vacuum breaker and flexible/removable plumping

2 seperate questions 1) I'm trying to think of a good reason why I need a vacuum breaker in the hot water line to my darkroom sink. I don't want hot water entering my cold water system so I always put one there, but a little bit of cold water entering my hot really doesnt seem a big issue. My darkroom lines are quite long (30 feet?) and I shut off the darkroom lines when I'm not using them so I see the risk of hot water entering the house loop as pretty minimal and inconsequential. Comments? Yes I know they are cheap but they also can be sources of leaks, and in my experience usually are. And cheap is too expensive right now.

2) I'm also interested to know if/how other people have rigged up flexible plumbing to their work area. I used garden hose for years and it worked fine, but it just isn't working anymore. Leaks, leaks, leaks, and I'm sick of trying to make it work. I need to be able to move my sink, (which is on rollers) at least a few feet, and (less importantly) I'd like to be able to remove and reattach the plumbing from the sink easily so I can move it even further on occasion. I'm thinking of using pex because I have about 1/3 of the total length I'd need to do the job. But the last requirement is, I have to me able to do this on the real cheap, I dont have more than $50-75 to spend on it.

For flexible hose, how about washing machine hose? Even the steel braided ones aren't terribly expensive.

I don't think you need a vacuum breaker at all, unless you have a hose attached to the outlet of the faucet which could draw contaminated water back into your lines in the event of a loss of water pressure. If the only potential source of cross connection is inside the faucet itself you don't need a vacuum breaker, just as you don't anywhere else.

To remove the plumbing easily I think mounting it all on a piece of metal or exterior plywood, then holding it onto the sink with a c-clamp would work. You might need to cut some clearance on the back of the sink for the lines.

Me thinks what you are asking about is a "back flow preventer" not a vacuum breaker. You place a vacuum breaker on the waste line, eg:between a dishwasher drain line and the sink drain to prevent the DW from getting waste water back when its finished and you run water in the sink. A back flow preventer is installed in supply lines to prevent siphoning water back into the cullinary supply.

lxdude said:

For flexible hose, how about washing machine hose? Even the steel braided ones aren't terribly expensive.

I don't think you need a vacuum breaker at all, unless you have a hose attached to the outlet of the faucet which could draw contaminated water back into your lines in the event of a loss of water pressure. If the only potential source of cross connection is inside the faucet itself you don't need a vacuum breaker, just as you don't anywhere else.

To remove the plumbing easily I think mounting it all on a piece of metal or exterior plywood, then holding it onto the sink with a c-clamp would work. You might need to cut some clearance on the back of the sink for the lines.

Click to expand...

hehe...I could go downstairs while prints are washing, and accidentally get a glass of hot water to drink from the cold water tap. I'm just dumb enough that I might not notice till its too late...

I'm not familiar with the steel hose you are talking about, but I can get 100 feet of pex for $25, plus (I now know) quick release fittings. I should be able to get by with just a T and shut off valve at the start of each line, and a quick release at the sink.

Perhaps I'm wrong on the terminology but dont vacuum breakers and backflow preventers do the same thing? I have a vacuum breaker on my print washer to prevent back flow if the house suddenly calls for water.


I dunno, I'm not even close to being a plumber.

The hot and cold both come from the same source, the line coming into the house, so there should be no way for hot water to flow into the cold water lines; they gain or lose pressure pretty much equally. You will not get flow one into the other unless they are hooked right together, like through a faucet, and even then it's not likely. Think of a kitchen faucet mixing hot and cold. Even if there is a draw elsewhere, positive pressure still exists at the faucet, so no significant crossover occurs. No preventer is needed, or desired.

The vacuum breaker is one form of backflow preventer. It's cheap and reliable. Where there is no backflow preventer, codes require an air gap. For instance, the mouth of a sink faucet is above the rim of the sink so there is always a gap between it and any liquid in the sink. If pressure is lost, there is no way for the liquid in the sink to flow back through the faucet.

The breaker on your print washer should suffice, unless there is some other place, like a short hose attached to the faucet, which could draw liquid in the sink back through your faucet. If you do have a hose on your faucet, a vacuum breaker attached to the faucet mouth will do. Otherwise, a backflow preventer on both hot and cold lines to the sink will be needed. A simple inline vacuum breaker is not suitable for that situation and alternatives are much more costly.

