Are some checkvalves better than others - Water Backflow Preventer

[Chefwong]

I've had 2 plumbers come out and Ive asked them to look at my current plumbing situation and a corrective action to prevent sewage backup from the lowest point in the house (basement toilet) from happening when the city sewer can't keep up. All 3 just recommend a backflow preventer and I asked are there various types, etc -- and they have advised aside from 2", 3", 4" etc backflows which is just the size of the pipe they will end up working with - they are all the same.


Surely there various designs - some better than others, WITH a cost associated with the different hardware.
Anyone care to to share your experience, brands, models, model types , etc.

 

[hj]

There are several different types. J R Smith, Josam, Wade, and Zurn, for example, ALL make brass fitted cast iron backflow preventers, but they also make combination devices which are a mechanical BFP combined with a manual gate valve to positively prevent backflow. The BFP minimizes the backflow, and if there is some reason why water still leaks back, the manual valve will stop it. The one thing common to ALL backflow preventers is that the inlet pipe is ALWAYS higher than the outlet, so it makes it difficult to install it properly in a "short section" of piping, i.e., without having backpitch on the valve.

 

[Sponsor]

 

[Chefwong]

We got some heavy rain today...
Couple of usual neighbors got some backflow
Not a good benchmark yet, but nary any water .

The one installed was just a regular one without a valve on it.
In Hindsight, after seeing it installed and how it *operates*, I wish I was smart enough to ask the plumber to add a valve right behind it...

I'm not sure how well the pressure buildup is for the pipes ??

 

[Ballvalve]

Check valves vary in quality like women. Ball cone checks are the best, but not really for sewage. Zoeller makes a nice one. I used a 3" PVC ball check once, and its perfect - but very pricy.

http://www.grainger.com/Grainger/ZOELLER-Full-Flow-Check-Valve-2P843?Pid=search

 

[Chefwong]

I wonder how often this happens but here's a slightly disgusting story........but I suppose ya'll have your fair share of poop stories

So this was months after it was installed. I was replacing one of the caps as the plumber reused one and one intial inspection, I could see it was not a tight fit. I never actually saw the guts of the check valve so I decided to remove the cap to see it. Fairly simple mechnisim - brass gate that get's pushed open by water pressure. EXCEPT that the gate was somewhat with a 6 inch turd just keeping it from closing.

Lord knows how long that's been there...but I can see how this could also be a bad case if I got heavy rain as the valve would not actually be closed.

Not sure how much maintenance is required but I do plan to just open her up yearly to make sure there is nothing stopping from keeping the gate closed.

 

[Ballvalve]

You can actually buy clear check valves for sewage.