Gravity feeding through a plate or counterflow chiller?

What kind of height delta do you need to effectively gravity feed through a plate or counterflow chiller? A friend of mine always pumps through his, but I've seen a few setups around here that definitely appear to be gravity fed instead. And since gravity's free, it fits my budget a whole lot better than does a pump and all the requisite fittings...

 

I gravity feed through my plate chiller with the kettle about a foot above the chiller inlet, then with the carboy about 2 feet below the outlet. So...a foot. Gravity is gravity, and water is water, if it can go down, it will.

 

I gravity feed through my counterflow chiller and it takes about 10-13 minutes to chill 5.5 gallons. I don't even have a bulkhead on my brew kettle, I have the copper inlet going up and over the top of the kettle, then down to the bottom. Works same as a siphon. Height difference between kettle and carboy is maybe 3 feet.

 

Thanks folks, sounds easy enough...

Now for my next question: how best do you go about sanitizing such a device, without a pump? My buddy always pumps boiling wort through his for a few minutes, but that'd obviously not be an option, sans pump...

 

I used to use my mlt outlet to gravity feed some sanitizer through the chiller. I pump now.

 

When I gravity fed mine I would put around a quart of sanitizer through the inlet tube and let it soak in there until I was ready to chill.

 

I gravity flow about a gallon worth of boiling wort through and add the gallon back to the boil with 5 minutes to go.

 

I have a shut off valve at the outlet of my CFC... so I run some Star-San through the chiller, then shut it off at the outlet until I'm ready to run the beer through. When it's time to chill the beer... I run it through the system, and when I start seeing beer instead of sanitizer coming though, I shut the valve, drain the Star-San from the carboy, give everything a sanitizer spritz... then open the valve and let the beer run on into the fermenter.

 

If you're inclined to do the math & calculate pressure, every foot of height delta gives you .433 PSI (so 2.3 ft for 1 PSI).