Feb 9, 2012, 7:01 AM
Just as Robert found out, bringing US ways of doing things to Mexico doesn't always work - or said another way: Mexicans do sometimes know what they are doing. You propose 60 psi as the standard, while Mexican pressure systems are typically set up at lower values: between 20 - 35 psi. e.g. If you buy a pump here, without a pressure switch, the common pressure switch sold here in Yucatan operates at 24 psi.
I've only set up 4 hidroneumaticos, and only worked on another 3 systems with them, but very consistently we've found that when installing a hydropneumatico on an existing tinaco gravity feed system: typical Mexican plumbing materials, joints, and connections leak significantly if you pressurize them to more than 35 - 40 psi. When retrofitting tinaco-gravity-feed systems with pressure pumps, the leaks have occurred under floors, inside walls, and in places that were difficult to access and required some demolition of pretty one-of-a-kind tile etc.
Given the potential for leaks, demolitions, and repairs, it just is not worth it to try to crank up the pressures to 60 psi US municipal standards, and instead we find it better to default to US rural home-well conditions of 30 psi or less. Our customers have found that a range of 20 psi - 30 psi meets most of their needs without creating leaks. This is enough pressure to fill a washing machine fairly rapidly, and provides reasonable shower pressures.
If you buy a hidroneumatico here in Mexico, we also recommend using the 2 adjusting nuts to get approximately a 4 psi working range of pressure under 30 or 35 psi - and adjust the air pressure in the bladder/diaphragm to within 2 psi of your lowest pressure. e.g. if you have a working range of 25 psi when the pump kicks-in and pump shut-off at 30 psi, then adjust the air pressure in the bladder/diaphragm to 23 - 25 psi. ** Hint: We've found most Mexican plumbers do not know how to make these adjustments.
Overall, I very much agree with Papirex's advice, but there are many instances where good NOB theory doesn't fit Mexican realities.
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(This post was edited by YucaLandia on Feb 9, 2012, 7:07 AM)