Can ball valves be serviced? How well do they hold up?

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Old 03-28-13, 07:32 PM
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Can ball valves be serviced? How well do they hold up?

Do ball valves ever get "loose" or leak out the stem like globe valves? Doesn't look like there's any "adjustment" like the packing around a globe valve stem. I was taught a gate valve is the highest quality, least wear, longest lasting but here I see ball valves recommended most often.
 
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Old 03-28-13, 07:43 PM
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ball valve

Some ball valves do have a "packing nut" that can be tightened, but many don't. Ball valves are good for on / off, and the valve position can be seen at a glance. For throttling flow they're not so good, and continued use at very low flows can cause erosion of the ball inside. Globe valves are the best for throttling flow. Steve
 
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Old 03-28-13, 07:49 PM
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Gate valves have their place, but they have their own set of problems.

1. They usually will not provide 100% shutoff. Sometimes you don't need it, but when you do, you do.

2. When you 'crank' them down in an attempt to stop them from leaking, the gate gets wedged into the slot and when you go to open them again the stem actually breaks out of the top of the gate and then yer scr3w3d cuz you can't open the valve again.

3. They are just as prone to stem leaks as any other valve.

4. Not very good for throttling apps.

5. Pretty good Cv rating.


Pros (more than) and cons of ball valves.

1. Ball valves are pretty durable and will provide positive 100% shutoff.

2. Not very good for throttling apps.

3. They can develop stem leaks. There IS a packing gland nut on better quality valves. I have seen some el-cheapo ones that don't.

4. Full port ball valves have very high Cv rating.


As a 'service valve' I would always install a full port ball valve. They can sit in a line unused for decade and when closed will actually do so, 100%.

Honestly, I can't think of a reason to install a gate valve... I'd like to hear some if anyone has any.
 
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Old 03-28-13, 08:00 PM
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As Steve said, ball valves are good for 100% open or shut - at those positions, there should not be pressure on the stem packing. Like other valves, they should be exercised periodically.

Gate valves have their own problems and have been largely replaced by ball valves for residential hydronic heating.
 
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Old 03-28-13, 08:44 PM
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In addition to Trooper's pros and cons, ball valves have another advantage over gate valves (and globe valves, too) for isolation service: just one-quarter turn between full open and full shut. Gates require multiple turns of the handwheel - and the torque to operate the handwheel can be rather high if the packing nut is tight or if the wedge is stuck in the seats.

Also, to keep pressure off the stem packing when fully open, both gates and globes must be on their backseats. With a ball valve, assuming the ball seals are intact, pressure shouldn't ever be on the stem packing.

But, back to the original question: can ball valves be "serviced?" If the ball or its seals become worn and leaky, I would replace the whole valve.
 
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Old 03-29-13, 09:20 PM
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Ball stands up to 180 heat OK?
 
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Old 03-30-13, 08:29 AM
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Many ball valves use PTFE (Teflon) - good for 450 deg F. But check the manufacturer's specs for whatever valve you are wondering about.

Ball valves have been used successfully for hydronic heating systems for many years. You are not plowing new ground.
 
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Old 03-30-13, 09:09 AM
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I think I would tend to shy away from any of the el-cheapo BVs you might find at the big box stores.
 
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Old 03-30-13, 10:16 AM
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My local Ace hardware stocks Mueller B&K brass ball valves. I have also had good experience with Apollo ball valves.
 
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Old 03-30-13, 07:12 PM
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I've used ball valves as king valves in a residential steam system and they hold up quite well to the temperature. Although in the future i may switch to gates.
 
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Old 03-30-13, 07:19 PM
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Although in the future i may switch to gates.
Why?
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Old 03-30-13, 08:33 PM
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Tad cheaper plus i think gate valves look a bit better in a steam application then a ball valve.
 
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Old 03-31-13, 05:28 AM
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ball valves

I've had good luck with Apollo too-
Steve
 
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