Well, well, well...

Timco

Howdy.

We bought a home that has 2 wells. I’ve never worked with wells before. Our irrigation is set up so a well re-feeds a 1000 gallon tank and I use another centrifugal well pump (1hp 10gpm) to move water from the tank through some filters and to the sprinkler mains. The issue is the pump in the tank cycles off the pressure switch every 3 seconds on and 3 seconds off. The pump is rated for 300 cycles a day and one zone exceeds this. Can I throttle a pump like that back so it maintains 60psi on the biggest zone then cycles much longer on smaller zones? Not a cheap pump. Thanks.




Tim

hot_rod

yeah, try adjusting the pump speed to the glom you need. or a larger, additional well-trol tanks

Ironman

You should be cycling the pump from a water level sensor in the tank, not a pressure switch.

egansen

I'm just a home owner but I have lived with wells for water supply for along time. If that little WellXtrol tank is on the second pump that feeds the irrigation system i suspect that it is may be too small. I have a 3/4 horse 10 gpm pump in my well and it has a 44 gallon pressure tank on the system. The tank is usually sized to the pump and it allows the pump to run longer but with fewer cycles (like a buffer tank on a hot water heating system). Another possibility is that the bladder in the tank has failed and the tank is water logged causing short cycling of the pump.

The pump you have is ment for deep well (high head) applications. On some of the old farmsteads I have been around that have their water supply set up like yours (with a storage tank) the second pump is usually a shallow well jet type pump that draws water from near the bottom of the tank.

What you have going on is like an oversized boiler with too many small zones causing short cycling.

Timco

hot_rod said:

yeah, try adjusting the pump speed to the glom you need. or a larger, additional well-trol tanks

I’ll add a tank today. Can add a second. There’s only one pump speed pretty sure. I was considering a BV to choke it back a few GPM.

Timco

Ironman said:

You should be cycling the pump from a water level sensor in the tank, not a pressure switch.

I need to maintain pressure to the sprinkler mains. The pictures pump does that. Then there’s a well pump that recharged the tank based off a special program on the sprinkler timer.

EBEBRATT-Ed

Well expansion tank is likely bad. The bigger the better to prevent short cycling

Jamie Hall

Both the well and your sprinkler pump need to have properly sized expansion tanks. Unless the well pump is tiny, that tank in the picture isn't big enough.

Go here: https://www.amtrol.com/resources-rewards/selection-tools/
to size both tanks.

Don't throttle the sprinkler pump -- it won't like it and you'll waste a lot of electricity. Set the pressure switch for the sprinkler pump to give the pressure at the sprinklers which you need.

You should also have a float valve to control the water level in that storage tank.

Timco

Jamie Hall said:

Both the well and your sprinkler pump need to have properly sized expansion tanks. Unless the well pump is tiny, that tank in the picture isn't big enough.

Go here: https://www.amtrol.com/resources-rewards/selection-tools/
to size both tanks.

Don't throttle the sprinkler pump -- it won't like it and you'll waste a lot of electricity. Set the pressure switch for the sprinkler pump to give the pressure at the sprinklers which you need.

You should also have a float valve to control the water level in that storage tank.

The well pump just runs timed from the timer to fill and is wide open. It rests for an hour between cycles to cool and recharge well after 2 hours. The new sprinkler pump I dropped in the tank is now moving more GPM than the last one and the tank does not refill fast enough for the sprinkler pump. With 6 minutes left on the last zone it sucked air. It worked well before I was told. That was starting with a full tank. Half zones one day and half the next. I’ll buy a 1/2 HP well pump for the tank and reduce that pump’s size to get less GPM and I’ll add a big well tank. Set well tank to 40psi since that’s the low side of the pump switch and well tank can charge up to 60 with the system.

Jamie Hall

Just be sure the pump -- either one -- never runs dry. They really don't like that.

hot_rod

You've already throttled that submersible sprink pump by reducing it two sizes on the discharge Looks like an 1-1/4 discharge reduced to 3/4" ID hose?

