Unusual radiator lockshield valve

[milleniumaire]

Hi guys, I'm sure this isn't unsual to you, but as 90% of the radiators in my home have 15mm valve fittings on both sides (flow and return) it is a little confusing for me.

Around 15 years ago a couple of radiators were installed in a loft extension and I'm currently trying to unblock the pipes that feed these (that's another thread I have already posted). The lockshield valve of these two radiators appears to have a 22mm connection to the radiator. So, from what I can see, one side of the radiator has a 15mm connection and the other side a 22mm connection. This seems strange to me. Here's a photo of the lockshield valve:

The other valve (flow) uses a 15mm connection to the radiator.

I want to be able to connect the following JG speedfit hose connection to each valve in turn:

This will allow me to connect a hose and force water through the valve/pipework. The other end of the pipe will collect the water in a bucket.

I have connected this fitting to the 15mm valve using a piece of copper pipe and an olive/spare nut to screw it onto the valve. Haven't tested it yet, so not sure if this will be water tight due to the limited thread on the valve.

My issue is how to do the same on the other (lockshield) valve as it is 22mm!

Any thoughts would be appreciated.

 

[Brambles]

Throw it away. Fit a 15mm tails to the radiator - which will be a male 3/4” connection into the female radiator core - thereafter fit standard 15mm Thermostatic valves.

 

[milleniumaire]

Throw it away. Fit a 15mm tails to the radiator - which will be a male 3/4” connection into the female radiator core - thereafter fit standard 15mm Thermostatic valves.

Thanks for getting back to me Brambles, and in less than a minute! What a great forum 🙂

I confess, I had considered changing the lockshield valve, but I wasn't sure if this 22mm valve had been used because the radiator needed that type of fitting, as the connection into the radiator also seems to be wider than the usual 15mm.

Here's the side of the radiator that takes the standard 15mm TRV valve:

And here's the other side of the radiator that has the "non standard" 22mm lockshield valve:

My finger nail attempts to provide a scale.

As you can see, on the 22mm side the female fitting into the radiator seems to be much bigger, so I'm not sure if that is what dictates the use of this size of fitting!

I'm also not sure how to get this fitting out as there doesn't appear to be any room between the nut and the radiator to get a spanner in.

 

[Brambles]

A hexagonal radiator wrench slides into the fitting for removal.

 

[centralheatking]

A hexagonal radiator wrench slides into the fitting for removal.

or an allen key ...same thing. chking

 

[snowhead]

That's not a 22mm lockshield , it's 15mm / 1/2" valve with what used to be standard for rad valves a 3/4" union.

 

[milleniumaire]

That's not a 22mm lockshield , it's 15mm / 1/2" valve with what used to be standard for rad valves a 3/4" union.

Do these tend not to be used any more? It seems strange to have two different "union" sizes on each side of the radiator. I assume these can be changed or is this dictated by the bore in the radiator?

 

[Brambles]

It is an old type of fitting. This is a good opportunity to clean out the radiator, fit new tails and 15mm thermostatic valves - just in time for the first frosts.

The “bore” of the radiator is the same at either end, it is only the locknuts that are of different sizes - one for the valve and the other for the lockshield.

However, fit two new tails to the radiator, followed by a new 15mm valve set. Don’t try to reuse the old 15mm rad tail.

If you are flushing the pipework with a hose, probably best to remove the valves and connect the hoses directly to the pipe up stands first. Don’t flush through new valves.

 

[ShaunCorbs]

The 3/4 15mm Lockshield valve

If you want to flush the system pull the tail out of the rad via an plumbers Allen key

Then a 1/2 female iron on the end of the tail or a 1/2 hose connection

I like that type of Lockshield valve for the reason you can remove the rad easy enough the problem with the 15mm ones is that you have to spring the pipe apart to get one side out

 

[Best]

To connect a hose to a 3/4" tail rad valve you could remove the tail from radiator (using appropriate Allen key tool) and temporary screw on to the 1/2" threads a 1/2"X15mm female fitting using ptfe tape and connect tail 3/4" nut to rad valve.
Tighten a piece of 15mm into the female fitting and use a jubilee clip on a hose

 

[milleniumaire]

Thanks all for the feedback.

I had another go at flushing through last night, but the water is still only trickling through, so the pipe run I'm currently working on is still obviously blocked. After I poured out the water from the bucket, I was surprised to see this:

This is from only one pipe run of the 6 I have to flush!

Although I've flushed through one of the radiators outside, I may replace them both as they are around 15 years old. Not sure what to do about the chrome towel rail. I assume these can also corrode on the inside?

Not sure if this sludge in the loft pipes is purely from the loft radiators or if it will be from the whole house, but will have settled in the loft pipes due to the poor flow.

This amount of sludge explains why the radiators in the loft aren't warming up!
[automerge]1572369329[/automerge]
Oops, sorry I meant to post the above on my original post:

Cold radiators in loft

 

[milleniumaire]

Thanks for the responses to my question, I thought I would give a final update.

While trying to clear the pipes of sludge by flushing through water at mains pressure, I realised (as mentioned by Brambles) that the radiator valves were actually clogging up and slowing things down. I therefore removed both valves and connected a couple of full bore isolation valves to the radiator tails using the remaining valve nut and olive. Onto the other end of the isolation valve I attached a short piece of copper, then pushed the speedfit hose connector onto the end of this. I attached a hose to each of these connectors; one hose was connected to the outside tap and the other hose terminated in a bucket.

This setup allowed me to turn on the outside tap and then use the isolation valves to stop/start water going through the pipes. Eventually the water ran clear.

I then fitted a new 0.5" lockshield valve, which required replacing the olive on the radiator tail and re-installed the flushed through radiator. Finally connected the hose pipes to the ends of the pipes feeding the radiator so I was able to push mains water through a final few times to ensure the pipes and the radiator were clear of sludge. This also allowed me to check the water tightness of the valves.

The pipe for this radiator was then connected back up to the loft supply and return pipes and everything is currently working perfectly. This radiator, which hasn't had any heat in it for over a year, now heats up brilliantly.

I now have a towel rail and another radiator to do, but have a system so hopefully it won't be too much work to get these cleaned out.

It has really surprised/worried me exactly how much sludge has accumulated in these pipes and radiator. Once I've completed this task (and at some point replaced the 15mm pipes upto the loft with 22mm pipes) I will go through the process of cleaning out/flushing through the whole CH system.