How cold?

[irritation]

How cold does it need to get to damage an above ground backflow preventer?
I personally have not seen one freeze enough to break until it gets into the lower 20's but I guess it would depend on how long it stayed below freezing.
Just looking for some thoughts. Thanks.

[cush]

exactly 32 degrees just a matter of how long is stays there.

[ccane]

It depends, but if its on the north side of the house and it gets to 32 I'd make sure it's drained, at least the south sides retain some solar heat

[Mjtrole]

How cold does it need to get to damage an above ground backflow preventer?
I personally have not seen one freeze enough to break until it gets into the lower 20's but I guess it would depend on how long it stayed below freezing.
Just looking for some thoughts. Thanks.

temperature has most to do with it but you have to be aware of the wind which can cause the temperature in that spot to drop even more, funny story....everything up here in michigan froze by the second week of november last year, had one lady that went out of town and forgot to call to winterize, went there to start it up and the water was still on in the basement from last season, Nothing was frozen, no copper splits or poly breaks, unreal for the winter we had.