Evaporative Water Coolers - Recommendations for roof mounted water supply?

I'm installing a swamp cooler on my flat roof and I want to feed water to it from a 1/2" line inside the house. My question is: how should I set up the roof mounted water supply valve?

I had a look at a friend's cooler and they just had the 1/2" copper pipe sticking out a few inches above the roof with a standard multiturn stop valve (such as you'd find under a sink) on top of that, with the 1/4" swamp cooler feed running from that.

My concern with that design was that the stop valve is out in the open in freezing conditions, and I was worried that the pipe might freeze. OK, so it's only a few inches sticking out above the roof, and maybe it'll never freeze because of convection flow in the pipe, but to be on the safe side, I decided to instead use a frost free garden faucet sticking up vertically through the roof instead. That way, the water is shut off safely down below the roof.

However, a contractor recently advised me against that, saying that the frost free faucets are designed to work in a horizontal mounting, not vertical as I had planned.

So, what's the standard way to do this in freezing climates? I live in Santa Fe, NM, so night temperatures get down to a little below zero on occasion, but not often.

Any advice much appreciated.

Simon

Id put a shut off on the water line inside the home with a drain down in it. The shut off on the roof also so you can work on the unit faster.

Hi, I live in socal my cooler goes through the wall. when you shut down your cooler for winter shut off the water and drain the line. open the line from the shut off valve and the float on the cooler. if you can use a air conpressor to drain your line or a tire inflater. idid not drain my line last year and it split a hole in the line. i have seen a lot of mobile homes with coolers on the roof and the line goes from the cooler to hot water vent to the cold water with a saddle valve. i hope this helps.

I realize that I have to disconnect the 1/4" line to the swamp cooler when winterizing. My question is more to do where I should put the stop valve. If the valve is accessible from the roof, then presumably there's a little piece of pipe sticking up through the roof (ending in the stop valve) that has water in it. My thinking was that this might freeze and cause problems.

I've heard of the approach of feeding a 1/4" copper line up through the hot water heater vent, but it just sounds a little cheap somehow... Fine for a retrofit on a mobile home, but what do builders do when they're installing swamp coolers on new home construction?

Ed seems to suggest having two valves - one on the roof and one in the house with a drain so that you can clear the water out of the pipe going to the roof valve (if I understand correctly). That sounds solid, but perhaps overkill - plus I would have to find a place for the drain. Do people actually routinely use this setup?

Right now, my thinking is that perhaps that little stub of 1/2" copper pipe sticking up through the roof with a stop valve on it isn't really a problem - particularly if I insulate the pipe well and cover it with a polystyrene faucet cover in winter. Conduction and convection from inside the house should probably keep it mostly unfrozen, and if it freezes a little at the end, probably not a big deal. This seems to be the setup at a friend's newly built house. Or is this a crazy idea?

Cheers,

Sy