Advice for house pressure from a cistern system

[ubercolin]

I have an off grid cabin with water supplied by a cistern (which is in turn filled by a solar well pump). The cistern is gravity fed to the house via a small drop (20ft?). The house pressure was set up 10 years ago using an Amtrol RP-10HP. Recently the pump has started to cycle frequently when using water, with the pump giving a rapid cycling error. This leads me to believe that the tank bladder has become waterlogged and needs to be replaced.

As I started researching replacing this, I’ve started to wonder whether the current setup is the right system. Specifically, when the plumber initially set up the system, we could never get the pump to have a cutoff above 40psi (the pump would continually run if we set it higher), presumably because the pressure from the cistern is so low? So it was configured with a cut-in of 30psi and a cutoff of 40. We’d love to be able to get slightly higher pressure, but it also is workable as is.

So my initial question is, assuming that I need to replace the tank, is this system with the pressurizer even the right setup, or should I be thinking about something like a jet pump (or something else)?

Thanks for any advice any of you might have…

 

[Valveman]

Nothing really "solar" about the Amtrol RP-10HP. It is just a regular 1/2HP jet pump. That pump can only build 57 PSI max. Probably working with a 40-50 pressure switch setting on the Guardian pressure switch. That means your pressure is an average 45 PSI as the pump cycles on and off between 40 and 50 PSI. The Guardian with only 10 PSI between on and off instead of the normal 20 PSI requires twice as large a pressure tank for the same draw down. 10 PSI between on and off also cycles the pump and tank bladder twice as much as usual, which is why the tank bladder is bad. Funny thing for a tank manufacturer to make a device that requires twice the size of pressure tank and wears out tanks sooner. Lol!

If you get a pump like the Goulds J5SH is will build 83 PSI max with the same 1/2HP load on the electric system. That would work with a 50/70 pressure switch setting, which is a 50% increase in pressure. The pump will still cycle on/off between 40/60 or 50/60 if you continue to use the Guardian switch. Pressure is always weaker during the part of the cycle when the pump is off and water is coming out of the tank. Adding a Cycle Stop Valve would deliver a strong constant 60 PSI and you would no longer even need soap in the shower. The CSV would also work with a much smaller tank. I would use the 10 gallon size pressure tank with the 50/70 switch and the 4.5 gallon size tank with the 40/60 switch setting or lower. Since you are already needing a new tank this would be a good time to look at the PK1A kit that comes with a new tank and the CSV1A Cycle Stop Valve and everything else you need.

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[Valveman]

You could also use a multi-stage and get even more pressure, even with just the 1/2HP motor. The 5GB05-9 would work with a 80/100 pressure switch and the CSV delivering a strong constant 90 PSI. You can have as much pressure as you want, as it is your water system. You just have to make it happen.