I had a non return valve fitted recently and am just inspecting the work performed. The install is of a buffalo valve and a picture of the install is available here. https://ibb.co/DWS5NS9
The non return valve was fitted because (incredibly!) the foul water drain is getting overwhelmed with rain water and backing up a vertical height of 2+meters into my home.
I am however concerned with the way the non return valve has been fitted. It is currently pointing down stream of the flow of water of the sewer and protrudes into the flow of the sewer. If the sewer is becoming overwhelmed and the water is rising, i kinda wanted to be sure it is definitely going to force shut and not become partially open / back up with force of water and/or turbulence. I might be unnecessarily concerned here?
I thought the pipe joining the sewer would need cutting back so the non return valve wouldn’t encroach in the flow of the main sewer (this is certainly what the fitter described to me when pricing the job). This doesn’t seem to be the case in my fitting, it seems to have simply been popped on the end. Curious if this might cause future problems with the non return valve snagging things in the main sewer flow.
Appreciate insights any of you have that are more experienced in these matters than me.
Thank you!