Commercial Plumbing Tips: Signs a Toilet/Urinal Flushometer Needs Adjustment or Repair

Commercial Plumbing Tips: Signs a Toilet/Urinal Flushometer Needs Adjustment or Repair

Mar 27th 2024

Commercial flushometers are designed in such a manner that they’re supposed to conserve water with each flush, using, in theory, only what is needed and no more. Some flushometers can even be adjusted in the field, in order to optimize the use of water with each flush cycle.

However, flushometers are also mechanical devices that can break down over time, as a result of age, or through misuse. Here are some of the more common problems associated with malfunctioning flushometers, how to identify them, and what you may be able to do about it, including what commercial plumbing parts may be necessary for repair.

1.The flushometer won’t flush
A flushometer might not flush if either the control stop or the main valve supply is closed. Open them if they are closed. In addition, a worn-out handle assembly can cause a flushometer to fail to flush. Either replace the entire handle assembly or the parts that have worn out.

In addition, piston flushometers might experience wear around the piston lip seal, in which case the piston will need to be replaced. A flushometer also might not flush due to insufficient water pressure, in which case you might need to address a greater issue with the plumbing system.

2.The system continuously runs
You know the sound of a toilet that continuously runs; on residential toilets, the issue could be a worn flapper or a degraded flapper seal. Oftentimes, a similar issue can cause a commercial toilet flushometer to run continuously.

If the flushometer has a diaphragm, in some instances continuous running can be caused by debris that has gotten under the diaphragm or is blocking the diaphragm bypass. The diaphragm assembly could also be otherwise compromised; in either case, the entire assembly may need to be replaced or the diaphragm bypass cleaned out.

If the toilet flushometer has a piston, then continuous running could be caused by debris that has gotten under the piston or blocking the bypass orifice. It could also be caused by a worn relief valve seat; in any of these situations, the piston assembly may need to be replaced.

In addition, continuous running can be caused by low line pressure (with either piston or diaphragm type toilet flushometers), in which case the cause of the issue is not equipment.

3.There’s a chattering or rattling noise inside the valve during operation

commercial plumbing

A chattering or rattling noise inside the valve during operation or right near the shutoff could indicate that parts have failed or are soon going to fail. Common causes are relief valves or diaphragm assemblies that are wearing and need to be replaced.

A separate but equally disconcerting noise is a hard “thump” sound that (with piston flushometers) could indicate that the piston assembly needs to be replaced or that the line pressure is too high and needs to be adjusted.

4.The flushometer handle is leaking water
Flushometers can potentially leak water at a variety of locations, but flushometer handles, which are in constant motion and unfortunately are sometimes roughly abused by users, will sometimes spring leaks as they break down.

The good news is that for most flushometer handles, you may be able to replace certain parts of the handle assembly instead of the whole thing; oftentimes the handle seal has degraded and started to leak and so needs to be replaced. If you can’t identify the part that has failed, replace the entire handle assembly.

5.The flush length is too long
One common cause of a flush length that lasts too long is an obstruction in the diaphragm bypass orifice. Check the bypass orifice and clean it or clear it out. Take care not to damage the diaphragm or expand the orifice. If that doesn’t solve the problem, you may need to replace the diaphragm assembly.

An excessively lengthy flush may also be caused by low water pressure, which will have to be adjusted so it can the relief valve to seat properly.

6.The flush length is too short

commercial plumbing

If the flush length is too short (that is, the valve closes without adequate flushing) the problem may be that either the handle assembly or diaphragm assembly is damaged. It could also be that the parts installed are not properly aligned with the correct flush volume. If the parts are damaged, replace them with new parts; if the flush volume is misaligned, replace the old diaphragm or handle assembly (or both) with parts that are rated for the proper flush rating.

Pick Up Commercial Plumbing and Toilet/Urinal Flushometer Parts Here for Less!
Ready to save money on the top flushometers from the top residential and commercial plumbing manufacturers in the industry, such as Delany, Moen, Sloan, Zurn, American Standard, and others? In addition to our broad collection of flushometers from premier manufacturers, we also carry an expansive range of flushometer parts, most of them genuine replacement parts from the same manufacturers. We also carry a wide range of parts to support commercial plumbing services, including flushometer parts, hydrants, faucet parts, and a wide range of commercial plumber tools. offers these high-quality repair and replacement commercial and residential plumbing parts at excellent prices and our customer service is second to none. Make sure you contact us if you can’t find the parts(s) you need on your own or you simply aren’t sure what you need in the first place.