Oh no... I just replaced head sanitation hose

[SV__Grace]

I haven't seen any mention of double clamping- using two hose clamps on a through hull fitting is always a good idea.

Avoid perforated worm gear clamps and use non-perforated or solid band or T clamps for important or problem connections. (ear clamps for fuel). I've learned the hard way that the type of clamp is important. Don't buy cheap clamps, you get what you pay for- SS by trident or other credible source.

Heating the hose makes it pliable and a better seal when clamping. I've always used a heat gun but like the hot water idea!

[peghall]

I haven't seen any mention of double clamping- using two hose clamps on a through hull fitting is always a good idea.

ABYC standard calls for double clamping all hose connections in a sanitation system and all hoses connected to below-waterline thru-hulls.

Heating the hose makes it pliable and a better seal when clamping. I've always used a heat gun but like the hot water idea!

I always used a blow dryer 'cuz it does the job without risk of OVERheating that a heat gun has if you're not very careful with it, and it's faster and easier than a bowl of hot water. I kept a portable one with a folding handle in my tool box.


And btw...heating a hose makes it a lot easier to pull off a fitting too.


--Peggie

[bdbranson]

Can you find a short male adapter that is size A on one end and size B on the other, and essentially transition from one hose size to the other?

I have successfully slipped a slightly too tight hose onto a solid fitting by hearing the hose with a heat gun.

Not sure how much it would shrink or be able to clamped to a smaller diameter, but interested to see what happens.

Good luck!

[Sohum]

You should build up the barbed end(sounds like that’s what your attaching to). I’ve used Teflon. I like the shrink tube tech better. It would take excessive heat, where the hose distorts, to reduce ID. From my limited experience with marine grade hose, this stuff is rigid, and difficult to constrict. ( I use hot water to soften the pipe before connecting).

[Pandor]

Thanks to everyone for all the really helpful advice. I have successfully finished the hose installation. I only needed to heat up the ends of the Dometic PCV hose to make it pliable enough to compress with the hose clamps. I used both the hot water method and a hair dryer. But the hot water worked much better/ faster where I was able to use it. I also double clamped with good Scandvik hose clamps. The good clamps are really worth the money.

By the way, I also spoke to a local marine plumber. He said they always heat up the hard PVC before clamping, even when on the correct size fittings. He said he uses a hair dryer. But again, I found the water was better.

[Geitz]

Originally Posted by Pandor

At any rate, I had already bought and cut to size Dometic OderSafe hosing for replacing it. This is the hard and stiff PVC type. So, I forged ahead hoping that I could clamp the hose tight enough with hose clamps so that it would seal. The metric fittings seem just shy of 1.5 inches.

Is it possible that your boat's hose barbs are for 32mm (1 1/4") ID hose, not 40mm (1 1/2")? On my French boat, the barbs are 40mm and the 1 1/2" hose is a very tight fit.


Mike

[nmccubbin]

We have never used sanitation hose.
I am not sure I had even heard of it when we built either of our two boats
We used industrial hose intended for water and steam up to 50 psi.
The wall thickness from 1/2" to 3" is about 1/4"
It is reasonably flexible, and squeezes down for smaller fitting quite well. Usually needs a heat gun to fit standard fittings.
Last installation is 18 years old with no odor issues.
We have dismantled about head discharge hoses about 3 times to bash them so that the calcium scale falls off

[Pandor]

Stupidly, I didn’t bother to measure the barbs while the hose was off. But on the other hand, I’ve only ever seen 1.5 and 1.0 inch sanitary hose available in the US. Is there such a thing as 1.25 inch?

[Geitz]

Originally Posted by Pandor

Stupidly, I didn’t bother to measure the barbs while the hose was off. But on the other hand, I’ve only ever seen 1.5 and 1.0 inch sanitary hose available in the US. Is there such a thing as 1.25 inch?

There must be, since Groco offers a hose barb for it:


https://www.groco.net/products/fitti...-standard-flow

[Geitz]

In looking at ASAP Marine, a UK company, there's also 38mm ID sanitation hose and a bronze hose barb.



https://www.asap-supplies.com/produc...mm-hose-404174






Mike

[Pete7]

Originally Posted by Geitz

In looking at ASAP Marine, a UK company, there's also 38mm ID sanitation hose and a bronze hose barb.



https://www.asap-supplies.com/produc...mm-hose-404174


Mike

That is pretty standard in the UK, surprised there is 3/4" or 1" hose unless its for the inlet which is 3/4" in the UK.

BTW the Trudesign valves 1.25 and 1.5" have the same size internal bore through the valve, only the hose tails vary.

[Pandor]

Originally Posted by Geitz

In looking at ASAP Marine, a UK company, there's also 38mm ID sanitation hose and a bronze hose barb.



https://www.asap-supplies.com/produc...mm-hose-404174






Mike

Yes, 38mm is the standard. That is the same as 1.5 inch I installed.

Originally Posted by Geitz

There must be, since Groco offers a hose barb for it:


https://www.groco.net/products/fitti...-standard-flow

I'm not suggesting that 1.25 inch hose doesn't exist. I've just not seen sanitary hose in that size.

[Geitz]

Interesting that Groco's barb is 40mm and Maestrini's is 38mm, both for 1.5" ID hose. I can attest to the fact that 1.5" ID hose on the Groco 40mm barb is a very tight fit............


Mike

[Cheechako]

Originally Posted by Pandor

Thanks to everyone for all the really helpful advice. I have successfully finished the hose installation. I only needed to heat up the ends of the Dometic PCV hose to make it pliable enough to compress with the hose clamps. I used both the hot water method and a hair dryer. But the hot water worked much better/ faster where I was able to use it. I also double clamped with good Scandvik hose clamps. The good clamps are really worth the money.

By the way, I also spoke to a local marine plumber. He said they always heat up the hard PVC before clamping, even when on the correct size fittings. He said he uses a hair dryer. But again, I found the water was better.

CAUTION: I tried that white pvc hose and because it runs small and wont stretch I heated it up to get on some fittings, some went on with hot water some with a hair drier. The BRAND NEW HOSE SPLIT ON THE FITTING WITHIN A FEW WEEKS! Luckily I noticed it because one particular fitting would have sunk the boat. I immediately removed all the work I had done and went back to rubber hose. I assume this means you should never heat that white spiral reinforced hose....

[jdecris]

Originally Posted by nmccubbin

We have never used sanitation hose.
I am not sure I had even heard of it when we built either of our two boats
We used industrial hose intended for water and steam up to 50 psi.
The wall thickness from 1/2" to 3" is about 1/4"
It is reasonably flexible, and squeezes down for smaller fitting quite well. Usually needs a heat gun to fit standard fittings.
Last installation is 18 years old with no odor issues.
We have dismantled about head discharge hoses about 3 times to bash them so that the calcium scale falls off

"... industrial hose intended for water and steam up to 50 psi..."

Interesting. I'm curious.

Do you have a more detailed 'spec' on this "industrial hose" - and a source?

Thanks