Using PVC in exhaust loop

[piripucha]

After reading the threads regarding the installation of a new Norpro generators, I decided to overhaul my generator room. I am going to move the NL generator aft and relocate the aqualift from the shelf beneath the stairs that go down to the galley. The boat is a 1978 58 YF. I had a water injestion problem last year, that I belive was caused by the position of the aqualift. What I would like to know is if I can use PVC tubing schedule 40, to fabricate the loop for the exhaust hose that goes from the exit of the aqualift to the discharge port.
Thanks in advance.

 

[Canuck Dennis]

I have done similar for two exhausts, use Schedule 80 PVC, it has a higher rating than standard,... 135 f, also install high temp alarm on exhaust prior to the aqualift. I have had no problems so far, installation was in 1995.

 

[Pascal]

the water ingestion may not be on the exhaust side, but on the raw water side. make sure you have a vented loop between the raw water pump and the exhaust manifold...

most install insturctions state that the muffler must be on teh floor, however on many Hatt MY incl my own it was located higher up near the exhaust thru hull. i moved mine...

 

[rsmith]

After reading the threads regarding the installation of a new Norpro generators, I decided to overhaul my generator room. I am going to move the NL generator aft and relocate the aqualift from the shelf beneath the stairs that go down to the galley. The boat is a 1978 58 YF. I had a water injestion problem last year, that I belive was caused by the position of the aqualift. What I would like to know is if I can use PVC tubing schedule 40, to fabricate the loop for the exhaust hose that goes from the exit of the aqualift to the discharge port.
Thanks in advance.

If your going to do it its sch 80 CPVC that is the higher temp rating but as the schedule of the pipe goes up the effective ID is reduced.why take the chance with pvc when you can get fiberglass pipe?

 

[bobk]

The melting point of PVC is independant of the schedule. Remember it melts! Fiberglass or rubber does not. I'd only use PVC as an emergency repair, not as part of a deliberate modification. The use temperature rating is under pressure in a water application so thicker resists pressure and temperature better but has little to do with what you are contemplating..

I wonder how a surveyor or insurance company would view PVC in an exhaust system?

Bob

 

[SKYCHENEY]

Use fiberglass tube. It can be purchased in straight or curved sections and can be glassed together as needed to get the configuration that you need.

Also, as Pascal stated, you need to have a vacuum break on the intake side. Add one if you don't already have one there.

 

[captddis]

Use fiberglass tube. It can be purchased in straight or curved sections and can be glassed together as needed to get the configuration that you need.

Also, as Pascal stated, you need to have a vacuum break on the intake side. Add one if you don't already have one there.

You want the siphon break right before the discharge into the exhaust elbow. Putting it on the inlet side of the pump will cause suction problems. The valve on the vented loop closes with pressure on it.

 

[rsmith]

The melting point of PVC is independant of the schedule. Remember it melts! Fiberglass or rubber does not. I'd only use PVC as an emergency repair, not as part of a deliberate modification. The use temperature rating is under pressure in a water application so thicker resists pressure and temperature better but has little to do with what you are contemplating..

I wonder how a surveyor or insurance company would view PVC in an exhaust system?

Bob

Exactly but even if it dosent melt given the temps it will become brittle and could crack. I redid one of my baths in the house pulled down a piece of
3"pvc dropped it on the floor from ladder heigth the thing shattered like a piece of china.That pipe was covered in the ceiling not exposed to uv and only 10years old.

 

[SKYCHENEY]

You want the siphon break right before the discharge into the exhaust elbow. Putting it on the inlet side of the pump will cause suction problems. The valve on the vented loop closes with pressure on it.

Sorry, I posted that wrong. It should look like this:

 

[piripucha]

Thanks you all for your input. After the water injestion problem that I had, I put a anti-siphon valve betwen the raw water pump and the HE intake, acording to the Northern lights installation manual. What I believe caused the injestion issue was that I had problems starting the generator, it suck up the air filter element wich stuck on the air intake manifold. This has happened to me in two ocassions. I belive it could be caused by the fuel oil, which here in Venezuela has a high content of sulfur, wich breaks up the sponge like air filter element. Going back to the original question I am going to make the loop from fiberglas tubbing. Thanks again.