Loo pipes.

[pandos]

This is just a part of the loo waste system on my new to me boat. It seems the architect of this poo puzzle wanted to make full use of the lavac... much of this 3 Dimensional mess is caused by the bulk in the pipes and the inability to make tight turns.

One part of me says to take it all out and have a simple one pump system, but then it might be nice to have a tank in a boat that can sit on a beach, and also maybe nice to be able to use an electric pump, as a back up and to be able to pump the tank out using either pump...

Question...is there any reason why I shouldn't replace most of this pipework with ordinary PVC rigid plumbing pipe bent to suit and joined to the valves and pumps using short lengths of flexible pipe with clips...

I think in this way it could become a two dimensional, much smaller puzzle...

 

[Boathook]

Think I would start with the wiring.

 

[Geoff Wode]

 

[vic008]

I couldn't find pvc pipe of the corresponding size

 

[Boater Sam]

I use solvent weld domestic waste pipe, neat, good range of fittings and no smell.

 

[harvey38]

Does the toilet work, is there smell leaching from the pipework?

If not and it works, leave it alone.

There is a reason flexible pipes are used, it is easier to route, provides continuous bends so less likely to clog and will flex as the boat moves.

As @Boathook suggests, I think the wiring should be higher up the priority list.

 

[lustyd]

I use solvent weld domestic waste pipe, neat, good range of fittings and no smell.

Is it rated for positive/negative pressure as well as movement? I'd be worried a joint would fail with the various forces on a boat that domestic pipe isn't designed for.
At home, it's very rare for the soil pipe to push water upwards or for any fitting to force water downwards with any pressure, and the pipes in a house are static since the house is stable. None of this is true on a boat and although welds might hold, I certainly wouldn't bet my boat on what is essentially a bit of glue.

@pandos your idea of connecting flexible pipe to solid pipe is obviously a different matter, but I would still worry that without barbs of any kind the pipe could slip over time or with pressure. Roughing up the PVC might improve this alongside the usual double hose clamps

 

[Caladh]

Think I would start with the wiring.

Me too

 

[Boater Sam]

Is it rated for positive/negative pressure as well as movement? I'd be worried a joint would fail with the various forces on a boat that domestic pipe isn't designed for.
At home, it's very rare for the soil pipe to push water upwards or for any fitting to force water downwards with any pressure, and the pipes in a house are static since the house is stable. None of this is true on a boat and although welds might hold, I certainly wouldn't bet my boat on what is essentially a bit of glue.

@pandos your idea of connecting flexible pipe to solid pipe is obviously a different matter, but I would still worry that without barbs of any kind the pipe could slip over time or with pressure. Roughing up the PVC might improve this alongside the usual double hose clamps

Having completed many thousands of pumped lavatory waste systems in houses factories and vans I have no worries about solvent weld coming apart, the clue is in the name - weld -.

 

[lustyd]

the clue is in the name - weld -.

Not all welds are created equal, and it's still just a glue whatever name you give it. You may be willing to bet your life and your boat, but there are standards for good reason on boats.

 

[pandos]

Think I would start with the wiring.

The wiring is a temporary supply to the pump as I could not track the proper supply. It's not really a problem, and doesn't smell of poo poo...

 

[JOHNPEET]

Solvent welded grey PVC was my choice for all waste pipe work except the final connections to toilets, holding tank, change over valve and other fittings. Plenty of choice for fittings available including barbed connectors. Lots of information at the link below including chemical resistance. I also used it for the tank fill lines and pump out line.

PVC Pipe and Fittings | Metric | Inch | Wras PVCU

Systems available for pressures up to 16bar, so no problems with solvent welding when done correctly.

 

[pandos]

Does the toilet work, is there smell leaching from the pipework?

If not and it works, leave it alone.

There is a reason flexible pipes are used, it is easier to route, provides continuous bends so less likely to clog and will flex as the boat moves.

As @Boathook suggests, I think the wiring should be higher up the priority list.

It doesn't and it smells... And is a disaster waiting to happen with an in accessible stuck sea cock..with one hose clip...

 

[pandos]

Solvent welded grey PVC was my choice for all waste pipe work except the final connections to toilets, holding tank, change over valve and other fittings. Plenty of choice for fittings available including barbed connectors. Lots of information at the link below including chemical resistance. I also used it for the tank fill lines and pump out line.

PVC Pipe and Fittings | Metric | Inch | Wras PVCU

Systems available for pressures up to 16bar, so no problems with solvent welding when done correctly.

Looks like an excellent site/link. Many thanks, The clear pope work might be an interesting option... especially in the event of a blockage...

 

[Tranona]

Chuck it all out and fit a simple gravity system tek-tanks.com/sanitation-systems/holding-tank-plumbing-and-layouts/ gives some ideas of layouts

 

[pandos]

Chuck it all out and fit a simple gravity system tek-tanks.com/sanitation-systems/holding-tank-plumbing-and-layouts/ gives some ideas of layouts

That's a good resource, thanks . Just a few plastic elbows and vented loops and some new piping would probably go a long way towards a good robust system.

 

[Boater Sam]

Solvent welded grey PVC was my choice for all waste pipe work except the final connections to toilets, holding tank, change over valve and other fittings. Plenty of choice for fittings available including barbed connectors. Lots of information at the link below including chemical resistance. I also used it for the tank fill lines and pump out line.

PVC Pipe and Fittings | Metric | Inch | Wras PVCU

Systems available for pressures up to 16bar, so no problems with solvent welding when done correctly.

Precisely. Used at pressure with chemicals, hot water, mains water pressures and in swimming pools. Its not glue, it is a solvent that melts the pipe and fitting and amalgamates as a weld.

 

[ithet]

Having completed many thousands of pumped lavatory waste systems in houses factories and vans I have no worries about solvent weld coming apart, the clue is in the name - weld -.

I am sure you are more competent on plumbing than I. Somehow a comment of mine about batteries has got linked to listyd's. Some sort of glitch is the system?

 

[Bristolfashion]

Is it rated for positive/negative pressure as well as movement?

Oooh, a negative pressure movement sounds painful!