Low water flow in anti frost outdoor faucet (2024)

Hi all,

I'm new to this forum which I found by looking for solution for the same problem I have.
Our outdoor anti frost faucet has very low pressure. I turned off the shut off valve, opened and took some photos - see below.

Any advice?
Thanks in advance.

ps edit - with some gentle force I've unscrewed the white plastic cap. It was tight, probably since last year when the o-ring erroded, I replaced it with whatever was available in store - which was I think a thicker o-ring. So now it's held tight. I fully opened it, then opened the shut-off valve, and still it's a low flow of water.

That cap is anti siphon device and has nothing to do with water flow. With the water shut off, remove the handle then the stem. It will be about 10" long. At the end there will be a washer that closes off the water flow. Replace that and before replacing the stem, turn on the water to flush out any debris.

Thank you guys for the helpful answers. I opened the faucet and indeed without it there's a much stronger flow; i didn't measure it in GPM but it's at least twice stronger. I opened-closed the shut-off to full power, trying to release something that might be stuck there. Washed the inner part of the spigot. And still when re-connected it all, the flow is still slow.
I repeated it all again, no change. Attaching a photo of the inner parts.
Any advise? they seem fine to my un-experienced eye...

Maybe put an appropriate diameter flex tube/hose on the open end of the plumbing, using a hose clamp to secure it. Turn on the water. Two things... is the flow from that much bigger that way, and does debris maybe get washed out?

If you fill a 5-gallon bucket, the gpm is 300 divided by (the number of seconds it takes to fill the bucket).

seiyafan said:

if you look at the cutaway view, anti-frost faucet is like a pipe within a pipe, so the flow will be restricted. If you can install a ball valve you can replace it with a regular faucet.

Click to expand...

You appear to not understand the frost free faucet purpose and construction.

If you think the flow is still too low with the stem removed, may have to look further back. BTW, the O rings look a little dry. Replace them or a little silicone grease will help.

If you want to get a replacements parts.
https://terrylove.com/forums/index.php?threads/mueller-sillco*ck.58092/

Roi said:

Do you think the little-dry O ring can affect the flow that much?

Click to expand...

No way.

Is that a set screw about 15% along the blue line, starting on he left side of the line? I am trying to figure out how water gets by that seal that is about 30% along the blue line. It must go inside by the spring.

You might take these numbers to the maker, and ask what they think.

Thanks.
That is a screw - I attach a photo from the other side.

ok. I soaked the "moving part" in a cleaning solution (didn't have descaling, which i wanted, in case there's mineral built inside; used degreaser). washed, blew strongly. applied silicone. resealed with teflon all connection points.
Now I get to fill a 5gal in 2:45 instead of 4+ mins... which is approx 2gpm. better than 1.2 (before), worse then 6.8 (without the spigot).

Do these numbers make more sense for such a system?

Thanks again for you all being such a helpful resource!

Roi said:

Do these numbers make more sense for such a system?

Click to expand...

I think you have identified your problem and lead to a cure.

Soak it in vinegar a long time, I would say. Maybe agitated periodically. Petroleum is not good for rubber.

If removing that screw let you take the assembly apart, you could clean mechanically.