Page 1 of 1

Shower and Sink to Gray Water and P-Trap Questions?

PostPosted: Sat Nov 07, 2015 9:09 pm
by ywhic
Figured I'd ask.. I don't see any recent posts addressing this on here..

I am doing a shower install on my CC project and want to drop the drain thru the floor of the trailer, then do the 'P-Trap' which would be 2" of course, and come back up and over then into the 'Gray water' holding tank.. I don't want to elevate the shower stall at all.. I have a brand new 3/4" floor to put a hole thru..

I also planned on doing a sink 2" p-trap under the sink per norm.. then just tying the 2 lines together under the trailer just before the 'Gray water' tank so I only need 1x hole put into the holding tank..

How much clearance would I need above the holding tank to get this worked out?? anyone got dimensions on a 2" P trap?? and/or should I use the 'low-profile' P-trap if there is such a thing and if so would it matter much on this idea as I still need to come in either high on the side or on top of the holding tank..

I figure 2" PVC or ABS is the same OD of 2 3/8".. so I need at least that and then what about the 90' elbow down?? and how long is the 90' elbow 'spigot' length..

Anyone got REAL pictures of this type of setup on there rigs??

Re: Shower and Sink to Gray Water and P-Trap Questions?

PostPosted: Sat Nov 07, 2015 10:54 pm
by MtnDon
An alternate solution to the P-trap.

Can be used vertical or horizontal. Takes little space horizontal. Also eliminates the need to winterize the drain / trap. I use one in our cabin to make winterizing easier. It is not accepted by the residential plumbing code but that's mainly because submitting it for testing costs $$. They do work well.

Available from several sources. Google Hepvo

Re: Shower and Sink to Gray Water and P-Trap Questions?

PostPosted: Sun Nov 08, 2015 12:19 am
by M C Toyer
Ditto on the Hepvo waterless traps. I' used on both my sink and shower, 1-1/2" is more than sufficient and 1-1/4" is available.

You should be able to just use a single trap ahead of the gray water tank after you tie the two drain lines together, assuming the shower and sink are fairly close to one another.

Here's the waterless trap tucked up tight below the sink and the drain line pushed far back against the wall. Makes more room for the tankless heater, water pump and two fresh water tanks.

Image

I have a double floor beneath my shower and the gray water tank and waterless trap are suspended about half way through so made a rough cut out to accommodate. The trap is fully accessible from below the trailer.

Image

The shower pan sits directly over the gray water tank and trap.
Image

Re: Shower and Sink to Gray Water and P-Trap Questions?

PostPosted: Sun Nov 08, 2015 12:06 pm
by McDave
+1 on the Hepvo.
McDave

Re: Shower and Sink to Gray Water and P-Trap Questions?

PostPosted: Sun Nov 08, 2015 1:42 pm
by ywhic
@Mc Foyer.. What model is that gas water heater any pics on how you made the heat flu??

Any issues stepping 1 1/2" PVC to 2" ABS??

Re: Shower and Sink to Gray Water and P-Trap Questions?

PostPosted: Sun Nov 08, 2015 11:54 pm
by M C Toyer
I think the tankless water heater is an Eco Temp but there are a couple very similar. About $100 on Amazon.

The plenum/flue is a standard HVAC torpedo boot. It only requires minor crimping to fit around the exhaust end of the tankless, a few pop rivets to hold, then sealed with high temp duct tape. I don't remember now but there may have been a shroud with a screen or baffle on the heater I removed first.

It vents horizontally through a triple wall exhaust vent I fabricated from some off the shell parts. On the exterior I just have a small hinged metal plate that matches the siding to cover the exhaust hole but I suppose a metal dryer vent would work but might blow open when travelling.

Image

Image

Interior
Image

Exterior before siding installed
Image

The back side of the heater stands off the cabinet wall about 2 inches. I only put the metal on the wall with the exhaust because the first hole I cut interfered with the fender well and I had to adjust the placement. It stands off the base of the cabinet about 3 inches to facilitate the propane and water supply lines and the drop down battery box for the auto-ignition.

Seat of the pants on the technical aspects of plumbing: An old pro once told me the only three things I needed to know were excrement won't flow uphill, don't chew your fingernails, and payday is on Friday. So far all has worked out for me.

I'm sure some others will weigh in but I would think going from a smaller to a larger drain pipe would not present any particular problems. I did not mention that my gray water tanks are each vented from the top with a small rubber hose just tacked above the tanks under the trailer. I use small (1-1/2" or maybe 2") bayonet valves to drain.

Image

Re: Shower and Sink to Gray Water and P-Trap Questions?

PostPosted: Mon Nov 09, 2015 11:11 am
by McDave
@ M C Toyer,
Thanks for those pics, I may need to use that concept for venting H20 heater.
McDave

Re: Shower and Sink to Gray Water and P-Trap Questions?

PostPosted: Tue Nov 10, 2015 8:28 am
by ywhic
My proposed shower and sink have 2".. Suggestions for drains?? Do I do ABS or PVC drains and then adapt to ABS??

Re: Shower and Sink to Gray Water and P-Trap Questions?

PostPosted: Tue Nov 10, 2015 3:07 pm
by M C Toyer
Al -

I seem to recall my shower drain's tailpiece was 2" and I just used a reducer ahead of the waterless trap. The volume of water I use in the sink and the shower is so low I have never noticed a problem with slow drainage.

Just general reference to others who might want to use a tankless heater, the Eco Temp comes with a hose and spray head, but not a mixing valve. You can adjust the temperature and the flow rate on the heater but in my case the heater is out of reach from the shower. In retrospect I should have included a cold water supply line and mixing head for fine tuning. The kitchen sink, actually a bar sink, came with a faucet and two valves so it is not a problem to mix or just hot or cold separately.

Re: Shower and Sink to Gray Water and P-Trap Questions?

PostPosted: Wed Nov 11, 2015 12:34 am
by M C Toyer
ywhic wrote: Do I do ABS or PVC drains and then adapt to ABS??



Al -

The Hepvo waterless trap has compression fittings on both ends so will work fine with either PVC or ABS.

Here's the "internet answer" to cementing the two different materials in a non-pressurized system:

http://www.homedepot.com/p/Oatey-4-oz-ABS-to-PVC-Transition-Cement-309003/100344275

Or in lieu cement you could use the flexible neoprene couplers:

http://www.homedepot.com/p/Fernco-2-in-x-2-in-DWV-Flexible-PVC-Coupling-P1056-22/100096490?keyword=neoprene+plumbing+couplers

If you need to cement a spigot on your gray water tank I would recommend you use the same material for the spigot and the tank. The joint will not be under pressure but since it will be located after the trap may hold some liquid when moving and when full.