Draining a radiator for removal - my MkII gizmo

[Set Square]

In an earlier thread, I described a device which I had made to enable a radiator to be drained prior to removal by pumping air in through the bleed hole - thus pushing the contents up into the F&E tank (in a vented system only, of course) rather than spilling it all over the carpet.

The device consisted of a Schrader valve from a car tyre, soldered into a

1/8" BSP fitting which could be screwed into the radiator in place of the bleed assembly.

However, not all radiators have a a removeable bleed assembly. Some rolled-top rads, such as

have the bleed housing integral with the rad, with only the central pin being removeable. My devise couldn't be used with such rads. [The rad in the picture has been outside in the weather for a couple of years - it isn't one of my best ones!]

I have done a bit more research on bleed pins, and all of mine - regardless of whether the bleed housing is removeable or integral - seem to have a 2BA thread. I have now modified my gizmo so that it has a 2BA end to screw into a radiator in place of the pin rather than in place of the assembly. To do this, I found a 2BA bolt about 1" long and drilled a 1/16" hole through the centre of its long axis (pillar drill essential for this!), and then cut the head off. The bottom end of the Schrader valve, below the works had enough length, and was just big enough in diameter to allow me to tap a 2BA thread in it, enabling my drilled headless 2BA bolt to the screwed in. The revised gizmo now looks like this (with the larger 1/8" BSP fitting surrounding it now being redundant)

the bit which screws into the radiator should have a shaped end - like the original bleed pin - to fit the conical seat in the housing. In the absence of a model-maker's lathe, I couldn't do this, but it seals well enough - albeit not perfectly - on the threads with the use of a bit of PTFE tape. Here it is when fitted to a radiator. anyone thinks that such a device would be useful, feel free to copy or improve on the idea.

[I still have *one* rad on which I can't use it. It has the bleed screw on the *back* rather than the end!]

[Ian Stirling]

Alternatively, if you've got a wet/dry cleaner, you can switch it into wet mode, turn it on, then loosen the nuts to allow water to flow out and be instantly sucked sideways.

[Rob Graham]

I didn't see the earlier thread which no doubt had much the same comment of how do you get the gizmo in place without getting water all over the place from the bleed hole, but then realised that if the radiator is isolated first then of course there's no pressure !!

Having watched with some amusement my daughter's partner struggle with a CH system refill after changing a radiator (it's quite good when you are older and have seen much of it and watch the next generation going up the same learning curve!), I can well appreciate that this device could be worth making. I do have the tools - a lathe will be even better for drilling the 2BA rod - but do wonder whether the time making the device might exceed the time doing a quick drain down and refill. One thing that it would be a boon for is removing radiators when re-decorating though and for that alone I think I will look at making one.

Thanks

Rob

[Set Square]

That's right. If you turn off both valves, you can remove the bleed pin without spilling any water. It best to pump air in with the valves shut, too - and then crack open a valve and listen to the water being expelled. It usually takes several goes. You can tell when the rad is empty - because the last slug of water/air mixture makes a very rude noise as it passes through the valve!

That's precisely what I use it for. It's less useful if the whole system is being drained. It may take an hour or two to make - but you've then got it for ever, unless you lose it!

[N. Thornton]

Nice one. How bout using a drill as the lathe? An angle grinder makes an effective cutting/grinding tool, conventional tools arent much good on a holderless drill lathe.

NT

[Set Square]

Possibly. I did rotate the 2BA bolt in a drill chuck, and tried to file a conical shape on the end - but it wasn't very successful. If you look at the picture of the original bleed pin, it has quite a complex profile as it approaches the sharp end - I don't how accurately this would need to be replicated for it to seal on the conical seat. For example, if the hole in the rad reduces in diameter near the conical seat, my 2BA thingy wouldn't actually reach the seat unless that did the same. So I settled for sealing on the threads instead.

[Andy Wade]

But you can't start the process that way as the air's got nowhere to go (unless you attach an external pressure vessel, which would seem a little OTT).

What do you use for your air supply? - Foot pump, compressor, ...?

I'm just wondering whether this might be a good way of disturbing the sludge, which inevitably collects at the bottom of every radiator, and distributing it round the system. That would certainly be a Bad Thing.

Nice idea though.

[Set Square]

In my experience, there's always *some* air in the top of a radiator, even when bled, because the bleed screw isn't at the highest point. So you compress this to start with, and then have more to go at once you have expelled some of the water.

Foot pump, operated by hand.

I've never experienced any problems due to this. I think most of the sludge stays in the rad. You certainly get some coming out when you upend the rad, having removed it. [You still have to be careful to collect any remaining water/sludge when undoing the unions - but it's much easier than undoing them with the rad full of water].

[Christian McArdle]

Call me boring, but I just fit draincock type lockshields, so you just isolate the rad, attach hose, turn the tap and open the bleed valve. Radiator drained in 2 minutes and not a drop on the floor.

Christian.

[Set Square]

I think they're a brilliant idea - but I don't have them at the moment, and can't think of a way of fitting them without draining the rads in some other way to start with!

Is it fair to assume that they're longer than standard tails - and so require some pipework adjustments if they're retro-fitted?

[Christian McArdle]

Well, I did the whole lot at the same time, so the whole system was drained down. No need to drain individual radiators then.

Nope. Mine were identical to non-draincock types in terms of geometry. The main problem with them is that they stick out the other way more, which some (i.e. those who aren't responsible for removing radiators) may find aesthetically challenging.

Christian.

[Andy Hall]

You can set the tail so that the hose tail is horizontal, outlet towards the back.

They are a bit less conspicuous if seen from across the room.and you can still get the hose onto them.

Ultimately, though, you have to stick up for your rights and remind "those who aren't responsible for removing radiators" that form over function is usually not a good thing. Then duck.

.andy

To email, substitute .nospam with .gl

[Christian McArdle]

I couldn't find a '3 dimensional' type valve. All the ones I saw were in one plane, so the hose spigot was always going to stick out.

Christian.

[Andy Hall]

Pegler Terrier 367 DLS series.....

.andy

To email, substitute .nospam with .gl

[Christian McArdle]

Cheers! (But I'm not redoing all my rads!)

Christian.

[Andy Hall]

You're not? I won't tell if you don't :-)

.andy

To email, substitute .nospam with .gl

[Mungo Henning]

Two points:

1) Before removing the radiator from the wall I have clipped a child's balloon over each pipe stub to catch any spills. This helps prevent the black sludge from hitting any carpeting or other floor covering. Make sure that you don't puncture the balloon as you slip the neck over the pipe stub though - perhaps temporary further inflation via the air pump might give some confidence in the integrity of the seal?

2) It's really useful to learn of other people's home-built tools and gadgets that they create for specific problems - thanks Set Square!

Mungo