll need to take the location of the olive into account.
If you find the olive at the very end of the tubing beneath the nut, you should have it replaced with a fresh olive.
However, if the olive is instead recessed as far back onto the pipe as possible, you can try wrapping it in PFTE tape.
Pull off approximately eight inches of PFTE tape and twist it into a long string-like segment.
Wrap the exposed end of the pipe beside the olive in this PFTE tape segment.
Lastly, tighten the nut back into position. Hold the valve carefully as you retighten in.
Again, you do not want to break the seal on the other joint. And with that, you’re done!
Hiring a Professional to Fix a Lockshield Valve Leak
If you are unsure how to undertake this working DIY or have no success in your DIY attempts, you can always hire a professional.
On average it costs somewhere between £30 and £60 per hour to have a professional plumber undertake a given task.
Moreover, labour prices differ throughout the UK with prices generally being higher in the southeast of England and lower in regions like northern England, Scotland and Northern Ireland.
Of course, in many cases, supply costs will be added leaving with you a higher cost overall.
The cost of hiring a professional to fix a lockshield valve:
Fixing a leak at the packing nut - £35 to £195
Fixing a leak at the pipework to valve union nut - £35 to £195
Fixing a leak at the valve to the radiator union nut - £35 to £195
Replace a broken radiator - £230 to £320
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