Lower Cut In Pressure Question

[Chrisdeli]

Hi Everyone,

A quick question regarding well water pump cut in pressure. Would lowering the cut in pressure on a 40/60 pressure switch to say 35/60 or even 30/60 (if it can be adjusted that low) theoretically add life to the well pump? Reason being this would decrease the number of on/off cycles over the life of the pump thus sparing it some wear and tear (since the number of cycles is a main factor in a well pump's life)?

Also- Does a well water tank's air pressure theoretically increase in the summer? If I am measuring the air pressure of the water tank in the winter and the cut in pressure is 40 psi and I measure the tank pressure at 38 psi which is where it should be- will the air pressure noticeably increase during hotter weather so should I fill to say 37 psi in the winter to allow a ~1 psi increase in hotter weather? Hope this makes sense.

Thanks in advance,
Chris

 

[LLigetfa]

Pumps run on a curve producing more GPM at lower pressures and fewer GPM at higher pressures. As such, increasing the cut-out rather than the cut-in will produce a longer runtime. Just don't go overboard and raise the pressure to where the pump can deadhead.

Also some captive air tanks have an internal dome limiter so at some point you could go up against it. If it does not have a dome limiter, you could be stretching the diaphragm.

I would not bother with temperature compensation.

A CycleStopValve might be a better way to reduce excessive pump cycling.

 

[Sponsor]

 

[Reach4]

Air precharge is always measured with the water pressure zero.

Usually air precharge will decrease slightly over time due to air slowly diffusing thru the diaphragm. It is usually suggested to check the precharge annually, tho if you have a butyl diaphragm, every couple of years is good. The average person checks the air precharge never.

Assuming you have a normal pressure switch (no low-pressure cutoff), the symptom of the air precharge being a bit high is a brief stutter in pressure. So not a big deal.

Regarding the bigger differential, you might lessen the diaphragm life due to the bigger stretching.

Yes precharge pressure increases as it gets warmer. Same with your tires, but your tires probably diffuse air a faster.

With cold cold approaching, it is a good time to set the air pressure in your tires if convenient.

 

[Valveman]

Ambient temperature can change the air pressure in a tank. But ambient air is usually about the same in the tank as the water is always the same temp, winter or summer.

When I see a pressure switch adjusted for a wider bandwidth I know someone was trying to reduce the pump cycling. As was said a wider bandwidth can cause problems other than just a wider variation in house pressure. Variation in house pressure, size of pressure tank, and the pressure bandwidth are all moot points when using a Cycle Stop Valve.