Pressure Regulating Valve before one tap with Instant Hot tank

[Geniescience]

Many are sold without PRV.
Some are sold with a PRV.
Do you recommend it ? Highly or partially ?

E.g. without http://www.anaheimmfg.com/products/hotwater/hot_water.html "Quick & Hot"
E.g. With it: http://waterstoneco.com/p-standard-hot-tank.cfm "Quick & Hot" and new label too

An instant hot tank is open vent, so it's unpressurized in the sense that boilover has an escape route through the teflon hose to the spout. ( Y / N ? )

The flow into it is what pushes hot water out.
Is the pressure of that flow a significant factor?
What else is there to know?

 

[hj]

What would be its purpose? I have NEVER installed a PRV on an "InstaHot" unit, and have never seen one sold with one.

 

[Sponsor]

 

[Storm rider]

The specs for that Waterstone unit call for max 60 psi input, so I assume that they include the PRV to protect the unit in case your house pressure is higher.

 

[hj]

The "pressure" is applied to the faucet. There is very little pressure in the tank when the water is flowing.