What factors might affect the style of flush valves in your facility? Do you have Diaphragm or Piston Valves? Plumbing engineers may struggle to specify which flush valve to use.
This can be an arduous decision because you will have to stick with one or the other in the long run.
That’s why it is integral to understand the differences and applications from the get-go. Diaphragm flush valves are good for most commercial applications, but in certain scenarios using piston flush valves is a better choice.
History:
Because Sloan manufactures and sells more flushometers for restrooms than any other company and has set the standard in commercial restrooms, it makes sense to reference their technology.
Let’s take a minute to understand why the diaphragm and pistons were created in the first place.
To start, Sloan invented the diaphragm flush valve with the purpose to replace overhead tanks that relied on gravity, not water pressure. Which then reduces water and energy usage.
And then came the piston flush valve. The piston flush valve was invented to withstand hard water that operates under low pressure.
As you can see, the functionality of these types of flush valves is very similar. They both utilize incoming water pressure to flush a commercial urinal or toilet, as opposed to using a gravity tank.
The best part is that they both create a more cost-efficient flush than previous options.
“Many modern commercial toilets use a flushometer instead of a standard flush valve. Because flush valves rely on pressure and flow, they can reset faster than gravity tanks,” according to Corrosionpedia.com.
Technology:
Now here is when it gets interesting.
Even though the theory of operation is fundamentally the same, the main difference between the two is when it comes to their technology.
The diaphragm flush valves regulate pressure inside the valve using a flexible rubber disc or diaphragm that seals the valve seat after each flush. When you move the handle of the flush valve that will cause pressure relief, which will then cause the diaphragm to flex up and release water into the urinal or toilet.
Piston flush valves regulate pressure inside the valve using a molded cup or piston that separates the upper from the lower chambers. When the handle is pressed, the plunger pushes against the relief valve, making it tilt and release water from the upper chamber to flush
Applications:
Let’s look at the different situations where you would choose either a diaphragm or piston flush valve in your facility. There are three main factors to consider: restroom traffic, water quality and operating conditions.
Diaphragm -
The diaphragm flush valves operate better in high traffic, poor water conditions, and high back pressure. It is also considered durable, reliable, and low maintenance cost. This is the right choice for your average commercial restroom. Most situations will call for a diaphragm flush valve as it is cheaper and easier to repair and maintain. The diaphragm has a static sealing mechanism which seals water more rapidly. It does not have a “wear surface” as it alternates between compression and tension. This means parts will not wear out as easily.
To date, the biggest feature of the Sloan diaphragm is the dual filter diaphragm.
“The real game changer was the dual filter. With that in place, even if a small piece of debris gets clogged in one of the holes, another one is still open to allow the flush valve to flush properly. So spending a little more upfront by purchasing a dual filter will save you a ton of money in repairs and labor down the road,” according to Skye Cook, Sales Manager at Best Plumbing Specialties.
Piston -
A Piston flush valve maximizes a low-pressure weak system. It works great in low-pressure environments, especially less than 20psi. This system has a longer stroke length giving a weaker system more time to stabilize. If your plumbing system has occasional dips in water pressure, a piston valve might be the right choice. It performs well in situations where water quality is great. Keep in mind that more maintenance is required with pistons than with a diaphragm.
If you are working in a low-pressure low-traffic environment and want a more stable system, piston flush valves may be the way to go.
What about Sensor-Activated Options?
Both diaphragm and piston flush valve technologies come in manual and sensor-activated models. There are also retrofit kits available for both styles of flush valves.
“Picking the correct flushometer technology for an installation calls for good, current information about how and where the valve will be used. And manual or electronic activation has nothing to do with the diaphragm vs. piston choice”, Mike Gipson, Sloan product line manager, stated.
Conclusion:
Understanding your facility and system is the first step to finding the right flush valves. Whether your buildings have diaphragms, or piston valves, Best Plumbing Specialties has all of the internal repair parts you will need to keep them up and running. From diaphragm drop in kits, to piston kits, handle repair kits, to sensor modules, we can help you keep your restrooms in service.