Isn't the pressure set by the company that makes the pump?. I know you can get different volumes in GPH. I would think the pressure
settings would be very similar.

Ok, l meant yachts, and l was wondering about the systems on yachts.
This particular one has a 1/2 inch hard-hose system, (black non bendable half inch hose fitted to the yacht while from the tank to the pump 1/2 inch soft hose) galley, bathroom, shower, non electric hot water system. Run engine for hot water or it is all cold.

Could one fit a 9 litre/min pump with 50psi pressure instead of 25psi? The new pump comes with two possible pressure switches.
Having a 25psi pump removed, would the new one with a 50 psi pressure switch blow the system to kingdom come or not. According to my limited physics knowledge - l might be totally wrong - the pressure at the tap or shower head would quadruple.
Would a system handle this pressure or not?

The foot pump - on the picture - has been disconnected. The water runs from the soft hose into the hard black hose without any apparent problem.

Could l run higher pressure - up from 25 to 50 psi - without damage?

Low pressure plumbing, boats or caravans don't like anything over 30psi. My guess is you pushing your luck going
as high as 50, if your system is standard low pressure, better stick with that.

Household pressure in NSW is 20 psi.

cisco said..
I am sure if you have plumbed up correctly and securely clamped the hoses, the hose you have there will handle the pressure.

The thing to think about with pressurised water systems is that if it is left on and a joint develops a leak or blows off, the pump will dump all your fresh water to bilge.

I adhere to the KISS principle and do not have a pressurised water system. The right foot pumps will do the job just as well and leave both hands free.

If you have a hot water system that runs off waste heat from the engine, consider that the water can be up to 80 degrees in temperature. That means you need to look at the operating temperature ranges of the pumps and hoses you are using.

With the right ingredients you can have your cake and eat it.

I work on the ktwh (keep the wife happy) principal and have a pressurised, hot water system. The system heats of the engine, and yes it can run very hot. You need to be careful as the water is hot enough to burn.

Cisco, out of interest, what are you doing in the shower that needs both hands kept free.................

It is not a wife thing, l solved that problem years ago ('libera nos a malo'!), this system came with the yacht.

The old pump chucked it in, it got replaced with the one on the pic, same pressure 25 psi. l think it is what you call head pressure.
It works fine - though, it blew the foot pump, which l disconnected. The foot pump needs a direct connection to the tank, instead of running the pressure thorough it. l seldom leave the system pressurized.
I was just wondering what pressure those systems working at.
Larger flow rate would empty my small tanks too soon but l could do with a bit more flow at the shower head.

The hot water gets pretty hot after running the engine for hours.

Thanks for your inputs!