Deep bury gate and check

[Ambassador]

Hey guys, I could really use some advice here as I deal with this sewer backflow during flashflood scenarios.

I planned to drop a gate or a check below the bathroom floor (via a wall access panel) in a tight space between the stack and the exterior wall. After tearing up the bathroom floor, I discovered a double wye was blocking the only place I could put it.

So now I'm outside, an 8-10 foot dig, but at least now I can fit both a check and a gate on the line. I have a couple of sioux chief deep bury checks (online order required two), and these are quite nifty for cleaning and servicing from ground level.

I also picked up this massive Nibco epoxy coated resilient wedge valve (PCR 619-RW) with push on ends. It operates VERY smooth but I noticed it has the rubber wedge as opposed to sharp knife gate. I don't think I'll have any trouble stopping whatever comes through that sewer with this, but could it be a problem that it's not a knife... And what about those push on ends?

Anyways, I guess I need to put in a manhole if I do any gate, correct? I'm trying to decide if it's worth it because that's a lot of work for me! Unless, do you guys think I could just put the gate down there and not need to service it? I could try to encase it to keep dirt away and then send some schedule40 up to grade for the key to access. Then maybe just turn it a few times a year to keep it moving?

Otherwise perhaps just putting in 2 Sioux Chief deep bury checks would be sufficient? I've seen that some of those PVC check lids can blow in high pressure scenarios, but I've also heard that the brass flappers on those heavy duty checks won't open sometimes. So that's why I like the idea of having a solid gate down there with the PVC checks... just in case.

Another thought... if I run into a 6-inch pipe, is it okay to just use a standard 4 to 6 inch fernco coupling? Would you encase the rubber couplings in concrete?

I really appreciate any feedback you guys can offer. Thank you!

 

[Geofd]

it may be a pain to install some sort of access so if you need to service you have plenty of room to work if its reg pvc can you use a reg glued type fitting or 6by4 mission coupling

 

[Ambassador]

In other words, you would not install the gate without access, correct?

 

[frodo]

correct. install a minimum 36'' wide pit

 

[Geofd]

In other words, you would not install the gate without access, correct?

i would definatley want access to your valve and check valve

 

[Ambassador]

Well the manhole is a lot of work and it's very expensive. Too expensive for this little homeowner.

Those fusion bonded epoxy resilient wedge valves and plug valves are designed for deep bury scenarios. Municipalities use them for just that.

I found a section of 12in clay sewer line in the woods here that's about 3.5' long that I will use as a soil pipe to cover over the valve, then I'll bring stone up to the bonnet, and then I think I'll put 6" sch40 inside this over the 2" nut and bring it 8' up to grade to access with an 8' key.

The Val Matic cam-centric plug valve is better for use with raw sewage and solids than the nibco resilient wedge valve, but both will work. I like that the nibco valve has the push on end connectors. The cam centric plug valve is flanged and would need additional flange adapters, but it's also 1/4 turn (without the deep bury worm gear). If you pay the extra for the worm gear you can place the valve with the plug horizontal and this keep the solids off of the bottom seal. You lose the quarter turn torque, but you also avoid water hammer.

I think most deep bury scenarios use mechanical joint connections because they hold up better with movement underground.

Anyways, the NIPSCO valve was $390 at Menards and the Val Matic plug valve with the worm gear and flange adapters quote is about $1000. I'm going to stick with the NIPSCO resilient wedge valve because the plug valve is backordered and will take too long for delivery.

Wish me luck in 10 years when I'll actually need this thing to work!