Pump outlet valve orientation

[The Judge]

does the distance between the pump and the outlet valve matter that much?

If you've got stainless or copper piping then it doesn't make a lot of difference. It's good practice to put the throttling valve immediately downstream of the pump discharge. Putting the valve further away from your pump when using silicon tubing means you'll have more silicon tubing acting like a pressure accumulator when the flow is choked (or stopped) using the throttling valve as the tubing bulges under pressure. On our nano-brewery set-ups this probably means bugger all, as we don't need fine control of pressure in the system. In saying that I also don't want undue stress on my silicon hoses and clamps when deadheading the pump, so I keep it close to the pump outlet.

 

[fraser_john]

<snip> pressure in the system <snip>

Maybe, but not sure our little March or diaxon(.sp?) pumps are that capable of generating a lot of pressure given their head lift is pretty nominal (2.5m for the 809 HS). My outlet valve is after 4m of stainless tube through the hex plus about another meter of silicone and never noticed a pressure surge when I let off the valve from the length of silicone tube.

 

[QldKev]

And I need to add, apart from putting a drop of oil in the hole in the pump housing when I first turned it on its side, I dont remember ever oiling it again.
As far as I know it is still pumping away as it should.

I remember reading a post from TescoPumps about the March 809 saying in a homebrew application it should never really need oil. Mines a few years old now and has never received a touch of oil, but after reading / thinking about it I may add a drop.