Well pump cycles too much

[Pilot]

After just a little water flow pressure drops from 65 to about 40 then the pump comes on and in a few seconds pressure is back at 65. If flow continues, the cycle continues.
What's up?
How to check the problem?

 

[kelving884]

Your pressure tank. Google "checking water pressure tank". It easy to do.

 

[turnkey4099]

Your pressure tank. Google "checking water pressure tank". It easy to do.

Short version: Your pressue tank is water logged (lost most of its air bubble), drain tank and air up to 2psi below your cut-in pressure.

 

[redman135]

ditto turnkey4099. Been there, fixed that, straight forward fix.

 

[Rocky J]

Also if you do not correct the rapid cycling it will kill the pump motor. I went through this same problem two days ago, having a tire pressure gauge that was way off made it hard to correct the problem. I shut off my well and drained off the pressure, aired my blader tank up to what I thought was 28 pounds which would be two pounds under my 30 pound cut in pressure and it was worse then when I started , I started letting air out and it would get better so I stopped and went for a new air gauge, the new gauge read 43 pounds and after correcting it back to 28 pounds it was perfect. My tank and well was new two years ago after the last time it started hammering and I let it go, that ended up being a ruptured blader tank. Sense then I have to correct my pressure on the tank once a year.

 

[JD5210]

You have a leak some place. Turn off water between the pressure tank and the house to see if the leak is there. As already suggested check the pressure tank.

Check out this site: Guide to Water Tank Problem Diagnosis

If this does not fix the problem you have a leak in the line from the pump to the pressure tank or the check valve at the pump is bad. One way to check if it is between the pressure tank and the pump is to install a check valve in the house just before the pressure tank. NOTE if this stops the cycling it is just a temporary fix because while the line is leaking water it is taking on air, so when you turn on a faucet air and water will come shooting out, so be prepared. Are you seeing any wet spots in the yard? If not there is a good chance the check valve that is on top of the pump is bad.

This needs to be fixed to avoid burning the pump up.

 

[Valveman]

You have a tank problem. And if the pump comes on when no one is using water, you either have a leak or a bad check valve as well. If the pump only cycles WHILE you are using water, then there is no leak and the check valve is good, and only the tank is a problem.

The diaphragm in a tank bends back and forth every time the pump cycles. So called normal cycling every minute or two will break the diaphragm, just like bending a wire back and forth 100-300 times per day. Then the air gets out of the diaphragm and the pump starts cycling every few seconds instead of every minute or so, and the pump/motor is the next thing to go.

Air doesn't normally get out of a diaphragm tank on its own. Lots of cycling can expedite the loss of air as well as the loss of the diaphragm itself.

 

[bigdeano]

There are two kinds of tanks. The steel tanks have the water inside the plastic bag. The fiberglass tanks have the water outside the plastic bag. With the steel tank if the air pressure gets too low the water pressure in the bag will rupture the bag and you have your problem. With the fiberglass tank if the air pressure gets low the bag just collapses farther and it's not hurt. I replaced my defective steel tank with a fiberglass tank 16 years ago and haven't had any more problems.

 

[nikdfish]

If your tank is bad & you need to replace, go with the largest you can fit in the space if you can afford it. The larger the tank, the longer between pump cycles & the more steady your output pressure (also, the more water you are likely to have available during a power outage).

Nick

 

[turnkey4099]

As an added tip: The little pipe the pressure switch sits on is prone to plugging up if your well pumps any silt at all (Mine used to pump a lot of it). That results in the problem of the switch not reading the true pressure to the point that the pump will be slow to kick on when it should and equally slow to shudt off. Results in both over and under pressure conditions. I replaced my pressure switch wiring with enough slack that I can unsrew it without disconnectin wires.

 

[PatrickS2222]

If your tank is bad & you need to replace, go with the largest you can fit in the space if you can afford it. The larger the tank, the longer between pump cycles & the more steady your output pressure (also, the more water you are likely to have available during a power outage).

Nick

Almost certainly a tank problem - been there done that as well. First, switch off pump power, then release all water pressure. Leave one tap turned on is a good idea. Correct the air pressure in the storage tank as Turnkey described. Turn off tap, switch on pump and allow it to build up full pressure and then it will stop. Turn on a tap and check if an increased amount of water under pressure is delivered before pump restarts. Allow it to run for a minute or two whilst checking if any air is released. This may prove a split diaphram in the tank as Valveman described. Turnkey's mention of a plugged pressure switch or pipe is a possible but very unlikely fault for these symptoms.
Nikdfish's advice of a large tank being advantageous is spot-on as well. Starting up is what kills electric motors - especially under load, or against the inertia of heavy shafts or pulleys. They'll happily run 24/7 for ever ... or until their bearings wear out, but frequent starts will result in a very short working life.
A good friend gave me a huge pressure tank which was spotlessly clean, and cost him almost nothing (was in an auction lot of scrap metal) for our house water supply pump. Pump cycles between 45 & 65psi, but I can almost have a shower before it starts up! :laughing:

 

[Valveman]

You can get diaphragm or bladder (bag) tanks in either steel or fiberglass. Either fiberglass or steel a diaphragm is better than a bag tank. The diaphragm doesn't touch the sides of the tank as it moves up and down like a bag tank does.

But diaphragms and bladders are both susceptable to failure from flexing back and forth as the pump cycles on and off.

Even a large 80 gallon size pressure tank only holds about 22 gallons of water between 45 and 65 PSI. This is why the pump still has to come on when you take a shower. But with a large tank the pressure is decreasing from 65 to 45 for almost the entire shower. Only in the last couple of minuites after the pressure drops to 45 and the pump is started does the shower pressure increase back up to 65 PSI. With a smaller pressure tank this fluctuation in pressure from 65 to 45 may happen several times during a shower.

As was stated eariler, pumps like to run 24/7, starting is hard on a pump/motor, and starting against a load is even harder. So the fewer starts the better. The way to decrease the number of starts is to increase the run time of the pump. It is better for the pump to run for as long as you are in the shower, than it is for the pump to cycle on off even twice, much less multiple times. The longer the shower and the smaller the tank the more times the pump will cycle.

As for starting a pump against a load, it is just the opposite of what you may think. Starting at the low pressure of 45 PSI without any restriction is the bigest load and the hardest way for a pump to start.

Starting a pump against a closed or almost closed valve, as with a CSV, gives a mechanical soft start to the pump and decreases the starting load or amperage.

25+ years ago I would have also said the bigger the pressure tank the better. But those days are gone as there are much better ways of controlling a pump. There are several ways to get constant pressure to the house, and eliminate cycling while using a very small tank.

There are variable speed pumps and countless types of tankless controls, but I believe (and of course I am a little biased) the simple nature of a constant pressure valve is best.

 

[turnkey4099]

Something not mentioned (or I didnt' see it). If you have to correct the pre-charge in a tank, you will have to do it repeatedly. The air in thebubble is slowly absorbed by the water and eventually the pump will be short cycling again. Best to replace the tank...or the bladder if it is replaceable - some are. There are still a lot of old non-bag/bladder tanks out there. They have 'snifter valves' or other means of adding a bit of air every so often when the pump starts. Those valves also fail.

 

[Xfaxman]

I recommend adding a pressure gauge where it is easy to check.

Mine is on the input to the hot water heater: