Replies

1. 
   xxPaulCPxx | Jul 28, 2010 01:31pm | #1

   ...and THAT"S why you should

   ...and THAT"S why you should only use full flow ball valves.

1. 
   rdesigns | Jul 28, 2010 04:36pm | #2

   Right. And even gate valves made in the usa have always been notorious for leaking slightly.

2. 
   plumber_bob | Jul 28, 2010 08:42pm | #3

   Both Paulcp, and rdisigns are right on the mark with their comments, have you tried to tighten the packing nuts?

   I've seen loose packing nuts on many valves straight outta the box.

3. 
   DanH | Jul 28, 2010 08:46pm | #4

   Gate valves are designed to leak.  Especialy when installed handle-up.

1. 
   Tim | Jul 29, 2010 11:22am | #7

   I wouldn't say

   they were designed to leak.

   But I fully agree they are not the best choice for plumbing shut-offs. In appropriate applications, gate valves work quite well. Ever see a 10" ball valve?

4. 
   DaveRicheson | Jul 29, 2010 06:27am | #5

   Are you sure you have gate valves?

   Gates is a valve manufacturer and the term gate refers to a type of valve, so buying a Gates valve does not necessarily mean you have a gate valve.

   http://en.wikipedia.org/wiki/Gate_valve

   If your valves have  seats and washers in them, they are not gate valves, but the more common globe type.

1. 
   DanH | Jul 29, 2010 07:27am | #6

   The way we know he has gate valves is that they leak.  In a gate valve a wedge-shaped gate is pushed down between two seats.  When it wedges fully then it presses tightly against the seats and the flow is stopped.  But sediment builds up in the area between the seats, preventing the gate from descending fully and sealing.  Hence the leaks.

   Globe and ball valves are self-cleaning, but not gate valves.

1. 
   DaveRicheson | Jul 29, 2010 03:44pm | #8

   Some are wedge shaped and some are striaght gates. I,ve got  between 50 and 100 in this facility. Some will leak through, some shut off completely. same for globe valves with seats and washers. I"ve learned not to be to catagorical of products just because I may have experienced problems with a few. 

2. 
   Scott | Jul 29, 2010 11:58pm | #10

   >>>The way we know he has

   >>>The way we know he has gate valves is that they leak.

   That's my experience too. I've always wondered why they were made, what their proper useage was (if there is such a thing), and why they survive in the marketplace.

1. 
   DanH | Jul 30, 2010 08:24am | #12

   Gate valves are fine as "normally closed" valves (and in extreme conditions ball valves can have problems with that duty, due to corrosion/mineral buildup on the ball).

5. 
   rdesigns | Jul 29, 2010 05:06pm | #9

   In an effort to be a little more helpful:

   Try having the water water running thru the gate valve as you are turning it off--this way, the continued flow will help flush out debris that tends to settle in the cradle, debris that can prevent the gate from seating fully.

   No guarantee, but it sometimes helps.

6. 
   Hudson Valley Carpenter | Jul 30, 2010 04:00am | #11

   Hard Water, mineral deposits

   I've replaced a number of brass gate valves when they failed to close completely.  In each case I found mineral deposits on the wedge, stuff that was practically welded to the surface.  So if you live in a hard water area you should expect that any brass gate valve which stays open nearly all the time will collect mineral deposits which will make it impossible to close completely.  Best remedy, as previously noted, is to replumb with ball valves.   They're much easier to operate and mineral won't adhere to the chrome plated ball. 

7. 
   daveyg | Aug 01, 2010 01:19am | #13

   Maybe it's the hardwater and not the Chinese manufacturers ;-)   I'd never had the problem living in the city.  The valves were made in the USA and the water was clean.  Two variables: water quality and valve quality.  I suppose the truth will only be found by removing the leaky valve and inspecting for minerals.  Or...buying a brand new gate valve and testing for leaks.

   Since I now have to deal with hard water, it seems that I should replace gate valves with something that has replaceable seats.  I've broken a few plastic ball valve stems because minerals had cemented the valves open.  The brass versions are better but still get crusty.  Globe valves?

   Thanks for all your responses,

   Dave

1. 
   DanH | Aug 01, 2010 11:20am | #14

   The main disadvantage of globe valves is that they aren't full flow.  The seats can erode over time, but usually only if the water's corrosive or the valves get a lot of use.  They do occasionally leak and refuse to shut off (such as the 34 year old shutoff valve for our toilet), but are far better than gate valves in this regard.

   Best water valve I know of is the shutoff valve the city water folks installed in our house.  It's a cylinder valve (in at the bottom, out at the side) that functions a bit like a ball valve -- still moves easily and smoothly and shuts off completely after 34 years.