I need to replace the gate valve feeding from our cold water tank to the hot water cylinder. The cold water tank is very inaccessible in the loft (close to roof and in an awkward place to get at).
So I either need to drain the cold water tank (two tanks actually, so lots of water) or I need to block the feed pipe temporarily by some other means.
Do I have any chance at all of freezing it with freezer cans?
Any other ideas?
Can you reach into the tank to stick a bung[1] into the end of the pipe?
[1] Posh rubber pointy thing designed for the job, or large cork, or a carrot!Those freezer packs do work, but they cost mega pennies. Depends on the depth of pocket I fear. Brian
Or just this once, make the effort and fit a tap where its not hard to get at for the next time you need to turn it off. I've nver quite understood why they stick them just under the tank in the most impossible positions. I suspect a lot of them were put in before the roof!
Brian
Had to do mine just recently. I turned off the tank feed, and waited until it ran out with normal use. There are 3 outlet pipes from my tank, every one with a gate valve, and not one of them still working. Swapped them all for full bore isolating valves. Just need to remember to operate them periodically.
I've also had to drain down the heating twice, to replace the two gate valves either side of the pump which are there so you can change the pump without draining down the heating. The pump has never needed changing...
I had a new radiator fitted about 18 months ago. The alleged plumber froze the pipes instead of draining down. It all went wrong and turned into a huge f*ck up. Drain the tank.
Can you turn off its input? If so then drain it.
Not much, they don't take away much heat per can.
You can freeze pipes using crushed ice and salt. When you add salt to ice it lowers its freezing point causing it to melt, it does this by extracting heat from its surroundings. If its a pipe full of water it will freeze. However without experimenting I couldn't tell you how much crushed ice it will take or how long so I will let you do that.
You also need to find someway to keep it around the pipe, maybe a plastic bag or two. If you decide to have a play then wear gloves or you may get frostbite, it gets very cold.
Is it still possible to buy dry ice from the water board? Potentially much cheaper and a greater capacity for a planned job like this. On a
15mm pipe, a can of freezer will give say 10 mins worth of freeze, whereas a big pile of solid CO2 can keep a pipe frozen for much longer.
Yes, we could go this way I suppose, it's a lot of water though as there are two interconnected tanks in the loft. As long as I can turn off the tank feed separately from the mains water incomer so we still have water in the kitchen it should be possible I guess.
:-)
You should be able to fit an isolator tap in the feed to the tanks if there isn't one already. Provided you can turn the water off at the mains, and run the kitchen tap until it stops, there shouldn't be much spillage from cutting into the supply pipe.
Alternatively, can you access the tanks enough to be able to tie off the ball valves?
Ummm....
1 - Calculate the flow out of a 28mm pipe over N seconds. 2 - Freeze pipe or not 3 - Apply circular pipe cutter & circular pipe deburrer 4 - Quickly fit an OPEN push-fit lever ball valve 5 - Turn push-fit ball valve OFFInterspersed between 3 and 4 will be a period of time...
The period of time may be short, punctuated solely by some light splashing. The period of time may be long, punctuated by screams, sobbing, underwear filling and Mr James Cameron coming around to do some test shoots for Titanic-II & The-Abyss-II. If he arrives in a yellow submarine shaped thing, just consider what the wife is going to put you in.
You could make a wood frame for the area, lining with 500mil plastic sheet securely fixed, with tank connector fitted to a low point to
15mm hose pushed over a stub of copper down the stairs. Water will spray even from a gravity feed so all but the front will have to be higher than the pipe being cut. Trap the plastic between the frame & wall (drill, plug, screw).Goggles, breathing apparatus and dry suit are optional. Waterproof phone to the plumber may be useful, but their response time may be delayed by raucous laughter at the other end. Telephoning a vet may be quicker and more fruitful, if only to remove the objects the wife is going to shove into every orifice should the idea not work. For onset of hypothermia, a perhaps more tolerable way to die consider having a spare AA emergency foil blanket. This at least gives her something to apply duct tape to before clubbing you with the monster in law (or clubbing you aided by the monster in law should she prove too heavy to wield).
Not sure if they do 28mm push fit lever ball valves tho...
"Wait a bit"?! Several hundred gallons of wasted water and lots of heating down the drain. Anyway I don't need to turn on the *hot* taps to drain the tank. It'll take a long time though.
Just turn off the supply to the tanks and wait for them to empty naturally then.
Tim
Just turn off the supply to the tanks and wait for them to empty naturally then.
Tim
What's the problem with the gate valve?
If it functions enough to reduce the flow (if not shut it off completely), that might enable you to cut the pipe 'downstream' of it and fit a new valve. Then leave the old one open.
If not, then it depends on how much flow you get from the 28mm; is there any possibility of catching any water in a bucket during the few seconds it would hopefully take to remove the old valve, and quickly put a new (closed) valve in it's place?
(I recently changed a leaking service valve on a 15mm CH pipe without draining down, using exactly that method. But the pressure was quite low.)
In general or his specifically?
In general when they work, and are a few year old, they tend to let by. When they fail the gate tends to snap off the spindle meaning they either never close, or close and then never open etc.
If close to the tank, it might be possible since the pressure will be low. However the risks should something going pair shaped and you end up dropping a gallon of water in a loft could have far reaching consequences ;-)
Yup, not too difficult if you have everything ready to swap and do the thumb over the end of the pipe dance quickly.
What's the cost of the water and gas (electricity?) that heated it compared with the cost of the freezing kit and the consequences of it going very wrong...?
Wouldn't have worked for me. The stub of pipe after the olive was too long to go into the replacement valve. I had to saw off about 1/4" from all the pipe ends.
On a totally different occasion (doing some plumbing in a second floor flat), I cut through a pipe which I thought would be empty, and water came gushing out. Quickly clamped my hand over the end to stem the flow/flood, which it did, but the pipe end was razor sharp, and cut a 15mm disc in my hand, with blood going all over the place...
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