How To Blow Air Through Water Pipes

Draining a hot h2o tank and plumbing with compressed air

Summer is over, so it'south time to shut the cottages and go them ready for winter. This includes thoroughly draining the plumbing and then that freezing water will non cause pipes to crack. In recent years, that's e'er been my job. The plumbing was designed to drain past gravity alone, simply you lot can't always count on that to clear everything, and there'd be a few leaks to set the next year. So I came upward with a method of using compressed air to drain them, fast.

I start in each of the 9 buildings by endmost the main close-off valve. This isolates the plumbing in the cottage.

I also make sure the hot h2o tank is turned off!

I apply a cheap pancake manner air compressor. It'southward built amazingly cheaply, and information technology's very loud and non very efficient. But it's calorie-free, then easy to take from one cottage to the next.

The first lodge of business is to make sure the hot h2o tank is empty. It volition drain with gravity, but it takes a long time, so compressed air is very handy for force-flushing it. I open up a cold h2o tap, then inject air in the hot water side of the system through some other sink, typically a bathroom sink.

I fabricated a fitting that clamps to the sink for injecting air, though, in a compression, i could only agree the nozzle confronting the sink and cup the fingers around it. You lot wouldn't get a very skilful seal, just information technology would be plenty to button the water out of the hot water tank.

Forcing compressed air in the hot side will push the water out of the hot water tank dorsum out the cold side. Having nowhere else to go, it comes out the tap.

Very of import: Make sure your hot h2o tank is turned off! An electric hot water tank will fire out its heating elements if information technology turns on with no water within.

The reason this works is that cold water is always fed into the lesser of a hot water tank. Even if the common cold water connection is at the meridian, there is a pipe within the tank to release the common cold water at the bottom. Pushing air into the tank from the top (through the hot h2o side of the plumbing) volition button the water out the cold water side.

Once the hot water tank empties out, air and water start sputtering violently out of the faucet.

In one case it'southward mostly air that's coming out, I close the faucet and pump some more than air in the hot h2o tank. I don't know what pressure I typically end up getting in the tank, simply I'd say it's probably around 15 psi, or one bar.

Then information technology's time to open the taps, one at a time to blow out whatsoever h2o that is even so in the pipes.

Final comes the toilet. Flushing it causes the float valve to drib, which in turn opens up the valve. With all the air shooting out into the partially emptied tank, this can cause quite a flake of splatter.

I so typically jam the float back up with a toilet brush and practise one more than round, pumping up the hot water tank and letting air out of each faucet and tap.

Last I open the main tap of the cottage to let the air push whatsoever h2o might still be in the supply line out.

But I did this cottage before the remainder of the army camp was drained, then I disconnected the principal supply hose and let it blast the remaining air out the hose. I didn't desire to leave it hooked up, because the main shutoff valves typically leak a bit, and I didn't desire to risk leakage pushing water back into the plumbing.

Next information technology's time to empty the drain traps as much as possible. I use a toilet plunger with a hose in it to push air in the trap.

This pushes the water beneath the plunger out the bleed. I then lift the plunger briefly, lower information technology again, and repeat until the bowl is more often than not empty.

What I realized since though is, with the compressor at 100 psi, by just aiming the nozzle into the drain and letting it blow, the Venturi result is plenty to button the h2o back also, elimination the toilet basin even faster.

I besides use the plunger on the sink and shower drains.

I can't go all the h2o out of the drains this style, so antifreeze still needs to be added, merely getting equally much h2o every bit possible out certainly helps.

Afterwards that, information technology'due south on to the adjacent building, and the next. With nine buildings with indoor plumbing at the camp, I don't desire to accept too much time in each ane!

Coincidentally, the cottage I was draining in this article is #7, the structure of which is described here. And the nearest 1 in the picture at left is the one whose deck railing I repaired in 2013.