Alex Lockhart
New Member
The story:
We moved here from a house with city water about four years ago. The house loses water pressure often enough that it's really annoying (middle of a shower, using the bathroom in the night, on vacation with friends watching the house, etc). Nearly every time it's because the low pressure cutoff switch got tripped. Over the years I've read everything I can find and done lots of adjustments, some of which help a little. Now I have an idea for how to make it "just work" and need your input.
The setup:
We have a 70-foot well in a 6 inch bore, it was tested at around 2gpm just before we moved in. The well pump (3/4HP, 10GPM submersible) fills a 1,000 gallon cistern (black poly above ground, right next to the well house). The well pump is controlled by a no-load sensor and a normally-closed float switch inside the cistern at the top. The cistern supplies the jet pump (1-1/2HP), which pressurizes the house plumbing. The pressure tank is 33.4 gallon (about 9 gallon drawdown @30-50psi), and the jet pump is controlled by a standard Pumptrol 30-50psi pressure switch with low pressure cutoff to prevent running dry if the cistern runs out of water.
The problem:
A few times a month, or occasionally several times a week, the low pressure cutoff switch gets tripped, so we have no water pressure. All we have to do is run out to the well house and switch it back on, and the jet pump runs normally again. Aside from a few times when the cistern was actually out of water (watering the lawn too long, or once when the well pump failed and was replaced) the jet pump just starts working again for another week or three. It seems like something causes the pressure to drop momentarily to trip the switch, but I can't figure out why, as the cistern has plenty of water. I've replaced the pressure switch a few times when the contacts fused, and several times I spent a few hours measuring and adjusting the pressure in the switch and the pressure tank to get them tuned for each other. Getting the pressure tank precisely between 2-4psi below the switch cut-on pressure seems to lessen the frequency of the low pressure switch getting tripped, but it still happens too often.
The idea:
If I install a normally-open float switch at the bottom of the cistern and wire it to the jet pump, it would shut off the jet pump when the cistern is almost empty. Then I could replace the low pressure cutoff switch with a regular pressure switch. The jet pump would provide water pressure anytime there's water in the cistern, and be protected from running dry by the float switch at the bottom of the cistern. As a bonus, in the rare event that the cistern runs out of water, then the float switch would automatically turn the jet pump back on when there's water in the cistern again - without us having to flip the switch back on.
The questions:
Is there any reason why using a float switch in the cistern wouldn't be an effective safety cutoff for the pump, or wouldn't be reliable? Aside from the increased cost and installation work, why wouldn't our system have been originally set up with a float switch instead of low pressure cutoff switch, given that the jet pump is pulling from the cistern and not directly from a well? Is there anything else I need to be aware of before making this change?
Thanks!
Alex
(Cross-posted to doityourself.com forum)
We moved here from a house with city water about four years ago. The house loses water pressure often enough that it's really annoying (middle of a shower, using the bathroom in the night, on vacation with friends watching the house, etc). Nearly every time it's because the low pressure cutoff switch got tripped. Over the years I've read everything I can find and done lots of adjustments, some of which help a little. Now I have an idea for how to make it "just work" and need your input.
The setup:
We have a 70-foot well in a 6 inch bore, it was tested at around 2gpm just before we moved in. The well pump (3/4HP, 10GPM submersible) fills a 1,000 gallon cistern (black poly above ground, right next to the well house). The well pump is controlled by a no-load sensor and a normally-closed float switch inside the cistern at the top. The cistern supplies the jet pump (1-1/2HP), which pressurizes the house plumbing. The pressure tank is 33.4 gallon (about 9 gallon drawdown @30-50psi), and the jet pump is controlled by a standard Pumptrol 30-50psi pressure switch with low pressure cutoff to prevent running dry if the cistern runs out of water.
The problem:
A few times a month, or occasionally several times a week, the low pressure cutoff switch gets tripped, so we have no water pressure. All we have to do is run out to the well house and switch it back on, and the jet pump runs normally again. Aside from a few times when the cistern was actually out of water (watering the lawn too long, or once when the well pump failed and was replaced) the jet pump just starts working again for another week or three. It seems like something causes the pressure to drop momentarily to trip the switch, but I can't figure out why, as the cistern has plenty of water. I've replaced the pressure switch a few times when the contacts fused, and several times I spent a few hours measuring and adjusting the pressure in the switch and the pressure tank to get them tuned for each other. Getting the pressure tank precisely between 2-4psi below the switch cut-on pressure seems to lessen the frequency of the low pressure switch getting tripped, but it still happens too often.
The idea:
If I install a normally-open float switch at the bottom of the cistern and wire it to the jet pump, it would shut off the jet pump when the cistern is almost empty. Then I could replace the low pressure cutoff switch with a regular pressure switch. The jet pump would provide water pressure anytime there's water in the cistern, and be protected from running dry by the float switch at the bottom of the cistern. As a bonus, in the rare event that the cistern runs out of water, then the float switch would automatically turn the jet pump back on when there's water in the cistern again - without us having to flip the switch back on.
The questions:
Is there any reason why using a float switch in the cistern wouldn't be an effective safety cutoff for the pump, or wouldn't be reliable? Aside from the increased cost and installation work, why wouldn't our system have been originally set up with a float switch instead of low pressure cutoff switch, given that the jet pump is pulling from the cistern and not directly from a well? Is there anything else I need to be aware of before making this change?
Thanks!
Alex
(Cross-posted to doityourself.com forum)