Shallow well pressure switch chattering

[Rslaback]

Last year I drove a 2" well point to service a single hose bibb. The primary purpose of that well is a drip irrigation system for 12 fruit trees and 18 blueberry plants. It also now serves about 250' of soaker hose for a sweet corn patch.

The pump is a Red Lion RJS-75-PREM with the integrated pressure switch. As it was only feeding a single bibb I installed the pump to the top of a 7 gallon pressure tank. When it was first installed I found that when the orchard watering timer would come on the pressure drop was enough that the pump would kick on but the pressure switch would chatter. I imagine this is because of the large amount of water from the pump trying to get through the 3/4 pex and then almost instantly filling the pressure tank. I was able to fine tune my pressure switch to stop this behavior.

However, this past summer I had to add in a couple of motion activated sprinklers to keep the deer away from the squash my wife added. They each fire for up to about 10 seconds which causes the same issue I had before where the pump switch chatters.

I have thought through some possible solutions but I wanted additional input from the more experienced:

1. Move the pressure switch pick up so that it does not come off the housing of the pump. I imagine if I move it down stream away from the instantaneousness of the pump kicking on that might work.

2. Add in a second tank to the system. A larger amount of water to displace before the pump cycled would I imagine help. There isn't a ton of space in the current installation location but I imagine I could work something out.

3. Swap out the pressure tank with a larger unit. Same rationale as above.

What say you experts?

 

[Valveman]

Chattering just means the pump is cycling on/off really fast. Moving the pressure switch closer to the tank will stop the chatter, but not the cycling. Adding a Cycle Stop Valve CSV1A will give you a place to attach the pressure switch and will stop both the chattering and the slower cycles which are still damaging the pump.

 

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[Reach4]

As a workaround, you might be able to set the pressure switch differential higher.

Also, changing the sense tube going to the pressure switch and extend close to the tank could do it. Same effect as moving the pressure switch, but you don't have to actually move the switch.

 

[Bannerman]

The pump maybe createing pulsations which the pressure switch is sensing by being connected directly to the pump

As the pressure tank will absorb and even out pulsations, by connecting the pressure switch to the tank inlet/outlet, the switch will be subjected to more consistant pressure.

 

[LLigetfa]

Pressure sense lines are connected to the pump as a DIY convenience, not as a best practice. A pump used with a single hose bib and/or drip irrigation could cause excessive cycling so Cary's advice to add a CSV and to relocate the pressure sense line to the port on the CSV will not only stop the chattering but also stop excessive cycling.

Alternately, connecting the sense line to a port on a proper tank Tee would end the chattering.

 

[Rslaback]

I hate to bump this one back up guys but I need some more help. I was able to fine tune my switch last year with a combination of lowering the range switch as much as possible and raising the differential switch as high as possible. So the pump kicked on extra low and then shut off at pretty much max psi for my system. It worked OK after that.

However, this spring I ran into issues. First I found the pump on when it shouldn't be. Even after a re-prime I couldn't get it to pump anything so I swapped in a different pump I had on hand. The dissection of the old pump showed a separated impeller which had been eaten by the diffuser. In the meantime I found that the replacement pump wouldn't keep a prime as well. My system is a 1/2 or 3/4 jet pump (depending on which is in there) sitting on top of a 7 gallon horizontal tank going out to a single outside spigot for plant watering on timers. I also moved my pressure switch tap off the pump housing to about 3 feet down my output line which did help in being able to use the pressure tank to prevent chatters.

I swapped over to a pressure switch with a cut off in order to prevent another pump failure but it seemed like each time the check valve would open the pressure would drop enough to kick that out so I abandoned it.

I did eventually figure out that my issue was actually my check valve that was plumbed in right before my pump. The o ring had distorted from use and was sticking to the seat. This increased the force required to pop it open and the pump couldn't do it by itself.

I have a new check valve in now and I'm not seeing much better results. With the system charged up, half the time when the pump kicks on I get chatter and it seems the pump about half of the time doesn't recover from that, pumps all the water out and I end up with a pump running empty again.

All of this to say, how likely is it that my issue is actually just not enough buffer in the 7 gallon tank? Or it is too much restriction from the line from the pump being 3/4 instead of 1"? Or both? Or neither?

Right now the full system is a 2" driven slotted point, 26 feet into the ground with water hit at 15. The soil is sand and the well is within 100 feet of a lake so it isn't pulling dry. The 2" comes up to a tee and reduces to 1 1/4 before going into my building above ground. Right inside it goes through a poppet check valve, through a union and then turns 90 to go into the pump. The pump output necks from 1" down to 3/4" and goes around and down the wall with a tee sending one leg to the spigot and the straight onward to the pump.

I know that above it was recommended that I put a better monitor on the system but would that actually solve my problems? At this point I am less worried about the pump coming apart than I am about having a reliable system.

 

[Valveman]

When you turn up the pressure switch to the max or almost the max pressure a jet pump can build, it isn't flowing enough water to stay cool and the impeller melts down as you have seen. A 7 gallon tank only holds 1.5 gallons of water. This is enough if you have the sprinklers match to the max flow of the pump to stop cycling. But without enough sprinklers running it can cause a pretty rapid cycle. It won't be as fast as a chatter, but close. Chatter is still caused by the pressure switch not being cushioned by the tank. Either the lines are too small, the tank too far away, or both.

A Cycle Sensor is the best way to protect a jet pump from running dry. But it also looks for a rapid cycle and will shut the pump off if you don't solve the chatter.

 

[Reach4]

Item 1, and maybe 2, in your first post should help the pressure switch from chattering.