Trionic Premium Holding Tanks

[peghall]

are you saying that you dont approve of such fitting?

That is what I'm saying. The "pressure relief valve" that Trionic sells is a device that SeaLand came up with and markets...it's designed to prevent any air from escaping, only allows air INTO the tank to prevent a strong pumpout from creating enough suction to implode a tank in the event that the tank vent line becomes blocked. However, if the vent line does become blocked, the tank is likely to become pressurized (the pressure relief valve doesn't prevent that)...creating a geyser when the deck pumpout fitting is opened that can eliminate the need to pump out while creating a need to wash off both the boat and the hapless crew who opened the fitting.. So the "pressure relief valve" is really of little value unless you count entertainment.

Google "Sealand pressure relief valve" for details and photos.

[endoftheroad]

peghall,
once again thanks for the sound help on this forum.

endoftheroad

[Blue Crab]

Not even as a gift, Peg? Come on.

The object is to keep poop out of the water inshore.

The dry head way is simple, if a little on the crude/unpleasant side. Takes far less space, and is as simple as Forrest Gump. The most you can spill is "sterile" urine.

The wet head? Well, you're the expert.

But from a small boat pov, and the continuing maintenance necessity, the wet head = more space, hassle, and expense.

As a personal reminder to me, I saw the scene described above on a pumpout. I won't describe it as a courtesy to our kindler, gentler readers.

[jgbrown]

Originally Posted by peghall

are you saying that you dont approve of such fitting?

That is what I'm saying. The "pressure relief valve" that Trionic sells is a device that SeaLand came up with and markets...it's designed to prevent any air from escaping, only allows air INTO the tank to prevent a strong pumpout from creating enough suction to implode a tank in the event that the tank vent line becomes blocked. However, if the vent line does become blocked, the tank is likely to become pressurized (the pressure valve doesn't prevent that)...creating a geyser when the deck pumpout fitting is opened that can eliminate the need to pump out while creating a need to wash off both the boat and the hapless crew who opened the fitting.. So the "pressure relief valve" is really of little value unless you count entertainment.

Google "Sealand pressure relief valve" for details and photos.

Colour me confused. We usually install both! A vent(using sealand vent fitting) and also the one way valve.
I don't think it's supposed to be only that one way vent, the sealand manuals show both?

[peghall]

Apparently you missed a key phrase in my comment...".it's designed to prevent any air from escaping, only allows air INTO the tank to prevent a strong pumpout from creating enough suction to implode a tank in the event that the tank vent line becomes blocked. However, if the vent line does become blocked...

However, SeaLand/Dometic does offer a tank system that has ONLY a pressure relief valve, no other vent, for use with their VacuFlush toilet...it can't be vented because the holding tank doubles as the vacuum tank. Their "Sailvac" tank is an example:

products - Dometic

Worst idea on the planet IMO.

Bye, y'all...till the next time I need a "fix." Hope to see some of you in Melbourne (the one in FL)!

Peggie

[jgbrown]

Originally Posted by peghall

Apparently you missed a key phrase in my comment...".it's designed to prevent any air from escaping, only allows air INTO the tank to prevent a strong pumpout from creating enough suction to implode a tank in the event that the tank vent line becomes blocked. However, if the vent line does become blocked...

However, SeaLand/Dometic does offer a tank system that has ONLY a pressure relief valve, no other vent, for use with their VacuFlush toilet...it can't be vented because the holding tank doubles as the vacuum tank. Their "Sailvac" tank is an example:

products - Dometic

Worst idea on the planet IMO.

Bye, y'all...till the next time I need a "fix." Hope to see some of you in Melbourne (the one in FL)!

Peggie

I did miss that, sorry! We only install them as a safety(and I think, a rather important one). Never seen one of those all in one tanks, hope I never do. It's bad enough servicing the normal ones with all the usual neglect. Had one explode this month. Over filled so badly they plugged the vent after filling the filter with sewage, then kept pooping until they blew a fitting off the tank, then kept filling the bilge until the smell got bad...