Problem with 450 Mid-Head Holding

[George Fletcher]

Peggy:I have a three year old 450 and I am having problems with the mid-head holding tank.A couple of months ago, I was unable to pump the tank either by suction, or by the macerator pump.I tied putting water under pressure into the tank and it was blocked solid.I finally had to lift the sole and get to the plumbing. It was obviously clogged betweeen the "tee" feeding the macerator and pump out hose.The tank was pumped using a tube into the hole for the pickup.I removed the hose between the "tee" and the pick up tube in the tank. The "tee" did not appear to be clogged, neither was the hose. The pick up tube also appeared open.I replaced the hose and the tank assuming the clog was dislodged. Wrong.The tank again filled and the pumpout is VERY slow. It will not pump at all through the macerator.I can get water to flow into the tank at a slow rate.I guess I now have a partial clog.Once again, I will go through the not so nice task of clearing the tube. I will replace it this time.Just wondering if the 450 plumbing suffers any strange problems I am unaware of?I plan to try and find a different style "tee" that doesn't have right angles, and replace the pickup tube in the tank with a larger diameter and a diagonal cut "business" end.Any comments or additonal suggestions. I only want to tackle this one time.Thanks.

 

[Peggie Hall/Head Mistress]

Has it ever occurred to you to check the tank vent

for a blockage? When the vent is blocked, any suction from the pumpout or the macerator pulls a vacuum that prevents any thing from being pulled out of the tank. The more you try to force water or anything else through the head discharge into the tank, the more the tank pressurizes, and the back pressure will prevent any water from pumped into it. The only reason you were able to empty the tank by inserting a tube into into the pumpout hose was because there was enough space between the outside of the tube and the inside of the pumpout hose to allow enough air to get into the tank to keep it from pulling a vacuum. Check your tank vents regularly for blockages! Blast the thru-hulls out with water EVERY time you pump out. If you'd done that in the first place you prob'ly could have saved yourself a lot of unnecessary work. And you'd have known to do that if you'd taken time to read the articles in the Reference Library on the home page of this forum...that's why they're there. Or if you'd just asked questions BEFORE you started blindly attacking the problem. That's why I'm here!

 

[George Fletcher]

The vent is "free and clear"

Peggy:I did in fact check the vent and it is free and clear.I also "blast" the tanks with water after pump.I will go ahead and "blindly" forge ahead with a repair on my own.I only asked a civil question as to whether or not there is any thing perculiar to the 450.Thank you for your help.

 

[Debra Blatnik]

Duct Tape on the hoses when you disconnect

This will contain the mess and the smell. Stuff rags in the fittings of the tank, Y valve, etc.You said you have a "T" between the macerator and the pump out line. I would replace this with a Y valve. I can't imagin this is causing any trouble.As far as the vent being free and clear, check to see that the vent hose does not have a dip in it forming a water trap. The vent line on my 37 did have such a water trap, causing the previous owner to only pump overboard. Re-routing the vent hose fixed the problem