My pump kicks in every 3 seconds or so while at moderate tap flow. You can see the water pressure degrade and increase. If you open the tap all the way, or open multiple taps, it stops pumping, as if the pump overheats and then resets. I have a pressurized bladder type tank that is installed about 2 feet ahead of the pressure switch. I understand that a bad pressure tank can cause this problem. But read on, it gets better.
Earlier this week, I had a good size pin hole leak in one of the pipes, as evidenced by frequent cycling of the pump when everything was cut off. You could hear a funny noise at the water heater when the pump cycled. This noise has been around for about a year and a half. It has not always done it.
Anyways, I had this good size leak under the house and the noise disappears. You can run a tap or taps wide open and no surges in pressure, a steady even flow. Everything seems to be working normal. Tonight, I cut power to the pump and cut out a section of pipe and repair leak. Restore power and noise comes back.
It seems that air in the system has something to do with it. I can almost go as far as to believe an air bubble right at the "T" going to the pressure tank is causing it. The tank is the lowest device under the house, followed by the pressure switch being about 6" higher than the port on the tank. The tank is mounted horizontally, with the air inlet lower than the water inlet by about 2 inches. The way its plumbed, theres nothing existing to bleed air out of the system at either the pressure tank or switch.
I never gave this problem much thought until finding TBN and this great sister site last year. I read posts posts and did searches and I began thinking that when this problem is occuring, its like the pressure tank is not even there. Any ideas of the cause or the cure?
The precharge pressure in the tank should be set at 2 psig below the pump cut in pressure. This should be set before the tank is installed in the system.
Cut the power off to your pump and open the drain valve nearest to the tank or closest fixture to the tank. When the water stops, close the fixture or drain valve. You may see the pressure on the pressure gauge rise slightly. This is normal.
Open the drain valve or fixture again to remove all of the remaining water from the tank. You may need to open and close the drain valve or fixture repeatedly, to get all the water out of the tank. Once all the water is out of the tank, you can then check the precharge correctly. Adjust the pressure in the tank to equal 2 psig below the pump cut in pressure.
The tank simply stores water between the operating pressure range controlled by the pressure switch. This stored water in the tank keeps the pump from turning on and off too frequently.
Since you say you have a bladder type storage tank this is what I would do:
Turn the power off to the pump. Open the faucet and let the cold water run until there is no pressure left and it is just dripping out. Open the hot water side also, to make sure you dont have any pressure trapped, and leave it open also, just dripping there.
Get a tire gauge and go over to the storage tank. There should be a valve on it just like a car tire, take the cap off and check the pressure. If it reads 0, or is less than your cut in pressure (usually around 30 PSI) you have a problem. It should be right around that value (some have 40 cut in and 60 cut out). If it is 0 as I suspect/ put 30 PSI of air in it, and go read the paper. Come back in an hour and see if it still has 30 PSI. If not then you know the bladder is ripped, has a hole in it, or the valve core is loose or just needs air and you will have to replace the tank if it needs a new bladder, as these are usually non servicable (welded shut). If it still has 30 PSI in it, maybe it just needed air. Let me know what you find.....
Thanks for the replies. I went under the house and pushed in the inflator valve and sure enuff, water came out. Luckily, I had another tank on hand, gleaned from a house slated for demolition. I had to take out the framing from around the crawlspace opening and dig a pit as the replacement is about twice the size of the original. New one works like a champ!
Boy that is disappointing to see the water coming out of the valve [img]/forums/images/icons/mad.gif[/img] Sound like there was alot of digging involved upder the house. Boy I hated when I had to do that under a mobile home that I was working on, it seemed to take forever to get the digging done [img]/forums/images/icons/shocked.gif[/img] Glad to hear that it worked out in the end....
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