Scott

This started on another thread and I don't want to Hijack Ray

The Holding tank has been nothing but a hassle ever since we have owned the boat 98 380. The waste line comes out of the holding tank goes through a vented loop and straight to the tank. When the head was flushed the waste would start to go into the non vented tank and pressurize it causing the extra fluid to go out the vent on the loop and run down the side of the boat when we would pump out it would only take about 15 seconds to empty the tank making us believe that we were never empting the tank and that the lines were reversed or a pickup tube had broken off. I spent 8 hours with a jig saw and a lot of line changing to find out the damn tank was empty

The fix is a pain but well worth it and if Powerquest is still doing it this way shame on them, Hopefully they will read this and start installing the plumbing system the correct way. The small details do count!

Remove the vent line from the hard plastic loop (trap) and install the one way duckbill valve that they removed I replaced the whole loop (West Marine) T in another vent line and run this to the tank using a coat hanger or wire snake. You will have to make an access panel underneath the back seat. I matched the one used to access the fuel tank plumbing. Use a mirror and flashlight to confirm tank location before you cut. You will find a plugged vent on top of the tank remove the plug and install the new fitting and vent line. Make sure you clean the screen or remove it from the outside vent on the hull side it may be clogged from the tissue or whatever pushed through it.

We overnight a lot and use this (liquid only) in the middle of night or early morning. It sucked having a system that seemed to be full after a couple of flushes. Now we have been on vacation for a week and never had a smell or problem flushing and the pump out took the normal amount of time with the familiar vent sing when it was empty.

I can take pictures of the system if someone feels they have the same problem and wants to fix it.

BTW if you pull the driver’s side speaker you can see how the plumbing has been installed and it is easy to tell if the vent is only run to the loop (trap). I do not have tank access or pump access at this location only the plumbing to the deck fittings and vent.

Hope this helps someone and they don't have to experience the "old faithful" geyser of piss on a hot day when they remove the waste cap
I know this whole thing is gross and it ticks me off I had to go through this.

hp500efi

Scott, great advice and hopefully PQ can chime in regarding what they know so that others with newer boats maybe don't have to go through what you have.

Macklin

I believe they have changed the design....at least on the 340. Maybe BillR will chime in. I know he had to replace his macerator and he did it through the driver side coaming panel. I am pretty sure the holding tank piping is accessed from there as well.

BillR

If you look close, you can see how PQ runs the hoses on an '02 340. The waste line goes straight to the holding tank. The tank was a vacuflush, so it was always in a vacuum state. It did vent to the outside via a thru hull. But that was to evacuate air in holding tank after flushing. Duck bill valves were in macerator/pump out line to keep vacuum in tank.

Sounds like a different design than what you have.

Scott

Thats not even close to what I have. Mine is not a Vacuflush system.

I would hope that by now they have changed the plumbing on the standard head and that this post would help the folks that have the older system.

enticer

Scott..I believe what you have is exactly what they did before '01 or '02. My friend has a '99 and his is like yours I think. Now they are using the VHT-12 systems.....all in one. Mine a late '03. Some one drilled into the holding tank (vacuum area) in order to hold the cover on over the pressure switch and relay area and the unit never shut off. I located (hearing it) the leak after removing the speaker and panel. Filled the hole with silicone and reinstalled the cover and screw. Had to test the pressure switch and few times...seemed to have stuck closed. Now all works fine but only stays off for about 14 - 18 minutes then looses vacuum and brings the pump back on. Have to shut it off at night.......or it will drive you crazy

Goomba II

Scott, You just discribed the same problem I have. It,s a 99 380. Cut the hole to access the vent fitting on the waste tank and discovered a plug Went too the vent loop no check valve All sounds like you got the answer! My only question is it possible that there should be a check valve on the vent hose coming out of tank? It seems like the waste would come out when your getting on plane or the tank is pretty fool. Once again thanks for solution it,s ben driving my crazy and my wife keeps reminding of the time she got crap up yo her elbow taking the waste cap off!

Scott

GOOMBA,

Glad to hear this helped. I don't think a check valve will work with the tank vent since it has to let air in and out. But I did think about this and my next step to do this the right way will include a tank gauge.
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Goomba II

Scott. checked out that tank senser it seems like this is the perfect time to put this in. I like the idea of the external senser. Thanks again mite hook up with you at Ceder Point some day.