Waste hose sizes

[Werner]

We have purchased a 1981 Defever 41. First job is to replace a old, permeated waste system. The holding tank and all hoses have now been removed. (Wish I was 30 years younger and 2 ft shorter due to the tight spots to get into to do this job) So now its back to the bilges to run the new hose. My question is about the hoses that attach to the heads.

Both heads are plumbed to a holding tank, with no direct discharge. The holding tank has a macerator pump to pump overboard where allowed, and a deck pumpout for use at marinas.

One toilet is a manual with a short run and uses 1 1/2 hose. No issues with that toilet. The other is a electric whose hose starts from the macerator at the toilet with a one inch hose, which then goes into a 1 1/2 inch hose and on to the holding tank. This run is quite long (12 ft) and when I removed the old hose it had closed down to a opening of roughly 1/2 to 3/4 inch.

Would it not be better to run the hose from the toilet macerator all the way to the tank using hose that is the same diameter, which would mean a 1 inch line. My thinking is that the macerator pump would lose pressure as the waste moves from the one inch to the 1 1/2 inch hose. If it was all the same it would move the waste better I would think. The waste in the hose does need to be pushed uphill during the last few feet to get into the top of the holding tank.

 

[Lou_tribal]

On mine it is 1 inch all the way to the tank.

 

[Capt.Bill11]

Even with the 1" hose you get build up.

You need to acid flush the lines from time to time.

You get less build up with fresh water flush heads.

 

[psneeld]

If it is going to gravity feed much of the way or you can make it so.....you get much less build up than if it sits in the hose.


My 1 inch hose from the aft macerator runs about 12 feet total but only the first 2 go from macerator to a vented loop and the rest drains to the Electroscan. The part that drains has very little buildup after 3 years. Where it sits in the hose, as a full time liveaboard...it builds pretty quick in just a year.

 

[Werner]

Thanks for the advice. So it should be OK to go with all 1 inch on the toilet with macerator? It would certainly be easier than running new 1 1/2 inch and should keep the pressure higher to push the waste through.

 

[psneeld]

Hard to guarantee success without seeing the whole setup...and even then.


All I can say is if the macerator only has to push a few feet uphill, then the rest is down...12 feet should not be an issue ....but it might be prudent to check with the toilet manufacturer.


I am mostly speaking for separate 12V macerator pumps...but most rubber impeller pumps can pump that far easily.


I have made that assumption on your toilet macerator...is it a rubber impeller type?

 

[HeadMistress]

Both heads are plumbed to a holding tank, with no direct discharge. The holding tank has a macerator pump to pump overboard where allowed, and a deck pumpout for use at marinas.

One toilet is a manual with a short run and uses 1 1/2 hose. No issues with that toilet. The other is a electric whose hose starts from the macerator at the toilet with a one inch hose, which then goes into a 1 1/2 inch hose and on to the holding tank. This run is quite long (12 ft) and when I removed the old hose it had closed down to a opening of roughly 1/2 to 3/4 inch.

Would it not be better to run the hose from the toilet macerator all the way to the tank using hose that is the same diameter, which would mean a 1 inch line. My thinking is that the macerator pump would lose pressure as the waste moves from the one inch to the 1 1/2 inch hose. If it was all the same it would move the waste better I would think. The waste in the hose does need to be pushed uphill during the last few feet to get into the top of the holding tank.

Your biggest problem is a 12' run from one of the toilets to the tank...which unless your toilet is one of the newer high end all china "throne" with much more powerful pumps, is about twice as far as your toilet can move bowl contents without a lot of help from gravity. That would be true whether your toilet is brand new or has a 1" hose all the way...and the uphill run at the end only compounds the problem.

There are three possible solutions: 1. It MIGHT be possible to reroute the discharge hose to give you the help it needs from gravity...2. a second tank for that toilet. If it's a toilet that's seldom used, it can be a fairly small (12-15 gal) tank. And it should make re-hosing a LOT simpler job! or 3. this gives you the excuse you need to upgrade to a more powerful toilet.

If you have to stick with a single tank, because the inlet fitting on the tank is 1.5", the best solution would be to replace the 1" toilet discharge fitting with a 1.5"--which you can get from Jabsco (since Jabsco is the only toilet mfr who uses a 1" discharge on their toilets, I'm assuming your toilet is a Jabsco) which will let you use 1.5" with no splices--each of which is a "bump" that catches waste and sea water minerals to create buildups.

Then, because you only want to have to this job ONCE, there's the matter of which hose to use and/or whether you can use hard PVC (whether that's likely to cause more problems than it solves...so if you'd like to do a little one-on-brainstorming about the best way to solve all these problems, send me a PM that includes your email address.

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
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