If it is grossly oversized for the gpm required, add more sprinklers or larger gpm head Best to buy the correct size pump, as Jamie suggested. Or add a variable speed control.

Either fill the tank faster, or reduce the drawdown flow rate if you are trying to match them better.

Intplm.

You definitely need to add a a pressure tank.
I suggest installing the largest one you can afford and that will fit where you want to install it. Installing or adding a tank (s) to what you have now will be a big help.
This, combined with a properly adjusted pressure switch will stop the short cycling, reduce your electric bill, and lengthen the life of your pump.

JUGHNE

Submersible pumps like that rely upon being fully immersed in water for motor cooling. So before running dry it also overheats.
Also if dead headed can produce enough pressure to blow your fittings apart.
A pressure relief valve is recommended in the installations, but seldom installed with an adequate pressure tank and working control that can not be isolated from the pump discharge.
FWIW

hot_rod

If you do decide to replace the pump, consider one of the "smart" booster pumps. They adjust to the load and us energy, think ECM circs.

Your tiny pressure tank would be adequate also


https://us.grundfos.com/products/find-product/SCALA2.html

Timco

Nice! I’ll add a huge well tank or two before I change the pump. Need to learn that timeclock too. They have program D set to run zone 13 & 14 in the background which is the tank refill call.

Timco

hot_rod said:

You've already throttled that submersible sprink pump by reducing it two sizes on the discharge Looks like an 1-1/4 discharge reduced to 3/4" ID hose?

If it is grossly oversized for the gpm required, add more sprinklers or larger gpm head Best to buy the correct size pump, as Jamie suggested. Or add a variable speed control.

Either fill the tank faster, or reduce the drawdown flow rate if you are trying to match them better.

Its 1.25” to 1” but certainly reduced.

HDE

Gas engine and battery in a shed with oil soaked wall and floor, too close to combustibles and muffler discharging against it all.
Just wait for the shed to burn down and start over with a better system.

The Steam Whisperer

If you look at the back wall where the sheet metal is, it looks like it has already caught fire once. The plywood looks charred at the top.

Timco

Lol, I will look at that closer when I am back later. The exhaust is extended to the outside. I have the install invoice from the electrical outfit that installed it and the transfer switch a couple years back. What you see is what I bought.

Timco

So next question. When I kick the sprinkler fill well pump on I’m at 5gpm. After 30 min I’m down to 3.5gpm and after an hour I’m at 2-2.5gpm. Since I have no idea what size pump is down there I can see if amps drop off I’m thinking. This is after the well recharged for 3 hours from any use. Does this sound like a pump issue? No air bubbles so I’m guessing not a well issue or not sucking air. Thanks.

Zman

I think that your static water level is probably much higher than the pump. When the pump turns on it has less head to overcome so it is performing lower on it's curve, pumping 5 gpm. The well screen and surrounding earth cannot recover at the full 5 gpm so the level in the well drops over time. As this happens, the pump has to lift the water higher which moves the performance up the curve, reducing the flow rate eventually to 2 gpm.

Does that make sense? I have never tried to explain this before, just checking...

Jamie Hall

Zman said:

I think that your static water level is probably much higher than the pump. When the pump turns on it has less head to overcome so it is performing lower on it's curve, pumping 5 gpm. The well screen and surrounding earth cannot recover at the full 5 gpm so the level in the well drops over time. As this happens, the pump has to lift the water higher which moves the performance up the curve, reducing the flow rate eventually to 2 gpm.

Does that make sense? I have never tried to explain this before, just checking...

Well explained, @Zman . Almost certainly what's happening. The real and serious question for @Timco on this one is -- does the flow eventually settle out and stay at 2 gpm or so, or does it continue to drop? If it continues to drop, there is the potential of running the well dry -- which you don't want, since the pump is water cooled and will fry.

Timco

As always thank you both! It recharges for two hours then has a two hour rest then back on until the float kills it. I’ll check it every 30 min tomorrow for the two hours it’s on. I cut in a tee and a BV downstream and can open the tee and isolate the tank to fill a bucket. The sediment filter barely sees any debris. Well worded and I totally get it.