Holding Tank Pipe Attachment

Ericbsc · October 01, 2009, 11:43:40 AM

I'm sure there is a simple answer, but here goes. Attaching the 3" pipe to holding tank. Bulkhead fitting says to drill 4.5" hole. The nut that goes on the backside is much bigger than that. What magic do you use to get it thru. the hole that is smaller than the nut?

redbus · October 01, 2009, 02:30:34 PM

I don't understand the fitting you are using with a nut on the inside. A picture is needed.

gumpy · October 01, 2009, 04:23:08 PM

Most use welded on fittings.

If you're going to use a nutted fitting, you'll obviously have to cut a larger access hole in the top, and then cut a piece to fit over the access hole to seal it. You can use that
access hole to clean the inside of the tank, should you ever need to.

CindyandJohn · October 01, 2009, 06:04:27 PM

I had the same scenario - and what I installed was a product called Aquasavers. Basically they are 8" access ports which are water tight and can be opened for cleaning the tank. Here is where I got them - http://aquasaverbypjbcompany.com/ I have no interest in the company other than that I met the guy at an FMCA rally and they are what I needed. If you want pics let me know.

John

Ericbsc · October 01, 2009, 06:48:36 PM

What about a uniseal. Round rubber that the pipe slides into. Look at the tank depot. Anybody used this?

NewbeeMC9 · October 01, 2009, 07:46:46 PM

My opinion, for what its worth, even though I don't like it for the black tank especially below the waterline

. it may work for the vent pipe attachment and you may never have a problem if you don't fill it up all the way.

Can you get a threaded fitting spunwelded into it?

brando4905 · October 02, 2009, 06:04:34 AM

I have Uniseals on top of my tank where the toilet and shower/sinks go in, my tank thickness made them really hard to push the pipes through(tank a little thicker than Uniseal called for). Had to grind pipes down to a taper and use some slickem' to get them through. They do a good job on top, I wouldn't use them on the outlet.

Chuck Newman · October 03, 2009, 10:45:33 AM

Cindy and John,

Which tank or tanks are you using them on? Are they top or side mount? I presume you are using them to clean the tanks? Is 8' enough room. What is the quality of the gasket material?

Thanks,

Chuck

Ericbsc · October 03, 2009, 07:51:49 PM

I went with the bulkhead flange, but now need to cover that extra hole. I am going to use the uniseal to go thru. the roof. Looks like it will make a good seal. Next stupid question. Why abs plastic instead of pvc. Pvc is much easer to find. I used abs because all the fittings for sewer are abs. Just didn't know why

luvrbus · October 03, 2009, 08:27:00 PM

Eric, you can use PVC it was just for a long time DWV fitting were harder to find for PVC but that is not true any longer and they have glues now to bond the PVC and ABS together also.
They are the same OD and PVC is stronger than ABS lot of people use ABS because there is no need to prime it and if you use purple primer on PVC it looks tacky but I use the clear as I don't have a inspector checking to see if I primed it or not that is one of the reason for colored primer.
Last I bought PVC- DWV was cheaper than ABS but it had a foam core so I used sch 40 PVC you can use either one thing ABS has just one type fitting and PVC has a DWV and a pressure type.

John316 · October 04, 2009, 07:15:09 AM

The reason that we used abs was because when it us glued then it actually melts the two together, making a better bond. We thought that was better for the bus because the bus moves and viberats. The PVC just glues. Not melts.

God bless.

John

Posted by my touch.

luvrbus · October 04, 2009, 07:33:18 AM

John, ABS is a light weight materail it has a cellular core a 1 inch piece of PVC will weigh more than a piece of 1 1/2 inch ABS which may be a good thing for conversion but ABS is not durable for vibration the fitting are the first to break that is the reason they strap it so much in the S&S jobs.

good luck

John316 · October 04, 2009, 08:10:45 AM

Thanks for the explain, Clifford. Makes sense to me. Bummer our thinking was flawed. We went with abs. Ouch.

God bless.

John

CindyandJohn · October 04, 2009, 12:43:59 PM

Chuck,

We installed the aqua savers on the sides of each tank so they are frequently subject to water over the top level of them. I have had them for almost three years and no issues. I feel the 8" opening is more then sufficient for cleaning. I would not go bigger than that. I installed them on three tanks which I purchased from American Tank. We bought two 115 Gallon heavy duty tanks for fresh and grey water and an 80 Gallon heavy duty tank for the black water. the side walls of the tanks are about 1/8 - 1/4 of an inch think. Really nice tanks. If you want to see some pics let me know - I would have to dig for a few or just take some new ones but I would be more than willing. I am very pleased with them.

John