Turn off hot water without hot water valve

Question

I have a leaky pipe on the hot water side that I'd like to fix. Following the pipes back to the water heater, I don't think there's a shutoff valve installed anywhere in the line, not even at the water heater outlet. At least, not one that is obvious for me to identify. How inconvenient!

I definitely have a shutoff valve on the cold supply inlet. What is the correct way to "turn off" the hot water so I'm not swimming when I disconnect the leaky pipe? The water heater is in the basement and the pipes in question are a few feet higher than the water heater.

Answer 1

My approach would be to turn off the water heater and the cold supply.

Then open a hot tap below, or as close to the area of the leak, to drain the hot pipe.

Then be prepared to catch the remaining water when you cut the pipe around the leak.

Supplement: One can get “ice clamps” that can be used to isolate either side of the leak but can be fun if the water pressure pushes the ice plug out...

Answer 2

Another simple and easy approach might be a repair clamp, search term " repair clamps for pipe leaks". Must meet the correct requirements like temperature, pipe type, drinking water compatibility.

A drainage could be avoided, and thus the danger of destroying old valves by closing and opening them the first time after decades.

If it is an old standard valve that is already leaky, the stem (compression) sealing package could be the cause. A simple tightening of the pressure nut may help.

The thermal insulation (re-) applied afterwards should have the same thickness all over the pipe - that way this clamp location could be easily identified.

And the cause for the leak should be identified. With metal pipes, the rule is from less noble to more noble in flow direction. F.e. the sequence copper - steel - copper could produce corrosion pits. Copper can only be used if the water meets the requirements for copper (ion types and quantity, acidity).

Answer 3

I had this with a previous house. I've also had a house where in spite of having a hot water shut-off, the valve was leaky and was mainly only useful for damage limitation. The solution is pretty simple - turn off the cold water inlet and drain down the entire system, hot and cold.

This will be time-consuming with the heater in the basement, of course. Drain the pipes at ground level first, as best you can. Start by opening all taps/faucets. After that, if there is a suitable drain valve and hose connector then use that to drain down the remainder of the contents of above-ground pipes. Finally you'll have to drain the pipes in the basement into buckets. If you have a suitable pump then you may be able to just drain into a bucket and have it pumped out for you. (Since this is likely to happen again in future, I suggest investing in a pump would be a very good idea.) If not, you'll just have to get several buckets and bucket-brigade the water out of the basement.

If you can guarantee to have the fix completed quickly, then a pipe freezing kit (such as this one for example) can shut off water in a pipe temporarily by creating a frozen "plug". These kits are great for professionals who can get the job done rapidly and have all the right tools and parts to hand. As a DIYer though, you can usually expect jobs to take longer than you expected. I would 100% recommend not using a pipe freezer for any repairs you'll be doing, because there is an extremely high risk of the pipe unfreezing while you're working and filling your basement with a couple of inches of water! Do it the safe way instead, and drain the system down. It's much better to regret a bit of time and some aching muscles than to regret Katrina-style flood damage.