Another forum (https://terrylove.com/forums/index.php?threads/why-is-pressure-switch-differential-always-20psi.95365/) had this advice: "Any more than a 20 PSI differential will stretch the bladder/diaphragm too far. Anything less than 20 PSI and you don't get the 15 gallons of draw down you normally get from a 50 gallon size tank. Even an 80 gallon tank only holds 20 gallons of water."
I don't think it's correct. I think the "stretch" has to do with the max pressure (not the differential).
Compare these two examples - I say the diaphragm has the same "max excursion" (stretch).
- Differential 30 psi - setting 30/60
- Differential 20 psi - setting 40/60 (a typical setting)
If I'm wrong, has anyone quantified the decreased life expectancy due to increased differential?
I was researching this topic because I wanted to increase the differential from the typical setting to gain some perceived increased pressure (and increased for a longer time period) at house fixtures with only slight increase in risk of "premature" failure of any system components. I was thinking of going to 42/67. (FWIW, I have a brand new WX-255. I also have an Express Water Heavy Metal triple 4.5" x 20" set up.) I'm too used to (consistent) city water pressure.