Advice please on installing a Square D 30/50 pressure switch with low pressure cut off.

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Charrie

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So i have had this switch for a couple of years now and when the well house was replaced, the well company that did the work said: NO you don't wan't to install that switch. You will spend a lot of time running back and forth to reset the switch.
I have lived here 4 years now and we have only lost power maybe 4 times. The well has never ran dry and seems to always cycle with the current 30/50 switch. I just want to add a little protection for the pump in case for some reason the well went dry.
Any advice is appreciated!

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Charrie
 

Valveman

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Low pressure cut off switches can be a nuisance as they usually need manually resetting after every power outage. They are also not a completely reliable way to protect the pump from running dry. The Cycle Sensor is a reliable way to protect the pump from running dry and will reset itself every time the power comes back on. https://cyclestopvalves.com/pages/cycle-sensor-pump-monitor

 

LLigetfa

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I agree with Cary. A low cutoff is not comprehensive protection for run-dry. A well can run dry after you stop using water but the pump is still running, trying to refill the tank. Contrary to what many folks think, a submersible can lose prime and melt down. When there is no water use during refill, the pressure will not drop below the cutoff until after the damage has been done.
 

Reach4

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If the low pressure cutoff makes you feel better, and since you have it, you could try it. If you get the occasional nuisance trip without the power having gone off, drop the air precharge in the pressure tank a bit.

I think it was LLigetfa who modified one to disable that feature. But he is more adept at modifying stuff than most.
 

LLigetfa

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If you get the occasional nuisance trip without the power having gone off, drop the air precharge in the pressure tank a bit.
It would be fine if it were just nuisance trips but in reality, it can leave a false sense of security and result in a pump meltdown. If protection is worth doing, it is worth doing it right.
 

Charrie

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Thanks for the advice and information about the Cycle Sensor. It looks like a great piece of equipment to protect the pump. After watching the video if I understand correctly, it senses the amperage. If the pump is dry, it will use very low amperage.

Ah, so if the pump were to be filing the pressure tank and and runs dry while the pressure switch is above the the safety shut off pressure or the actual shut off pressure of the pressure switch, the pump can be dry but still hold the pressure above the those limits until it burns up. . I see.

The Square D switch I have would only protect the pump if the the well ran dry while using water or a pipe busted and the well were to run dry due to the leak.

Two more questions please.
1- My well is 300 feet from the house and wired with 10-2 with a ground. I do not know what size my pump is. Can I use a amp meter to determine the size pump?
The drop pipe is 3/4 poly and according to the company who drilled most of the wells around here, may be 180 feet deep but that is a unknown. Anyway the FLA is 5.8 on both legs when running.

2- Is a 3/4 drop pipe ok? I am fine with the pressure in the house and the pressure switch is set to 30/50. I am more concerned about the affects of the pipe size on the pump and if the pipe should be replaced with a larger pipe when the pump is replaced later on.

Thanks
Charrie
 

Valveman

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It's a 1/2HP and the 3/4 pipe should be fine. The 3/4 pipe will have some restriction at maybe 10 GPM. A house rarely uses more than 5 GPM. If you do any irrigation over 10 GPM you may need a larger pump and larger pipe.
 

Charrie

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Thanks Valveman!
Maybe one more question.
The well was drilled around 2000 but I know nothing about the current pump until today. Now I know its a 1/2hp. Would it be advisable to save up some money and invest in a spare pump to have on hand? That way if the pump were to go out on a holiday weekend I'm not stuck paying what ever the price would be.
I mentioned this to the local hardware story that has quite a large selection of pumps and well supplies. He said to wait because the warranty starts the day I buy the pump.

Thanks
Charrie
 

Reach4

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What size is the well casing. I presume that is PVC and is either 4 inch (4.5 inch OD) or 5 inch (5.563 inch OD). So as Ace said, you can get 2-wire 1/2 hp 10 gpm pumps pretty readily. If you needed 1/2 hp 7 gpm to get the needed pressure, those are rarely stocked locally I would expect.

I said 2-wire because that does not need a control box.

If you had a 4 inch steel casing (unlikely), you might want a 3 inch SQ pump. You won't find those locally either.

When you store pumps for long times (I think they say more than 2 years), they can dry out some, and you should open them up to top up with distilled water.
 

Charrie

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Thanks Reach4.
It is at least 5.563 OD PVC. One of the videos I watched said to always test your pump before installing it. Makes great sense! I have a creek between the well and house that has pretty good flow most of the year and a 3' deep area I could always test a pump in unless that's a problem with bacteria or picking up trash in the pump.
 

Valveman

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Thanks Valveman!
Maybe one more question.
The well was drilled around 2000 but I know nothing about the current pump until today. Now I know its a 1/2hp. Would it be advisable to save up some money and invest in a spare pump to have on hand? That way if the pump were to go out on a holiday weekend I'm not stuck paying what ever the price would be.
I mentioned this to the local hardware story that has quite a large selection of pumps and well supplies. He said to wait because the warranty starts the day I buy the pump.

Thanks
Charrie
Not only will the pump be out of warranty when you finally install it, but the water in the motor will leak or evaporate out. With even a small loss of water from the motor it will not last long after installed. For a pump/motor that has been in storage for a few years, the water in the motor needs to be topped off and the pump tested before installing it. The warranty issue is really secondary to the loss of water in the motor.

A 1/2HP, 10 GPM pump is very common and you should be able to find one when needed. But if it is a different 7 or 5 GPM pump you may want to keep a pump end on the shelf and just buy a new motor for it when the time comes. The pump end has not lubricant or coolant in it and can be stored for as long as you want.
 

Charrie

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If it is a 7 or 5 GPM, why couldn't it be replaced with a 1/2hp 10G PM?

I had no clue that there was water or coolant inside a pump motor! If I had pulled a pump and water came out of the motor, I would have thought it was bad! My big lesson for the day! Thanks Valveman.
 

Reach4

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If your water is too deep, a 10 gpm is not strong enough. But I think your water is not very far down, so 10 gpm would be fine.

7 gpm would have more stages.
 

Valveman

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If the water in the well is less than 150' deep the 10 GPM, 1/2HP will work. If it is really 180' you will need the 7 GPM pump. But in a bind and picking up something that would work and is available, a 3/4HP in 10 GPM series will work at that depth.
 

Reach4

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Note that if you are pumping more GPM, you probably want a bigger pressure tank or a CSV.
For the 1/2 hp 10 gpm pump characterized in the chart below, if running 40/60 psi, I think this would be OK for a pump at around 80 ft.

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