[HNS]

It seems I have a clog in my air vent to my waste tank. I was able to macerate discharge but could not pump out. Does anyone know where this filter is located? Thanks....

[Uhehner]

You did not specify what size boat you have so others can respond but I would say look in the manual or call Tiara. Typically the small hose coming out of the top of the tank is the vent hose and it goes up the side of the boat to the outside overboard vent making an anti-siphon loop at the top.. This is a direct and short run. There may be an in-line filter behind an access cover. The pumpout hose is much larger and connects from the tank bottom to the deck pumpout. I doubt if there are any valves in the line to the deck pumpout. Are you trying to use the macerator pump to pump the holding tank? Then I think you need to check the plumbing diagram in the manual and get the correct valve line-up. If you are using the macerator to pump out and suspect a clogged vent, just open the deck pumpout to vent the tank.
The following is a comment I wrote previously:

Check the overboard vent. I had trouble with the holding tank collaping in on itself because the pumpout suction was great but the vent was plugged. The nasty stuff in the holding tank corroded the vent screen shut. I removed the screens with a dental pick and have not had a problem since. Those screens are necessary only on the fuel tanks. They also serve to keep bugs out so check them now and then. I also had an engine stalling problem once caused by the fuel tank vent which I replaced and cured the problem. If your water tank or fuel tank fill keeps backing up as you add water or fuel, check the vent. As you put volume in, air has to come out. Listen for a hissing sound when you crack the cap, that should give you a clue. There should never be a pressure or a vacuum in your tanks. Capt. George

[momentum]

Is the y valve in pumpout position?

[momentum]

I forgot to mention check hose connections , my 4000 had a loose hose behind the pumpout thru hull . It would not allow vacuum to lift the waste . Dont ask how I found it.

[HNS]

I forgot to mention my boat is a 38 open. Curious, how did you find it? .....and yes the Y valve is in the pumpout position. And where is the thru hull for the 40. I'm guessing I would see it when I pull back my helm station. Did you find the filter behind the thru hull?

[momentum]

My charcoal filter is mounted on the engine room wall (bulkhead) on the starboard side .I found the leak on the back side of the thruhull fitting when the waste forced is way all the way up the line and out . My tank tender operates with a few issues . The waste leaked into the midcabin . We now know how to maintain the system . Tough way to learn ! The pumpout is on the starboard midship on the walk around .

[HNS]

What size/year is your Tiara??

[momentum]

My boat is a 94 40 express .