Dual pressure tanks

Oops

I didn't want to take the chance on hitting the connection T while I got the tank up there where it's going to sit so I left it off. When I got the tank where it goes, I tried to thread the T into the plastic threaded flange and got it cross threaded. It might have held that time but I pulled the T out to look at the threads then put it back in and it felt worse the second time. It felt even worse the third time... by then I knew there was no way it was going to seal. At least not dependably. Plastic threads? Really? 1 1/4" NPT too, not small stuff.

Turns out the box store carries FloTec products but nobody in the State stocks replacement parts for them. You would think that plastic piece has been stripped before and somebody would stock a few of them but they don't.

Parts and Pieces

parts T's and backflow

oops backflow preventer

gauge tank air pressure

bend bending pipe

Well first, of course, is the tanks. There are two FloTec FP7125 Pre-Charged Pressure Tanks (Vertical) - 120 Gallons each, hooked in series.
Like I mentioned earlier, I'm not sure what possesed me to install two. I saw an install using three and originally intended to do that.

The whole theory is that the more drawdown you have available the more you can do with stored energy before the pump has to come on and pressure up the house again. These tanks, rated at 120gal each, are actually only 50gal tanks and will have 15 1/2 gallons drawdown each with the 30psi/50psi pressure switch I'm using. That is assuming I can get the air pressure set right on the tanks. The one tank is still pre-charged at 40psi and will need bled off to 28psi (2psi below the bottom setting on the pressure switch) but the other tank has no pressure in it now since I stripped out the flange and had to pull it off.

The T's both are 1" NPT and need a 1x1 1/4" reducer to fit the tanks. That reducer ended up being galvenize because I couldn't find any brass or poly that size. There is a drain valve and pressure guage on each one. One gets a pressure relief valve in case the pressure switch messes up and the pump just keeps on running. You can also see the 6" nippel that will supply system pressure to the pressure switch itself.

On my first shopping trip I brought back a 1" backflow preventer. This is to keep water on both sides of the pump so, if for some reason the pump can't hold the water column above it, you don't get hammering when when the pump comes on. When I looked at the 1" one, I decided it looked pretty restrictive and research on the web kind of talked me out of installing one at all. I got to thinking though, since we do get a bit of hammering sometimes, it's possible that we don't have a backflow preventer in the well. There is no way to tell what's in the well without pulling the pump and that is preferably a summer time project. I decided to go ahead and put in the biggest one I could find, 1 1/2", and if I later decide it's causing more trouble than it's fixing, I'll just yank it out.

I was thinking it was going to be difficult to get both tanks set equally to 28psi and decided I needed to connect the two so they shared the same air pressure. A nifty little manifold and a gauge and I ended up with a pretty slick setup that lets you see the air pressure and add air without climbing up in where the tanks sit.
They are at 28psi empty right now ... I'm waiting for the tanks to get filled with water the first time to see what the pressure will be when they're full.

Installation

tank number 1

old and new

new tanks tanks are in

installed waiting for water

demo demo

leak leak

leak fixing the leak

The install was easy enough once I got all the parts I needed. It took a while to make sure the power was off since none of our breakers are marked right but I got the right one by trial and error and a test meter.

When I hit the breaker for the first smoke test nothing happened. I had to study the pressure switch a bit before I figured out that you have to hold a lever down until there is enough pressure to stop the low pressure cutoff from killing the power to the pump.

When I finally got the pump going and started building pressure, the T on tank #2 sprayed water! It was tight too... I killed the power, closed all the valves feeding the tank and ran the faucet in the kitchen. That drained the tank completely, there was only a quart or so of water left sitting in the lines. I took the T clear off, cleaned it up and put new pipe dope on it. I put it all back together, hit the power and it leaked again!

When I got back from SBS with the new T, 1 1/4" to 1" reducer and some new pipe dope, I put it all back together and let it sit for an hour just to give the pipe dope time to cure. This time it didn't leak when I turned on the pump.

All done