I'd like to ask best way for real installation which means reliable, safe and easy for maintenance.

I thought 2oo3 Solenoid, but it's not easy to install in the field.

Hope you're sharing ideas.

 

There are several solenoid packages commercially available that provide redundant solenoids. Please see:

ASCO 1oo1HS, 2oo2D:
http://www.ascovalve.com/Common/PDFFiles/Product/RCS_V7363R3.pdf

Tricocex 2oo3:
http://www.triconex.com/us/eng/triconexProducts/tmr/default.htm

William (Bill) L. Mostia, Jr. PE
WLM Engineering
This information is provided on at caveat emptor basis.