Holding tank Pump

[Chrissyking]

Hi
Can anyone help me with a really annoying problem I have with my holding tank. It just will not pump out. Have bought 2 new kits, so I know there is no electrical fault. New pump is sound. When I get tank out fill it with water it pumps out perfectly. The minute it goes back inside it won't pump out. What am I doing wrong ? Desperate
Chrissy

[Chrissyking]

Now the impeller has just snapped on new pump ...getting really angry now !!!!!

[peghall]

Originally Posted by Chrissyking

Now the impeller has just snapped on new pump ...getting really angry now !!!!!

I'm guessing a blocked tank vent is the source of your woes, most likely the vent thru-hull. When the tank is out, the vent fitting on the tank is open, providing the necessary source of air to prevent your macerator pump from pulling a vacuum that won't allow anything to be pumped out. When you put it back, the pump pulls a vaccuum. The impeller snapped because running dry "fried' it.

Spring is when the mud daubers love to build their mud nests in any opening they can find...or, the vent thru-hull--and maybe the vent LINE too--may just be clogged with waste that's spilled into it when the boat heels. Cleaning out the thruu-hull--and maybe the vent line too--should solve your problem.

The good news: at least you're only dealing with water till you've solved the problem...not a tankful of waste!

[antoha]

Maybe a bad check valve? Sometimes they are called duckbill valves. Your pump would be just spinning the stuff around without a sense of direction. On mine, there are 2, in the same direction, before and after pump - so the action is 2 stage: suck it in - push it out.


Sent from my iPhone using Cruisers Sailing Forum

[DeepFrz]

What kind of pump are you using. I don't think you want a pump with an impeller on the output of a black water tank.

Something like this may be better but others with more experience might have a better suggestion.
Whale Marine - Products

[Emmalina]

All the macerator pumps I have used are impellor driven but have a metal macerator before they pump ! They claim to lift 5 feet but I have always had to drop them below the tank level to get good output

[DeepFrz]

Yes, metal that wont break when you are pumping water. Some home waste water pumps are cast iron impellers.

[GordMay]

Greetings and welcome aboard the CF, Chrissy.

[antoha]

Do you have photos of your pump, or brand name? Mine is by SeaLand, and I don't believe it has an impeller - bellows action is used instead. $275 or so at defender.


Sent from my iPhone using Cruisers Sailing Forum

[Chrissyking]

Hi guys. All fixed. Replaced all pick up pipes, including inside solid. Somebody had previously botched some home domestic plumbing pipes :/. Plus new service kit for pump. Many thanks to all of you for your help and suggestions and yes thank god it was only water in there
Regards
Chrissy x

[Chrissyking]

Thanks Gord may for welcome. Have a good weekend. 👍