I replaced my well pressure tank yesterday, and cannot eliminate a very rapid short-cycling on the cut-out end of the pump cycle. Sorry for the length, I didn't want to leave anything out...

Background:

The pump is a Water Ace RC10 Jet Pump (1 HP convertible 120/240, set to 240V, manual here, really dark picture here), installed in December '09 or January '10.

The pump is controlled by a Square D (or Schneider, or Pumptrol, depending on which branding you believe) pressure switch on the pump, not the tank T, and this is brand new today. It came spec'd at 30 PSI cut-in, 50 PSI cut-out.

I do not know the age of the well itself; though the home was built in 1970's. I also don't know the depth of the well, or its diameter. 1-inch hard, black, plastic tubing comes in through the crawl space wall and runs to the jet pump.

Until yesterday, our pressure tank was a rusty, 75-gallon monster, which you can (hopefully) see behind the new, pretty blue tank in the pictures. The new tank is a 20 gallon bladder tank ("H2OW-TO Pressurized Well System Tank"). We never had any instances of short cycling with the old tank, but we had low pressure with two faucets open, or one faucet and the washing machine, which prompted the replacement.



Here's a short history of the problem:

I installed the new tank, and tank tee, yesterday morning. Hopefully the new pictures help out a little here; the tank sits up on one set of cinder blocks so that the system-side piping meets the water system at a verticle "L" turn. There are a pressure gauge, a spicket and an over-pressure valve on the tank-T. On the pump side of the T, there is a 1-inch check valve, which is (triple and quadruple checked,) pointed in the direction of the flow of water from the pump to the tank-T.



Air in the bladder: I've tried to keep this set at 2 PSI below the cut in of the well pump, which I've had at 30/50, 40/60, and 20/40. I even tried going as low as 15/30 just to see if maybe the pump couldn't keep the pressure that high, but none of the changes eliminated the rapid click-click-click cycling at the cut-out pressure. Each time, I made sure to empty the entire tank (and the entire water system) before adjusting the bladder pressure, I open a faucet at the opposite end of the house, flip the breaker to turn the well pump on, close the faucet at the other end of the house once air stops coming out, and watch the pressure gauge climb to the cutoff pressure; the needle on the pressure gauge shudders back and forth 5-10 PSI the entire way up, and then the pressure control switch click-click-clicks for 10+ seconds at the cutoff pressure, eventually stopping. The needle rests at the cutoff pressure and does not shudder or drop. It doesn't appear to lose pressure at that point until I open a faucet or start draining the tank.

After all that messing around, I decided it must be something else, so unplumbed the check-valve and cleaned it out, unscrewed and cleaned out an in-line filter casing (further down the system, which interestingly had no filter in it), and shut off the water to the washing machine (I had read that a clogged washing machine filter could cause short cycling). None of these seemed to abate the short cycling.

Next I replaced the old pressure-controller with the new, Square D one. In the process, my girlfriend (I would never do such a thing) managed to tear the small tubing connecting the well pump to the pressure switch, so we re-plumbed that with flexible copper tubing. The new switch and tubing didn't make a difference.

I'm really kind of at a loss at this point. The guy at the hardware store seems to think either the well pump can't hold pressure at 30 PSI or that the well doesn't have water, neither of which seem to make sense to me, since if I set the pressure switch to 50 PSI, it climbs past 40 fine, and gets short cycles on 50, and I've been pumping water out of the well all weekend and haven't noticed any slowdown in the fill-up times.

Any thoughts and ideas are welcome.

EDIT: It looks like my embedded flickr images aren't working. In addition to the links above, there are some wider shots on my flickr stream.

 

perhaps you can have some one stand ready at the fuse panel and as soon as your well pumps to the shut off pressure, have the breaker thrown so the pump can not on-off cycle. then listen closely or watch your pressure gauge and see if the pressure drops. perhaps yoru check valve is letting water out or the line to the pressure switch is letting water back. it almost sounds like water is backing up back into the well?

 

@billy_boy: I crawled down there to try this a few times- I just yanked the plug to the pump myself with my ear to the check valve; if any water is rushing back through, it's too fast or too little for me to notice. Interesting thing though; the first time I unplugged it and heard nothing, I plugged it back in, and it didn't short cycle. It just clicked on, pumped for a second, and clicked off at the cutoff PSI (which right now is 40 PSI).

The second time, I unplugged it, listened, heard nothing, plugged it back in, and it went right back to short cycling like before. Bummer.

 

For the pump to do this at cut off, there has to be a restriction in between the pump and tank.
Do you have a check valve or shut-off valve in between the tank and pump?

The should be only one check valve in line and it should be the foot valve in the well.

From looking at the pics, it looks like there is maybe a check valve in line.
Take the check valve out, and it should be fine.


Travis

 

@Travis:

There is a check-valve in between the tank and pump. If it's true that it isn't supposed to be there, then that's almost certainly my problem. I'll take it out first thing tomorrow and report back.

 

This absolutely was the problem. So much for 1) The hardware store guy who told me I needed a check valve between the pump and tank; 2) The hardware store "plumbing expert" who told me I had to drill a new well; 3) the instructions on my well pump that said I needed a check valve between the pump and tank for bladder tanks.

High five to 1) The instructions for the bladder tank, which didn't mention a check valve; and 2) Travis. You rock, man.