Washing machine hoses are quite sturdy, as they have to hold pressure constantly. Ones with a braided stainless steel or plated steel outer covering are stronger and longer lasting, as the covering reinforces the hose and also protects it from abrasion. It prevents the hose from expanding much at all, and the resultant lack of large expansion and contraction cycles lengthens its life.
The plain black rubber washing machine hose will suffice, but will not last as long. They are fairly inexpensive. Either type is within your budget in the length you apparently need.

The place where it could potentially mix is at my homemade mixer. Seems to me that if I open a cold watr tap in another part of the house, the hot water already running under pressure at the mixer could just go straight down the cold water line and down to the cold water tap I've opened. I dont know how likely it is, and its isnt a terribly bad thing if I plumb the darkroom with something rated for drinking water and don't accidentally drink hot water. But generally washer hose, and most garden hoses, are not rated for drinking water.

I'm heading into town to look at pex stuff tonite, but I'll look at the washer hose too for the hot water line. But I think I might even save money by returning all the hose fittings, adapters and such that I tried to use in exchange for pex.

If water is flowing out from the mixer that will not happen. The path of least resistance is out to atmosphere. What you're talking about doesn't really happen.

EDIT:
To clarify, I'm referring to hot water flowing into cold lines through the mixer.
Curt is absolutely right in his post below about needing one at the mixer outlet (as I also mentioned but didn't emphasize) if there is a chance of contamination. It's a good idea regardless, just in case you might need to hook up a hose. As the print washer already has a vacuum breaker, it should be connected by itself via a T-fitting or Y-adapter.

He's right about ground fault protection, too.

Wayne said:

why I need a vacuum breaker in the hot water line to my darkroom sink.

Click to expand...

What? These only go after the faucet valve. No wonder it leaks (Or do you have separate Hot and Cold faucets?)


Pex is probably OK if you have main shutoff valves to all the tubing just for piece of mind. If you can solder, copper is a lot cheaper and tried and true.

In this picture of a mixing valve, the part on top is the vacuum breaker. It's the last mechanical part on the valve followed by the spout and hose. If for example you should leave a hose in a tank with a solution and there is a drop in water pressure from another fixture on the same line or there is a break in main line that causes a back flow, without the vacuum breaker the solution could back up in the line and when another fixture is turned on the solution could come out. If that fixture is the kitchen sink and you draw a glass of water and drink it.... well you get the idea. You want to have a vacuum breaker on any line that can potentially be in contact with a contaminate that could be drawn into that line. I have one on my garden valve that the hose is attached to. That way if the hose is on the ground or in a bucket of soap and water while washing the car and there is a back suction the soap and water won't end up in the main water line and contaminate other fixtures.

http://www.lawlervalve.com/index.php?p=product&id=27&parent=5


The other piece of safety equipment that shouldn't be over looked is the GFI or GFIC. Should you be at the sink and reach up and turn on a safelight or plug in a timer or other piece of equipment it prevents you from a shock if there is faulty wiring or ground. There are two types, the first is the one that is placed at the beginning of a circuit or at the point were water or hazards might be in place. The second is a circuit breaker that goes into the panel. It's a circuit breaker and GFI in one. Also note the code for the distance of an outlet to a water source. There is a minimum requirement like 5 feet. In the case of a baseboard heater the outlet must not be closer than 6 inches and never over the top of the heater.

It's that time of year also when people use space heaters in small spaces so watch them so they don't get hot at the plug in end that goes into the outlet. The cheap ones get very hot and can flame up and cause a fire or shock. Never use a kerosene heater in an enclosed space it's the wrong application. I know this is more than you ask for but maybe someone will read this and consider the potential hazards.

Good luck,
Curt

Thanks for the education and suggestions. I guess I dont need the breaker(s), esp with pex. I had read on several sites around the web that you should have them on both lines, though I never did before. This is an existing darkroom I just haven't had it hooked up in 3-4 years, and wanted to do it better this time. I do have the vacuum breaker on the spigot leading to my print washer. Nothing else will be in touch with contaminants. I installed GFIC years ago in the darkroom.

I bought 100' of pex tonight (may need to buy 25' more, about $7) and with the quick mount fittings it should take about 10 minutes to install tomorrow. Cost about $65.

Could consider using a PVC check valve instead of an actual vacuum breaker, vacuum breaker on that is a little overkill.