DIY Home Compressor

We live in a rural area, which means among other things a well, a pump, and a pressure tank to get water flowing in our house.

Last week the pressure tank failed. The result was “short cycling” of the pump. As water was being used, the pump motor would go on about every 10 seconds, since there was no longer a reservoir of pre-pressurized water to be used from the pressure tank. Evidently this increased cycling would soon put an end to the pump starter, if not damaging the pump itself.

Money is tight, and I couldn’t see paying a plumber (though in retrospect I can see where they would have to charge what they would have if I hadn’t done it myself) for doing the job for me if I felt I could do it myself.

In my research I learned that a  band-aid for the blown diaphragm was to pump some air into the pressure tank, thereby created an air cushion, and at least a little reserved of pressurized water. This I did with my trusty DIY type home compressor, and the pump cycle time went up to about 45 seconds. Good, but not great.

So I bought the materials later on in the week  and yesterday replaced the pressure tank on our water system.

One major stumbling block for me was that this was a 20 gallon pressure tank, meaning that if it was full of water it would weigh about 240 lbs. I could move maybe half that, and half that again if I had to pick it up. How to lessen the weight was the issue?

The  tank is in the crawl space below our house, and the pressure tank drain tap outlet was too close to the floor to put a hose on it or a bucket under it. Even if I could, I’d still have to get the water up and out of the below grade space somehow.

Hmmmm?  Enter my trusty air compressor again.

With the power to the pump off so it would try to start and pump more water into the system, I closed the ball valve in the water line from the pump to the pressure tank, closed the ball valve on the water line to the rest of the house, and opened only the line leading to the hose bib outside the house. I placed the garden hose on the lawn away from the foundation, and started adding compressed air to the water tank.

By the way, if you don’t have lots of shut off valves in your home water system, it will always come back and bite you when you need to work on the water. If I do any work in any part of the house and there isn’t a ball valve in line to that area, I’ll always add one so that the next time I have to do something in that part of the house I can isolate just one area, and leave water running for other folks to use in other parts of the house… (bathrooms… you know?).

My compressor puts out 120 PSI or so, so I watched the gauge on the tank carefully, and when the pressure in the tank reached 20 PSI, I stopped adding air. When the pressure in the tank reached zero again, I added more air. It took a few fillings.

Sure enough, after about 5 minutes the compressed air in the pressure tank forced all of the water out of the tank, and further, blew out the line from the tank to the hose bib.This meant that when I cut the copper line to remove the old tank, very little water dripped out, and the copper pipe was completely empty for when I sweated the coupling in place after installing the new tank.

The rest of the job only took me a few hours, lots of swearing, and more than one bruised knuckle. However, without the compressor, emptying that broken pressure tank would have been a real roadblock to even starting the job.