I recently had a backflow valve installed. I am concerned that the o-ring on the screw top above the valve expands to the point that it falls off when I open the lid. When installed, it was lubricated with industrial food grade silicone lubricant as instructed by the plumber. I believe that this o-ring expansion has been the cause of a minor failure already. What can I do to stop the o-ring from expanding and failing? Is it normal to have to replace the o-ring every time the cover is opened?

Hi Lstrong...

Are we talking about a backwater valve in a sewer drain pipe or some other kind of backflow valve? Let me know more about the application and then I can tell you more, OK?

Mark

Yes, the backwater valve was installed in a 6 inch clay sewer line. I is a DWV Backwater Valve, PVC, for gravity flow.

Then I would say that, yes, it is normal for that ORING to pop off when you remove the cover.

Every time I remove one of these covers the ORING falls off, I place it back on correctly and that is usually the end of it... ;) I have never had one dry out or be non-replaceable.

If you have any real concerns here, you could try contacting the manufacturer of your backwater valve and see if they could send you one or two extra ORINGS.

You could also get a tube of GASKET MAKER or gasket sealant and try this on the ORING... see if increases chances of bonding.

More questions, let me know, OK?

Mark