Weird problem with Sillcock

[Henry]

I recently connected a Melnor Electronic Aqua Timer (Model 3015) to my sillcock and set it to water 10 minutes every 6am.

It worked fine for 2 days. On 3rd day morning (about 6:30am) I found a big stream of water pouring out from the sillcock's handle. This had never happened. I turned off the sillcock right away. After that, no matter how I turned it on or off, I just couldn't reproduce the problem. It just didn't leak even a drop of water.

Thought it was ok, I turned on the sillcock. Everything worked fine for another 2 days. This morning, again, I found water pouring out of the sillcock handle! And same thing, after I turned it off, I couldn't reproduce it. This is weird!

I wonder if this is because the timer's valve causes a quick high pressure when it turns off and the pressure pops up the handle from sillcock? If that's the reason, how come I couldn't manually make it leaking by pulling out the handle a little bit?

Does anyone has similar experience? Thanks!

[trader4]

Is the sill c*ck an anti-siphon one? If the anti-siphon sticks, water will pour out, but the one's I've seen had a seperate plastic cap gizmo on top where the water came out. They are repairable if that's what it is.

Why the auto valve affects it that way, I couldn't say. For one thing, the ones I've seen use a gear drive and the water doesn't go on or off very fast. It could just be that the anti-siphon is fouled up and it's just a coincidence.

[Henry]

It is anti-siphon. But no water coming out from there. Also, if it's a problem with the anti-siphone, it should be reproducible.

[Joseph Meehan]

Maybe, or maybe the packing just can't handle it over long periods. Off hand I would think you are right about it.

[Jeff Wisnia]

Could you better describe what you mean when you say "out from the silcock's handle." I'm having a hard time visualizing what part of a "handle" could have water coming out of it.

Is this a conventional silcock with a knob you rotate several turns ccw to open, or is it some kind of handle operated valve like a gate valve?

Are you trying to say that the water is coming out around a valve stem? And if so, what flow rate does "pouring" mean.

Jeff

[Harry K]

I second that request.

Harry K

[Henry]

It's a conventional sillcock. It has a stem going through the center of the retaining nut and is connected to the handle with a screw. Water was coming out from the gap between the retaining nut and the stem. It looks like the water was spraying out from the handle's smaller end. The rate was about 1/3 gallon/min.

I th>

[Jeff Wisnia]

"Forgetting it" would be unlikely, since even if the plumber removed the cap, handle and stem to prevent frying the seals if he/she was soldering the valve onto the piping, and replaced it when done, there'd be no reason to disassemble things to the point where the stem seal could be lost. If it isn't there, it's more likely some hung over line worker at the factory skipped putting it in.

One thing we didn't cover, Henry; When you open the sillcock to use it with the timer, is it fully opened or do you leave it partially closed to control how far water sprayed from a sprinkler? If partially opened that might have some bearing on the weirdness you've described.

I'm thinking, "check the stem seal", eggsackly like you at this point, Henry. Pull the handle and cap off and see what you've find there, it's gotta be Abby Normal. Maybe the stem seal is made from an elastomer ("rubber") which has developed a crack on one side that somehow opens up and "unseals" every third (charmed) day.

Let us know what you find.

Jeff

[Charlie]

I just had this happen to me last night on my outdoor faucet. It's a 'frost-free' style that has the stem washer back in the wall about 12". When I open the valve it doesn't leak from the packing nut, but from a small hole in the stem itself (???), which is visible when you remove the handle... Did a washer disintegrate?

charlie

[maradcliff]

A sillcock sounds like something that should be included in a gay house !!!! Or is that a sillycock? :)

[Dan Lanciani]

| I just had this happen to me last night on my outdoor faucet. It's a | 'frost-free' style that has the stem washer back in the wall about 12". When | I open the valve it doesn't leak from the packing nut, but from a small | hole in the stem itself (???), which is visible when you remove the | handle...

I have one like this as well. The discharge through the inside of the stem appears to be intentional. At the inside end of the stem is a piston mechanism with a spring that pushes it into the position that opens the path to the stem and blocks the water inlet. (Closing the valve also blocks the inlet and the stem path by compressing the spring.) As long as there is enough pressure at the inlet to drive the piston against the spring and into the stem the stem path is sealed. I'm not sure why the mechanism is built this way. Perhaps they now want the reverse-check function to be referenced to atmospheric pressure plus whatever the spring adds? Or perhaps they want a discharge path for reverse flow so it won't have a chance to work its way through the check valve into the water supply? Does this have anything to do with the reduced pressure zone protector valves for sprinklers that the plumbers now say are better than the old double-check valves? (The latter do not have a discharge but the former do.)

Note that the above-described mechanism is in addition to the anti-siphon (vacuum breaker) device on the outside end of the fixture. Also, it is not an "in-use" drain for the frost-free function since it will not drain the fixture while the valve is off. The "in-use" drain is yet another spring-loaded piston on the bottom of some frost-free fixtures that opens on low pressure regardless of the state of the main valve.

Anyway, it appears that the piston can get stuck so that it does not fully seal the discharge path out through the stem. Usually fully closing the valve correctly repositions the piston, but I'm afraid the little fingers on which it slides can get bent or simply become rough with scale. Since the piston mechanism does not appear to relate to the forst-free function, perhaps the original poster has one in his normal sillcock.

Dan Lanciani ddl@danlan.*com

[Ken Withey]

It is a secondary check valve failure of the cone shaped washer at the seat end of the frost free sillcock. You can order the parts here......

Hope that helps.

Ken W