Using Sprinklers On A Well & Avoiding Short Cycling

[NEMatt]

Now that could be interesting. I suppose I could just connect the hose out a window straight from the well tank tee. Still not like mega flow through that but maybe better than the frost-free bib.

This is just for this season of seeding some bare spots and overseeding others. Not really in the market for a permanent solution.

 

[NEMatt]

Well, barring improvements to my spigot setup, I've just been using my one tripod impact sprinkler and moving it around. Running solo its actually doing decently well. Right now I've decided to let the well pump run three times then shut it off and move sprinkler positions to run later.

It's something on the order of 70 seconds run time and 2.5min drawdown. That going to smoke anything?

 

[Sponsor]

 

[LLigetfa]

I suppose I could just connect the hose out a window straight from the well tank tee.

I cut an access through the rim joist so that I can run hoses into or out of the crawlspace where my sump pump, pressure, contact, filter, and softener tanks are. I just cut the back off of a cast aluminum outdoor electrical box and put a blank cover on it. If/when I need to run a hose in or out, I just take the cover off and pull out the insulation.

Also, I piped in several frost free hose bibs around the house, some just iron filtered and others hot and cold softened water. I ran pipe underground to the garden as well. I can easily draw as much water as my pump can deliver. With no water use, my pump takes around 2 1/2 minutes to refill my tanks. I trend my pump cycles with software and usually average around 16 cycles per day. That number is much higher when watering gardens.

 

[Bannerman]

It's something on the order of 70 seconds run time and 2.5min drawdown.

Only 70 seconds to fill the pressure tank at the same time the garden hose is running indicates your pressure tank is too small for the capacity of your well pump. The proper size pressure tank should cause the pump to operate between 60-120 seconds to fill the pressure tank while no water is being drawn.

To eliminate cycling without increasing the pressure tank capacity, consider adding a Cycle Stop Valve to your exsisting well system as Valveman suggested in post #5.

 

[NEMatt]

Only 70 seconds to fill the pressure tank at the same time the garden hose is running indicates your pressure tank is too small for the capacity of your well pump. The proper size pressure tank should cause the pump to operate between 60-120 seconds to fill the pressure tank while no water is being drawn.

I am am pretty sure it is underfilled by probably 5 psi. During my water treatment install a few months ago I had topped the pressure tank up to 2 psi below what the tank tee gauge read at cut in. Only later I installed a few new pressure gauges and realized that one read low by a fair bit. Havent gotten around to draining and adding more air. Without water running it takes about 45 seconds to fill currently.

 

[Bannerman]

pretty sure it is underfilled by probably 5 psi.

That would not change the pump run time. If your pressure switch is calibrated for 40 psi cut-in and 60 psi cut-out, the pump will continue to be activated and deactivated at those pressurese so the amount of water added by the pump will be the same. With only 33 psi instead of 38 psi as the pre-charged pressure, then there will be a greater amount of water remaining in the tank when the pump is activated at 40 psi.

 

[LLigetfa]

That would not change the pump run time.

Maybe yes, maybe no, depends on whether the tank has an internal limiter dome. If it does, the bladder is stopped by the limiter and the last few PSI rise very quickly with very little extra water stored.

 

[NEMatt]

Doesn't having the tank undercharged cause less drawdown before the pump cuts back in? If less water needs to be replaced, the pump would run a shorter amount of time right?

 

[Bannerman]

With the pressure switch calibrated to 40/60 psi, the pump will continue to become activated at 40 to add whatever amount of water is needed to raise the pressure to 60 to cause the pressure switch to shutoff the pump.

If the amount of precharge is drastically too low, then there will be insufficient compressed air in the tank to push the full amount of water out from the tank so the plumbing pressure will fall very rapidly, causing the pump to become activated very quickly once water begins to be consumed. This does not appear to be ocurring with your 5 psi lower precharge as your tank supplys 2.5 minutes drawdown before the pressure falls to 40 psi.

What is occuring is the tank pressure is rising from 40 to 60 within only 70 seconds even though the sprinkler is operating during that time. If the sprinkler was not running, the pump would likely run for only ~30 seconds to raise the pressure from 40 to 60.

What is the capacity or model number for your pressure tank?

 

[NEMatt]

Its a 44gal wellxtrol. So I think that should be like 11 odd gal draw down if all is good.

It runs for about 45-50 sec with no water usage.

 

[NEMatt]

If I went ahead with this high flow silcock https://www.amazon.com/gp/product/B..._title_srh_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER is there anything that would stop me from just using something like a Falcon Stainless flex hose right to the 3/4FIP on the back of this and through the rim joist? I ask because the existing hose bib is in a terrible location in the basement for accessibility. It's sort of up behind one of the transverse beams all tucked away near a hydronic pipe. If I didn't use flex it would require like 4 elbows to mate to my PEX line and I cant get my crimper up in there. If I did use flex hose... far less worky.

 

[LLigetfa]

You could always make the last crimp outside and then tuck it back in the hole.

 

[NEMatt]

Well I installed that full flow quarter turn ball valve listed above. I can now run two impact sprinklers effectively, however it is still not enough to keep the pump cycling all the time. I am at about 2:45 on, 1:35 off.

I fear with the PEX run and hose length/diam, I am going to run out of PSI at the end of the hose to keep the sprinklers running properly before I can gang together enough sprinkler flow rate to keep the pump running all the time. You can tell they get a little unhappy around cut-in pressure. Impacts get a bit soft.

 

[Valveman]

Well I installed that full flow quarter turn ball valve listed above. I can now run two impact sprinklers effectively, however it is still not enough to keep the pump cycling all the time. I am at about 2:45 on, 1:35 off.

I fear with the PEX run and hose length/diam, I am going to run out of PSI at the end of the hose to keep the sprinklers running properly before I can gang together enough sprinkler flow rate to keep the pump running all the time. You can tell they get a little unhappy around cut-in pressure. Impacts get a bit soft.

That is exactly the problem a CSV is designed to solve. The CSV will let you run just one sprinkler without the pump cycling. As you can see there are always reasons it is almost impossible to make the sprinkler system match the output of the pump. With a CSV as long as your using more than 1 GPM the pump never cycles at all.

 

[Reach4]

Well I installed that full flow quarter turn ball valve listed above. I can now run two impact sprinklers effectively, however it is still not enough to keep the pump cycling all the time. I am at about 2:45 on, 1:35 off.

Increasing the pressure switch setting, maybe to 55/75, along with raising the air precharge accordingly, may improve that.

The CSV would make that tuning unnecessary.

 

[NEMatt]

Yeah I realize a CSV would be perfect in this application. I am just a bit apprehensive about building that much backpressure in a 45 year old well, in which I don't really know the piping condition etc.

 

[Valveman]

Yeah I realize a CSV would be perfect in this application. I am just a bit apprehensive about building that much backpressure in a 45 year old well, in which I don't really know the piping condition etc.

Back pressure is good for a pump, cycling on/off is not. The well won't see any back pressure, just the pipe the pump is hung on. That pipe should be plenty strong to handle the back pressure or it wouldn't hold the weight of the pump either. Model number or amps of the pump since we already know the flow is about 15 GPM and I could tell you what the back pressure would be. My guess is about 100 PSI , which isn't much more than you see with a 40/60 pressure switch by itself.

 

[NEMatt]

Unfortunately not a clue on the pump specs. 1977 as-built info shows a 10GPM Red Jacket 1/2hp placed at 200ft. Minor miracle if it is still the same pump after all these years I would think.

 

[Valveman]

A 10 GPM, 1/2HP pump can only build about 100 PSI max. And they will usually do that until the day they die.