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Moomanji

New Member

1

Monday, July 11th 2016, 4:50pm

Pressure switch issue

I have an irrigation well with a Square D pressure switch (new as of last year). I'm having an issue with the switch being inconsistent. It's supposed to cut off at 90psi (by the gauge), and does most of the time. But sometimes it is cutting out anywhere between 86 and 95psi. Unfortunately this is a problem because I'm trying to do some macgyvering between system flow and a pressure relief valve that is much more precise than the pressure switch. It's a hokey setup but it may solve a short cycling problem I'm having

Is this just the way these switches are? Are there more precise switches available for 110v?

Wet_Boots

Supreme Member

Posts: 5,147

Location: Metro NYC

2

Monday, July 11th 2016, 7:33pm

What model number is the switch? The entry level ones are not reliably settable for cutoff pressures as high as yours.

If your sprinkler heads can be adjusted or re-nozzled, you might get your pressure balance at a much lower number.

Moomanji

New Member

3

Monday, July 11th 2016, 9:02pm

I can get the model number tomorrow. Big issue is we've been burning out contactor components due to short cycling on the pump. We're pushing about 85psi out about a half mile out up about 30ft elevation at the end, ideal flow is around 100GPM. The irrigation at the end high point can't deal with less pressure, especially if we run two or more valves at a time. The ideal flow/pressure for our pump is about three valves/zones in our design. Balanced between four irrigation clocks with between 6-11 zones each and different run times, it's a bit a nightmare.

A irrigation head change out may be an option, though expensive. I'm concerned about the pipe loss at that end regardless.

This post has been edited 1 times, last edit by "Moomanji" (Jul 11th 2016, 9:22pm)


Wet_Boots

Supreme Member

Posts: 5,147

Location: Metro NYC

4

Tuesday, July 12th 2016, 6:55am

You may already have a higher grade of pressure switch. It's the smallest ones that top out around 80 psi. What do you have for pressure tanks? Nothing like a row of big pressure tanks to increase cycle times. Yeah, they cost money, but they are the brute-force solution to short cycle times.

Moomanji

New Member

5

Tuesday, July 12th 2016, 12:48pm

Only one pressure tank, I don't know the exact size offhand. We could probably add one additional tank of the same size, but that's about it. It's a small room. I couldn't find a model on the pressure switch. Here's a photo of the pump house setup:


Wet_Boots

Supreme Member

Posts: 5,147

Location: Metro NYC

6

Wednesday, July 13th 2016, 9:29am

That's the heavy duty pressure switch, so it should be able to function in your pressure range. What is the pump horsepower and operating voltage? What is the rating on the pressure tank?

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