The American Standard Tub/Shower valves installed at Brava are known to have a flaw. American Standard has replaced these valves at Brava, under warranty, as recently as May 2013.
What’s the problem with these valves?
All single lever valves have an internal part, known as a Pressure Balancing Unit, that is designed to compensate for hot and cold water pressure differences. This unit is the part that fails in the valves we have. While chatting with some plumbers I was told that the Pressure Balancing Unit has a spool that should shift side to side depending on pressure differences in the hot and cold water. This spool apparently gets sticky and move slowly or in jerks and thus affects water temperature leaving the valve.
I found this bit of text on the Net explaining what they do:
“A pressure balance valve is a sophisticated plumbing device that reacts to changes in the pressure of the delivery water. Typically, both hot and cold water sources are fed into the valve, and its job is to ensure that the volume of water that leaves it is a constant mix of these two sources, even if the delivery pressure of the two sources changes. This is very important to keep the temperature of a shower constant even when the supply is not.”
How can this affect you?
When the valve issue is minor, let say a sticky spool that moves slowly, the initial symptoms you may notice is difficulty in setting a constant temperature while showering.
The water pressure supplied to your unit changes constantly as other residents turn taps on and off. The Pressure Balancing Unit in the shower valve is supposed to compensate for these minor changes in pressure.
When the valve fails completely, as in a stuck spool, it will allow the hot and cold water sides to come in contact. When this happens water will flow from the higher pressure side of the valve to the lower pressure side. For example, if the cold water pressure is 2 psi higher than the hot water pressure, the cold water will push the hot water backwards in the pipe eventually filling all the hot water pipes of the unit with cold water.
If this goes on for extended periods of time, say overnight, the cold water will fill all the hot water pipes of that unit and then start filling the hot water pipes that supply other units.
At this point, if you were to turn on the hot tap you would get only cold water. Running the hot tap would eventually use up the cold water in the pipes and provide hot water. However, if you are the first to use hot water in the morning it could take 10 minutes or more to flush all the cold water from the pipes.
The opposite would happen if the hot water pressure were 2psi higher than the cold water pressure giving you hot water from the cold tap.
All building water pressures are set so that the cold water pressure is slightly higher than the hot water pressure. This is done for safety as a failed valve would produce cooler water than expected rather than warmer or hotter.
How can I check to see if it’s one of my valves causing the issue?
The following tests only work for valves that have completely failed where the spool is stuck and bypassing water from one side to the other in the off position. They don’t work to find a valve which is simply making it difficult to set your water temperature while showering.
While not definitive, the easiest way I’ve found to check for failure is to put an ear to your tub/shower valve while it is turned OFF. If you hear any noise in the valve, like a hissing, it has likely failed and you should contact the building manager via email at firstname.lastname@example.org.
Make sure that your first water use, after you get up in the morning or after an extended time without water use, is to turn on your shower to the cold position. If you get hot water immediately turn off the water. The water being hot immediately tells us that your cold water pipe, at that fixture, is full of hot water. Now go to your second shower valve, if you have one, and do the same test by turning on the cold water. Unless that valve has failed as well you’ll likely have some delay in getting hot water.
If you have this condition please contact the manager via email at email@example.com.
The most definitive way to determine if your tub/shower valves are causing this issue is to check the temperature of your cold water pipe where it enters your unit after 4-6 hours of no water use.
Here’s the theory:
The hot and cold water supply pipes enter your unit at one location. At this location there are shut-off valves for both the hot and cold water. These shut-off valves turn off the water to your entire unit. After the shut-off valves the pipes split off to feed all your fixtures. i.e. Sinks, Tubs, Toilet…
The shut-off valves are normally located in your front hall closet or in your storage room. They will be behind a 10″ square metal panel mounted about 18? above the floor. You will need a screwdriver to remove the panel.
The Blue valve is for the Cold and the Red is for the Hot. They may not be readily visible just by looking behind the panel. Sometimes they are mounted above, below, left or right of the hole. It may take some effort to get to them.
Once you’ve located them I would suggest that you run the hot and cold water, at any sink, until they are fully hot and cold.
Then return to the shut-off valves and gingerly touch the pipes in the wall right where the shut-off valves are. The Red valve pipe will be VERY hot and the Blue valve pipe will be cold. Be careful not to burn yourself on the hot pipe.
It stands to reason that if all the fixtures in your unit are turned OFF then no water should be flowing through these shut-off valves.
It also stands to reason that if you don’t use any water in your unit, for a 4 hour or longer period, the hot and cold pipes at this location should both eventually be the same temperature. This is due to the hot pipe cooling down to room temp and the cold water pipe warming up to room temp. Makes sense eh?
So, if after 4 hours, or more, of no water use you find that the hot and cold pipes are both hot or both very cold there must have been some water flow through the unit. If this is the case then it’s likely that your tub/shower valve is bypassing water.
It might be best to check the temperature of these pipes right after getting up or right after getting home from work. Make sure not to run any water in the unit before checking the temperatures.
If you find that you have an issue please contact the Resident Manager via email at firstname.lastname@example.org.
What is the fix for a failed valve?
The fix is as easy as replacing the Pressure Balancing Unit in the valve housing. These Pressure Balancing Units cost under $20 and it takes a plumber under 20 minutes to change it out.