Was putting radiator back on wall, attached pipes, turned spindle t
open valve back up and it snapped. Can't open the valve now. Gutted. It's the right-hand lockshield valve on the bathroom radiator (bot vavles are lockshield valves). Part of a Combi system. Do I now hav to drain the system before replacing the valve
-- The Count
If it's a sealed system, then you would at least need to release the pressure, but realistically, you would also need to partially drain the system to below the level of the valves as well.
If you can find another identical valve (apart from not being broken!) and de-pressurise the system, you *may* be able to change it without draining down - especially if the bathroom has a hard, wipeable, floor covering.
Put lots of old towels down to catch any spillage. Get the new valve ready to fit - valve closed, and compression nut and olive removed. Keep the old valve pressed down onto the olive, and unscrew the compression fitting nut. Then whip the old valve off, and the new one on, and screw the (old) compression nut onto the new valve. There will be *some* spillage, but the open (unpressurised) pipe will only be exposed for a fraction of a second - so you shouldn't spill much.
An assistant with a wet vacuum would reduce that spilage to almost zero. Why all plumbers don't carry a wet/dry vac is beyond me.
Dave
|Set Square wrote: | |> There |> will be *some* spillage, but the open (unpressurised) pipe will only |> be exposed for a fraction of a second - so you shouldn't spill much. | |An assistant with a wet vacuum would reduce that spilage to almost zero.= =20 |Why all plumbers don't carry a wet/dry vac is beyond me.
Evolution is taking a long time developing four hands?
--=20 Dave Fawthrop
17,000 free e-books at Project Gutenberg!
Much appreciated. I'll try to find an identical valve. When you sa de-pressurise the system, does that just mean turning the boiler off
-- The Count
You certainly need to do that and also make sure that the pump is off, so turn off gas and electricity.
We have both assumed that you have a sealed and pressurised CH system because that is typical with combi boilers.
This means that you do not have a small header tank in the loft and that somewhere - typically near the boiler - there is a filling loop. This is a valve with threaded fitting and a non-return valve with another valve connected to the cold mains. Between them goes a short braided hose (which should be removed when not in use). On the boiler, or somewhere on the system, there should be a pressure gauge. You may also have separately, although typically it's inside the boiler, a pressure vessel. This is a metal container with a diaphragm with air or nitrogen behind it. When the system is filled, this is compressed and maintains a pressure in the system as well as handling the expansion of the water when heated.
If you have this, then dropping the pressure consists of hooking up a hose or a container to a drain c*ck at a low point on the system. When you open this, the pressure will release and push the water out. You can then open a vent on the radiator in question and let the water naturally flow out through the drain. With a container under the union of the broken valve, you can open the union nut and check when water stops coming out. At that point, you can close the drain c*ck.
If you have an open vented system, the procedure is to tie up the float or otherwise turn off the water. Then proceed with the drain c*ck as before.
Note that it is likely, if no corrosion inhibitor was used, that the water will be discoloured yellow or black. This stains furnishings indellibly so lots of protection and ability to mop up are called for.
If the water is black or there are signs of sludge, then it would be a good opportunity to flush the system thoroughly by draining all the way down and refilling a couple of times. If you have the sealed system, refilling is simply a case of closing the drain and hooking up the filling loop. Pressurise up to about 1.5bar on the gauge. Once the water is reasonably clean (if it has been black), you can add a flushing agent to the system and run it hot for a week, then flush again.
Finally, add a corrosion inhibitor. You can use liquid ones with sealed systems but it can be a fiddle. While you are plumbing, you could put in an upward pointing short length of pipe in a convenient place and then fit a stop end or a valve to it. Liquid chemicals can be added with a funnel or by siphoning with a tube.
Alternatively, there are gel inhibitors and flushing agents that can be injected using a mastic gun. The cartridge comes with a short tube and a nozzle which goes into a radiator vent. They work well if you ignore the manufacturer's procedure of trying to inject with the system under pressure. Leaking or pissing out is likely from the nozzle. Injecting into a radiator while the system is empty and not pressurised is much easier and cleaner.
No - but it goes without saying that you don't run the boiler while you do this! De-pressurising means letting some water out so that the pressure gauge reads zero. You could do this by opening the valve which *does* work on your bathroom rad, while the rad is off - and collecting a litre or two of water in a container.
You will, of course, need to re-pressurise it via the filling loop when it is all back together.
[If this doesn't make sense, maybe you shouldn't be doing any of it!]Thanks Set Square. That does make sense. I'm fine with re-filling, bu
wasn't too familiar with draining. But your method sounds good. Th reason I put about 'just' turning boiler off, is when I do the pressur seems to be at zero (since removing bathroom rad and it' contents)....but I suppose it must not be quite at zero, and 0.1 ba may cause problems?
Cheer
-- The Count
You don't want *any* pressure in the system when you swap valves - otherwise you're likely to end up with a flood.
Under normal circumstances, the system should be at about 1 bar when cold (with the boiler not running) and about 2 bar when hot.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.