356 forward head holding tanks issue

[Barb]

Hello! I've recently discovered that the forward head on our 2002 Carver 356 aft cabin appears to have 2 small holding tanks. the tank closest to the bow does not empty with a pumpout.. there appears to be a valve separating the tanks but the valve won't move and I'm afraid to force it. I'm assuming if the valve could be opened the tank would pump out? Assuming I'm on the right track in the first place....
Any help out there? thanks so much.

Barb
Fearless

[km1125]

I'm curious to see what you find out. A friend of mine has a similar 356 and he was always complaining that he had to pump out constantly because he only had an 18 gal tank, which I thought was unusually small. I wonder if they used two 18 gal tanks in these?

[bud37]

Welcome to the forum....according to the parts listing for your boat it shows that there are two 18 gal waste tanks , one for each head.....how many deck pump out fittings do you have ??
Maybe there will be something in the owners manual if you have it.

https://carveryachts.blob.core.windows. ... ......page 17.1

[buster53]

That's what my 356 has...two 18 gal holding tanks, one for each head. Two pump outs, both on the starboard side.

[mjk1040]

Barb, there should be no valves and no holding tanks next to each other, unless you have a gray water holding tank or someone has added a tank. Make sure your tank vent is not plugged. This alone will keep a holding tank from pumping out. No air in when pumping out means no pumping out. A picture of what you are looking at and describing would certainly help.

[Barb]

Thanks! I will grab a pic this weekend. The aft head has it's own holding tanking under the berth in the back. There is definitely something odd with forward head.

[km1125]

Is it possible you have an overboard discharge for that system? We don't use them around here, so no one I know has them.

[tomschauer]

My 355 has the overboard discharge option. It has y valves at both holding tanks and a discharge macerator pump, but not a third holding tank.
It may be a greywater tank, or someone added an extra blackwater tank.
Send us some pics Barb.