*Changing Out A Pressure Tank*
By: Jaden
28 Spetember 2005

We noticed our water pump was running excessively. Itíd run 5-6 times per toilet flush and run 20+ times per load of laundry. This is a quick way to burn up the pump + it sucks up a lot of electricity starting so much. When taking a shower the pump would start about every 30 seconds and run for about 20 seconds. Every time this happened the water got cold. That just wouldnít do. I shut the pump off and drained the system and then used a tire pressure gauge to check the air pressure in the tank. Nothing, bone dry. I inflated it to 30PSI with an air compressor and then charged up the system again. It worked ok for about a week. Then the same thing happened. Checked the air pressure againÖ..empty. OK, time for a new tank. Well there goes another big chunk of change.

I had already talked to a plumber I know about pressure tanks cuz I anticipated this happening. He told me not to get anything under a 30- gallon (capacity) tank. You want the most capacity. Tanks are advertised on their boxes as "50 gallons" or whatever, but thatís BS. Read the fine print. That doesnít mean you can put 50 gallons of water in the tank, itís just a comparison figure to a "standard tank". Ignore the big #ís and pay attention to the fine print. Buy the tank by itís CAPACITY size and try to find a big draw down, nothing else. The higher the draw down #, the more water is drawn from the tank before the pump starts.

Nerisa and I happened to be near Home Depot and checked out their tanks. They wanted $199 for a 35 -gallon capacity tank. We decided to note it and then check around to see if we could find a better deal. The next morning we hit the local hardware store. I knew there was a tank sitting in the back and itíd been there years. Took a look at it and the price was $239.00. Couldnít find the info we needed stamped on it so I went and found one of the owners. He brought the book down and we looked it up by part #. It was a 32-gallon capacity with an 11.9 draw down. Well, we couldnít afford to dish out $240 bux so Tom said "Let me go see what I can do." He did some figuring and gave it to us for $179 so with the governmentís cut we walked out with a new tank for $188. Itís only 3 gallons less than the home depot one and we saved 20 bux or so. Most people if they need a tank replaced will call a plumber who will bring one with them. It pays to know these things and it pays to be friendly with the local hardware store owner.

So enter the new tank. I used my tire gauge and checked the air pressureÖright on the money. 1-3 PSI below the pump turn on (cut in) pressure.


I shut the pump off and drained the old tank and then shut off the main valve. This way any residual water in the higher pipes wouldnít flood me.


Then I simply uncoupled the union, disconnected and removed the wires and then disconnected the supply line.

The old piping would be reused so I unscrewed it from the old tank which then got heaved out the door. I cleaned up the male threads and wrapped Teflon tape around them and screwed the pipe into the new tank.



The new tank was 2 times higher than the old tank and it didnít fit in the exact same place. No big deal. I just had to solder in a couple of 45 degree corners and relocate the union and it went together fine. I rewired the switch and hooked up the supply line.


A rather simple modification

Hereís a couple of comparison pictures to show the massive difference in tank size.


To charge up the tank open the main valve and turn on a faucet or two. This will allow air in the lines to escape. After a couple of minutes shut the faucets. Youíll hear creaking inside the tank, itís ok. Itís just the rubber bladder stretching. Ours made noise for a couple days and now it doesnít.

With this new tank the shower stays HOT when the pump turns on which is every few minutes instead of seconds. A toilet flush only uses 9 PSI instead of running the pump 6 times, the washing machine only starts the pump 1-2 times depending on the pressure when the machine starts. It was well worth the $188 and definitely better than replacing a $700 pump.

Swapping out this tank is a relatively easy process. It took me about 1 hour.

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