since check valve holds water in the line can a hand pump be installed between the check valve and water tank?
The easiest way is to install two pressure gauges (If reducing pressure) either side of the reducing valve, you will then have indication of upstream pressure and down stream pressure, of which you can adjust to suit you process.
You'll need to install a tee into the line by the fuel filter to check it, there is no shrader valve.
no
no
Install a pressure reducing valve
There is no difference between check valve and NRV, both are same
Codes vary, check max. press. allowed in home, if press. higher than allowed by code coming into home, than install pressure red. valve.
pressure relief valve relief the excess pressure which is developed in the syatem, while pressure reducing valve reduces the pressure and supply it to the system.
No
Check valve
Need more info - what is it for? What is the size of the pipe and the pressure differences you are trying to get?
You have to fabricate fittings to splice into the fuel line at the fuel filter so as to install a fuel pressure gauge. Not uncommon to do with older vehicles.