I have a Hunter 42 Passage. I have read frequently that the aluminum holding tank fails on this vessel. Some questions: The tank apparently needs to be in a vacuum state when operating the Macerator or pumping the tank out. (Says so in the Macerator manual.) Since the tank's vent line must only work in the exhaust mode only, then while pumping out, the tank must be compressed, literally sucked in. That would certainly be a cause for the aluminum tank failure. After the pumping, how does the tank reform itself. How does air get in there so the tank can reform itself. Or at least so the pressure can equalize.
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Dennis Thomas
Re-read your manual
Just can't be. A pump out can only work if the tank is vented. If not vented it will draw air through the head. Try putting your finger over the vent hole during a pump out. You should feel the suction. If you block the vent long enough it will cause the suction to drain your toilet bowl and draw air in past the joker valve.
Just can't be. A pump out can only work if the tank is vented. If not vented it will draw air through the head. Try putting your finger over the vent hole during a pump out. You should feel the suction. If you block the vent long enough it will cause the suction to drain your toilet bowl and draw air in past the joker valve.
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Peggie Hall/HeadMistress
No...not quite
I think you misread the macerator manual. If the tank were in "a vacuum state" it would be impossible to pump it out or dump it...And an exceptionally strong pumpout could destroy a tank if it pulled a vacuum. A vent line cannot BE in "exhaust mode" only unless there's a one way valve in it--which there definitely should NOT be! A vent line has to be open so that air can travel both directions. In fact, one of the first clues that a holding tank vent line has a blockage is an inability to empty the tank, or back pressure when the toilet is flushed. So it's an interesting theory--although one that indicates you need just a wee bit better understanding of the laws of physics at work in a holding tank (gas tank, water tank or thermos bottle), but that's not the reason why aluminum tanks fail. They fail because urine is so corrosive that it makes salt seem benign by comparison....they corrode, they aren't "beaten to death." For a better understanding of how the system works, I suggest you read the articles in the Reference Library in the Head Mistress forum.
I think you misread the macerator manual. If the tank were in "a vacuum state" it would be impossible to pump it out or dump it...And an exceptionally strong pumpout could destroy a tank if it pulled a vacuum. A vent line cannot BE in "exhaust mode" only unless there's a one way valve in it--which there definitely should NOT be! A vent line has to be open so that air can travel both directions. In fact, one of the first clues that a holding tank vent line has a blockage is an inability to empty the tank, or back pressure when the toilet is flushed. So it's an interesting theory--although one that indicates you need just a wee bit better understanding of the laws of physics at work in a holding tank (gas tank, water tank or thermos bottle), but that's not the reason why aluminum tanks fail. They fail because urine is so corrosive that it makes salt seem benign by comparison....they corrode, they aren't "beaten to death." For a better understanding of how the system works, I suggest you read the articles in the Reference Library in the Head Mistress forum.
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Bradley Cavedo
Tank is OK
We have the P42 also. Think of the macerator as being on the bottom of the tank and the vent hose on the top. As the macerator draws down fluid from the bottom, air replaces the fluid from the top. The deck pump out plate is also on the bottom of the tank because if joins the pipe that leads to the macerator. I have inspected my tank and it is a very good, solid product and well installed. I doubt it will ever fail, but we will see.
We have the P42 also. Think of the macerator as being on the bottom of the tank and the vent hose on the top. As the macerator draws down fluid from the bottom, air replaces the fluid from the top. The deck pump out plate is also on the bottom of the tank because if joins the pipe that leads to the macerator. I have inspected my tank and it is a very good, solid product and well installed. I doubt it will ever fail, but we will see.
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jolie
Vacuum
I swear I heard a vacuum when I unscrewed the holding tank pump out cap. But when I flushed the tank with water, the vent was open and water overflow shot out. Is it possible I have a blocked vent only one way??? It sure seemed like the macerator sounded diferently and less straining when pumped with the pump-out cap removed. Any ideas how to check if the vent is allowing two way air flow???
I swear I heard a vacuum when I unscrewed the holding tank pump out cap. But when I flushed the tank with water, the vent was open and water overflow shot out. Is it possible I have a blocked vent only one way??? It sure seemed like the macerator sounded diferently and less straining when pumped with the pump-out cap removed. Any ideas how to check if the vent is allowing two way air flow???
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Peggie Hall/HeadMistress
No way you can have a one-way vent block...
.If the tank is pressurizing, I suspect that you have a partial blockage--possibly a kink, or something has gotten into it. You may have cleared it when you filled the tank to overflowing with water. Fill it with water again, and this time be standing close enough to the vent while it's being pumped out (not during a macerator dump-out, 'cuz a pumpout has much stronger suction than a macerator)...if the vent's ok, you should be able to hear air going into it as the level in the tank drops...and it should get noisier when the tank is empty. In case the vent isn't open sufficiently, put someone else next to the tank to watch the level (if it's plastic) or (if aluminum) the sides of the tank to make sure the pumpout isn't trying to collapse the tank. In a metal tank, a small amount of flexing as the tank empties is normal...watch for signs of a real strain. If the system doesn't have a y-valve, only a wye or tee fitting, in the pumpout line, your macerator WILL sound different with the deck fitting cap off...because it's mostly sucking air instead of the tank contents. The deck fitting has be closed, or you can't empty the tank. And that's another thing to check: You know how much the tank holds...after you think you've emptied it, put water back into it from a container that will allow you know how much you're putting in the tank before it overflows. If it's not close, the tank isn't emptying.
.If the tank is pressurizing, I suspect that you have a partial blockage--possibly a kink, or something has gotten into it. You may have cleared it when you filled the tank to overflowing with water. Fill it with water again, and this time be standing close enough to the vent while it's being pumped out (not during a macerator dump-out, 'cuz a pumpout has much stronger suction than a macerator)...if the vent's ok, you should be able to hear air going into it as the level in the tank drops...and it should get noisier when the tank is empty. In case the vent isn't open sufficiently, put someone else next to the tank to watch the level (if it's plastic) or (if aluminum) the sides of the tank to make sure the pumpout isn't trying to collapse the tank. In a metal tank, a small amount of flexing as the tank empties is normal...watch for signs of a real strain. If the system doesn't have a y-valve, only a wye or tee fitting, in the pumpout line, your macerator WILL sound different with the deck fitting cap off...because it's mostly sucking air instead of the tank contents. The deck fitting has be closed, or you can't empty the tank. And that's another thing to check: You know how much the tank holds...after you think you've emptied it, put water back into it from a container that will allow you know how much you're putting in the tank before it overflows. If it's not close, the tank isn't emptying.
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Phil
Holding tank failure
I have a '94 P42 which I purchased "used" in Feb 2000. The aluminum holding tank was badly perforated, but I didn't discover that until a month later and was trying to locate the source of the nasty "head" odor. The replacement tank from HUNTER is worth $275, but still made of aluminium. I had a stainless steel tank fabricated (in Ensenada at the time) and it works fine.... although there was still a detectable head odor which was likely caused by the hoses. No way that the tank is under vacuum when the macerator is run. The tank is vented off the top and the macerator draws off the bottom.
I have a '94 P42 which I purchased "used" in Feb 2000. The aluminum holding tank was badly perforated, but I didn't discover that until a month later and was trying to locate the source of the nasty "head" odor. The replacement tank from HUNTER is worth $275, but still made of aluminium. I had a stainless steel tank fabricated (in Ensenada at the time) and it works fine.... although there was still a detectable head odor which was likely caused by the hoses. No way that the tank is under vacuum when the macerator is run. The tank is vented off the top and the macerator draws off the bottom.
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