macerator hose removal advice

[jdrutten]

I'm going to disconnect my macerator from the holding tank since the hoses stink and we're on a lake and won't be using it any time soon. Yesterday, as I was starting the process of removing the stinky old hoses, it occurred to me that I really would prefer that I don't screw this up. My holding tank is connected to the 1-1/2" macerator hose with a male thread-barb adapter. The macerator input receives this hose with a barb. The macerator output is 1" barb which is connected to the seacock.

I bought a 1-1/2" threaded male cap to take the place of the holding tank adapter but with my limited experience, I'm concerned that I may not be able to successfully remove the adapter without damaging the holding tank because of the evidence of some sort of sealant that was used at the holding tank-adapter connection. I'm wondering if I should instead use a flexible "Qwik Cap" (elastomeric PVC) over the adapter so I could just leave it in place. Or maybe some other option?

My other hesitation was how I should properly cap off the seacock. It would simply need to prevent the disastrous sinking of the boat in the event that the valve failed. Probably it should be bronze, but would there by any issue using a 304 stainless steel cap from the hardware store?

 

[JoeWhite]

The barb adapter will come out of the white female outlet. Then use the PVC cap with plumber's tape and pipe thread paste.
Use 2 pipe wrenchs to remove the barb. One to hold the outlet in place and to remove the barb.

 

[Ralph Johnstone]

Nice write up. Just like I'm looking over your shoulder. Actually, I'm kind of cheating here because I did an identical job years ago on my '99 H-310 holding tank.

A few tips : The MIP X hose adapter shown in your first picture SHOULD come out without too, too much hassle. Mine would have been about five years old when I removed it and it was reluctant to budge. Hunter's pipe dope was absolute crap. Any pipe sealant is required to remain permanently soft. This crap turnsto powder as you will soon see. If you do find it sticking, use a hair dryer on it (your wife won't mind) and it will come right out. Remember the back up wrench as mentioned by @JoeWhite .

Teflon tape and sealant for the new MIP PVC plug. The best pipe sealant would be :

On to the thru-hull. I'd prefer to use a bronze (even brass in this case) plug for sealing off the macerator thru-hull. If you must use SS, IW remove the 90° bronze street el and rinse the interior of the valve above the ball. Dry the interior thoroughly and maybe fill with grease to ensure you don't set up a galvanic corrosion cell. But only if you're OCD .

 

[jdrutten]

Excellent! Thanks for the helpful comments. I hadn’t considered the double wrench approach but that makes a lot of sense. And I briefly considered a heat gun, but wrote it off due to the melting/deformation risk. A blow dryer certainly seems more appropriate.

I suppose I’ll include a bronze plug in my next Defender order. But Ralph, I’m interested that you suggested brass as a bronze alternative over stainless. Is the idea that the nobler stainless would corrode the thru-hull faster than the nobler thru-hull would corrode the brass?

 

[Ralph Johnstone]

I’m interested that you suggested brass as a bronze alternative over stainless. Is the idea that the nobler stainless would corrode the thru-hull faster than the nobler thru-hull would corrode the brass?

Brass, bronze, and SS are roughly in the same galvanic neighbourhood so I didn't really give it too much consideration but yes, you're right, in theory the SS could eat the bronze thru-hull after a few centuries. The reason for mentioning the brass plug is that they ARE readily available in big box stores near you. The chances of a brass plug corroding through when surrounded by fresh lake water are so small, even me with my OCD (or CDO as we like to call it) it's not be worth considering. However, it's NOT according to ABYC who is more OCD than I and does not differentiate between fresh and salt water. I wonder if they sleep in their PFDs as well ?

 

[shemandr]

I'd suggest an ample supply of disposable diapers positioned under the hose and deployed in a line between the tank and the bilge. Without the opportunity to flush the line it's a good bet it's nasty inside. In my case it didn't come off willingly. So while I planned to be neat - it didn't end up that way.
Cutting the hose in-between the fittings may make it easier to remove.

 

[jdrutten]

I took two wrenches, permatex, disposable coveralls, and diapers to the boat last night. Things went reasonably well despite my trepidation. I used twice as many diapers (puppy pads) as I thought I would need, and probably could have put down a couple more. The remaining sanitation hoses (head-to-tank, pumpout, and vent) run vertically, so I think I'm through the worst of it now. I'm letting the permatex cure for a day or so, but am planning on filling the tank with water and food coloring for a couple days and seeing what happens. Thanks again for the helpful ideas!

 

[Ralph Johnstone]

Nice job. No need to let the Permatex cure as it doesn't. It remains soft for keeps, which is what you want.

Give it your worst, all you got. Call over the other boating neighbours to party and feast on hot tamales, chili and curry then show them to the head. NOTHING is going to make that joint leak now.

 

[jdrutten]

Call over the other boating neighbours to party and feast on hot tamales, chili and curry then show them to the head. NOTHING is going to make that joint leak now.

I guess you haven't met my dock neighbors.

 

[jdrutten]

As a follow up to my installation, the thought occurred to me that I may have over-tightened the fitting. I went hand tight and then put a wrench on it for another turn, as is often recommended for PVC fittings. A subsequent forum search revealed a comment from Peggie suggesting no more than 1/4-1/2 a turn, and that an over-tightened fitting could take a month before failing. Then again, hand tight with the permatex might be different than hand tight without the permatex. I'm considering either backing off the plug for a half turn, or maybe just buying a new plug fitting and doing it over. I put water in it and it seems to be holding, so part of me wants to just leave it, but would of course prefer not to have to deal with a leaking tank at some point.