Draining a back flow - question

[lilscorpion]

I’ve been winterizing systems for years both my personal home and professionally when I was younger. By now I thought I knew the steps by heart. One step that I’ve never done is rotate the valves on either side of the back flow to 45*...like never. I’ve always left them open, as well as the test valves, after completely draining and blowing out the entire system with my air compressor. I know you shouldn’t leave them fully closed because there can be water trapped in the ball which can freeze...but “the pros” say 45*, not fully open. Anyone know why partially open is more desirable than fully open? My brain says there’s no difference given how a ball valve is designed.

TIA

 

[Kaizen]

I think it’s so if it does freeze or jam you can work it free going both ways


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[burleyfarm]

I leave all mine at 45 degrees because that’s what I was taught. I don’t know why but this seems to be quite common.


Dave

 

[yeldogt]

have never heard of that .... so mine are full open.

maybe years ago the first one stuck full open .....?

 

[2gslse]

The reason is when you operated the valve there can be water inside the ball that is now trapped and will freeze therefore breaking the valve.we had multiple valves at work freeze under the cooling towers this way until we started leaving them positioned to drain pipes and valve

 

[king nero]

I was told so if you encounter a stuck valve, and you can not see or determine it's position, you cannot turn the handle the "wrong" way because either way it should work free.

If you leave a valve at a fully open/close position and you want to work it free, you have a 50% chance you are trying to turn it the wrong way...

 

[lilscorpion]

The reason is when you operated the valve there can be water inside the ball that is now trapped and will freeze therefore breaking the valve.we had multiple valves at work freeze under the cooling towers this way until we started leaving them positioned to drain pipes and valve

Yeah that’s what I was taught too but full open is a drain position that can’t have water trapped.

 

[lilscorpion]

Years ago, I replaced two outdoor bibs with ball valves. When I left both full open after draining, they both cracked when residual water froze. After I replaced them, I've never had a problem leaving them open 45 degrees.

Yeah, so money cracked this year for the first time in 30-something years while in the full open position...guess it’s 45 now for me too.

 

[lilscorpion]

I was told so if you encounter a stuck valve, and you can not see or determine it's position, you cannot turn the handle the "wrong" way because either way it should work free.

If you leave a valve at a fully open/close position and you want to work it free, you have a 50% chance you are trying to turn it the wrong way...

Ok, this makes sense except you can usually see the cast position stops on the handle I rarely try to force it the wrong way. That being said, if the valve was in a location difficult to get to, it makes perfect sense.

 

[king nero]

I was working at the time in a factory with piping with large, round (steering-wheel like) handles with no indication of their position, so there it made sense. I know on the single-bar handles, they indicate the valve position, so there it is not applicable.

 

[fitter30]

I’ve been winterizing systems for years both my personal home and professionally when I was younger. By now I thought I knew the steps by heart. One step that I’ve never done is rotate the valves on either side of the back flow to 45*...like never. I’ve always left them open, as well as the test valves, after completely draining and blowing out the entire system with my air compressor. I know you shouldn’t leave them fully closed because there can be water trapped in the ball which can freeze...but “the pros” say 45*, not fully open. Anyone know why partially open is more desirable than fully open? My brain says there’s no difference given how a ball valve is designed.

TIA

For what backflows cost and their rebuilt parts i personality would pull it and put in a nice warm spot where it wouldn't get lonely


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