Well pressure tank switch

NHmitch · Aug 10, 2012

Hi,

We have a deep well, and we use a pressure tank with a pressure switch, and the tank normally gets to about 60psi before the switch shuts off, but lately the switch is has not been working when it should. It is pretty corroded. The question I have is how do I know what switch to buy to replace the one that is bad. The switches come in 40/60psi, or 30/50psi, or 30/5 psi. They all look the same, and my tank is about a 35 gallon pre-charged tank, that is charged to about 40psi. Should I check the tank pressure, and if it is low, can I fill it, and will that correct the problem, without installing a new switch? Thanks, I really do not know a lot about this system. I know that the gauge is very rusted, and I want to replace it, but that is also under pressure, so I am not sure how to change that. Thanks in advance for any help that you can offer with this! This is the switch that I was looking at: Water Source Switch Pressure, 30/50 PSI - 1028052 | Tractor Supply Company

Mark Page · Aug 10, 2012

I would take everything that needs to be replaced to the largest plumbing supply house around and have them sell you replacements. A flooded basement or no hot water in the morning
is no good. To me, the peace of mind makes it worth the cost. When it comes to water, gas or electricity you don't want to cut corners.

randy41 · Aug 10, 2012

new switches are not expensive and are easy to install. turn off the power to the pump and open a valve somewhere so when you remove the old switch you don't get a small flood. sounds like you need to buy a 40/60 switch. the air pressure in the tank should be just below 40 when you check it with a tire pressure gauge. wire the new one like the old one.

BeezFun · Aug 10, 2012

Every pressure switch I've had is adjustable for both high and low pressure. I'd look for something like that so you can tweak it.

turnkey4099 · Aug 10, 2012

Randy is right. It sounds like you need a 40/60. Actually either will do, you just need to readjust the precharge tank pressure to agree with the one you install. If you do a lot of irrigation 40/60 is best, some impulse sprinklers get cranky with 30/50. Precharge is set 2 psi belowthe cut-in pressure.
It is checked with the tank empty...or as empty as it can get, i.e., turn off power, open two faucets, one the lowest one you can find in the house, the other somewhere above that one, higher the better. When the wter stops running from the bottom one, check the precharge and adjust as required - there is a schrader valve on top of the tank for that purpose.

Make a careful diagram of the wire locations on the old pressure switch before you disconnect so you will know how to install the new one.

Also pull the small 1/4" riser tube the switch is on and clean it out - mine got so plugged the switch couldn't feel the pressure.

Harry K

NHmitch · Aug 10, 2012

Thank you guys for the excellent advice! I am going to try the tests that you have listed, and if I need to, I will get the correct 40/60 switch. Again, I really appreciate the help!