Film-Tech Forum ARCHIVE: How to make auto-sensor faucets drip?

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Posted by Barry Floyd (Member # 385) on 01-06-2015, 03:59 PM:

At the drive-in, we put in brand new touch-less automatic sensor type faucets on all 6 of the sinks in the public restrooms. While our restrooms are heated inside, the actual copper pipe that supplies the sinks is inside the exterior concrete block walls. The block walls are insulated to a degree, but I'm not sure how low of a temperature the pipes will stand. It's getting cold here in the next day or so with temps in the single digits. I typically crack the faucet handles just enough to get a steady drip, but can seem to find a way to do that now.

It's been suggested by other drive-in owners to turn off the water and blow out the pipes with compressed air. The way our water system is designed, I can do that with the hot water pipes, but not with the cold water lines. Typically the pipes that freeze in most buildings are the hot supply lines, but in my case since our building has a backflow preventer on the main supply line coming in the building, the water in the pipes does not move or fluctuate past the point of the backflow preventer.

Any suggestions?

Posted by Martin McCaffery (Member # 37) on 01-06-2015, 04:15 PM:

I presume the sensors are electric. What happens when you kill the electricity to them with the water running?

Posted by Marcel Birgelen (Member # 6801) on 01-06-2015, 04:31 PM:

quote: Martin McCaffery
I presume the sensors are electric. What happens when you kill the electricity to them with the water running?

You really make me wondering what other things those sensors could run on [Wink]

.

Your mileage may vary on your particular models, but at least the ones at the office close the valve automatically once you kill the power. I guess it's some kind of magnetic valve that needs juice applied to open. This kind of design makes a lot of sense so I guess the average automatic faucet will work like this.

I've been pondering about any other options, but I guess the "not dripping" thing is part of their list of features [Wink]

. Maybe someone knows of a reliable way of triggering them remotely every few hours or so?

Posted by Frank Cox (Member # 6258) on 01-06-2015, 04:44 PM:

I have personally never needed to use it, but folks who have water lines in exposed locations around here (like water hookups to trailers and whatnot) use electric pipe heating cables to prevent the lines from freezing.

Here is one example of pipe heating cable. It's the first one that came up on a google search.

Posted by Chris Daigle (Member # 7347) on 01-06-2015, 05:02 PM:

I assume you have a shut-off valve below each sink for both the hot and cold water....so just turn off the water, disconnect the hoses that are feeding the automatic faucets and either connect them to a piece of garden hose with an adjustable nozzle on the end and run that back up to the sink to drain. Or, you don't need the nozzle if you just crack the shutoff valve a little to have a small amount of water coming out of the hose.

Posted by Marcel Birgelen (Member # 6801) on 01-06-2015, 05:28 PM:

quote: Frank Cox
I have personally never needed to use it, but folks who have water lines in exposed locations around here (like water hookups to trailers and whatnot) use electric pipe heating cables to prevent the lines from freezing.

Those things probably work great, but how do you wrap them around a pipe inside a concrete wall? [Smile]

Posted by Gordon McLeod (Member # 33) on 01-06-2015, 09:51 PM:

The other idea is to install professionally cathodic heater in the pipes

Posted by Joe Redifer (Member # 3) on 01-06-2015, 10:50 PM:

As long as your copper pipes aren't ancient, they can handle single digit temperatures especially only for a night or two. When it gets colder than that is when you need to worry.

Posted by Barry Floyd (Member # 385) on 01-07-2015, 09:10 AM:

Like Chris mentioned above, I'm thinking about un-screwing the flexible lines that go to the electric valves and using some vinyl tubing to route the dripping water from the shut off valves to the floor drains in the restrooms. Won't be pretty, but we're closed until March anyway so it won't really matter what it looks like.

Posted by Jim Cassedy (Member # 4115) on 01-07-2015, 10:59 AM:

Is there somewhere, at the lowest point in the line, you could install
a drain-cock? My folks used to have a summer home and every year when
shutting the place up for the winter we'd turn off the main water supply,
open one or more sink faucets,(to relieve any vacuum), put a bucket
under the drain-cock, open the valve and let gravity do the rest.
The the cock-valve & sink & tub taps would stay open for the winter.

The drain-thingy in my folks' house was just past the main shut off valve
where the water main came in from the street, so it pretty much drained
all the pipes. Don't know if you could do something similar at your place.

Posted by Barry Floyd (Member # 385) on 01-07-2015, 11:40 AM:

We typically keep the water turned on during the winter months for cleaning and such. The way the water supply system is laid out in the building, there's really not a way to isolate the restrooms from the rest of the building. The restrooms do have their own individual water heaters, so draining the hot water lines wouldn't be too much of an issue. I have no way of purging the cold water lines without cutting off the water to the entire building.

Posted by Dave Bird (Member # 490) on 01-07-2015, 12:25 PM:

As a guy who's winterized cottages/drive-in for many years now, your quick and dirty" bypass to temporary tap solution should work. We of course blow our lines each fall (almost minus 40 today at our drive-in), but like you, we installed auto-taps this year and completely replaced our sewer lines. This meant pipes in the floor again, so I really hope the plumbers blew the lines out well as I wasn't able to do it this year. Another thing you could try is putting a shut-off valve to the lines before they enter the wall with a drain valve just AFTER it. Then shut the sink supply off and blow out just that part of the line. Happy New Year!

Posted by Jim Bedford (Member # 4) on 01-08-2015, 11:34 AM:

Heat tape. It's thermostatically controlled so would only come on if the temp drops to 32°. No need to do anything heroic.

Posted by Barry Floyd (Member # 385) on 01-12-2015, 09:59 AM:

Thanks for all of the replies. I was way over-thinking it and settled upon a combination of Jim's "Heat Tape" and a little extra heat turned up inside the restrooms. Since the pipes are all copper and they are all connected to each other inside the walls, the heat from the tape conducted all the way back into the wall.