You can tell from the sound of the pump when the impeller has picked up the last of the liquids, and in fact, from the sound and the pitch, when it is nearing that point beforehand. Listen and monitor the pumping while it is going on. In no case, should you allow the pump to run dry for more than a few seconds, for doing so leads to the impeller heating enough to break the epoxy bond from the hub. Then you have a spinning hub and no impeller activity. All of the suggestions given by others were excellent for troubleshooting your macerator problem. However, I will add another suggestion. I had my macerator pump run dry and ruin an impeller when a novice crew member turned on the switch and left it on accidentally. It was impossible to hear the macerator pump running from the fly bridge while underway. To prevent this from happening again, I added a very loud backup alarm to the circuit (less than $10 at an automotive store). Whenever the macerator is turned on, the noise draws attention and also prevents forgetting to turn off the pump. Since adding the switch, I have never had another impeller failure. Martin Veiner ____________________________________________________________ Need cash? Click to get a loan. http://thirdpartyoffers.juno.com/TGL2131/fc/PnY6rbt6qONNiDX9oYNqI2nO0tsFxHRHk WHSfrZg7dXbZG3qf7lIw/

that works in theory, in the real world it doesnt'... for instance, if your macerator is installe in the engine room, or in a generator room or anywhere noisy, it's not easy to hear it... since typically, one runs the macerator offshore, machinery will be running... and if you're single handling, again offshore, boat running, you dont' want to spend time away from the helm to listen to the macerator or watch then amp meter. On the otherhand, you can turn on the sealand and come back 10 minutes later to shut it down, no worries pascal ----- Original Message ----- From: <veiner@juno.com> To: <trawlers-and-trawlering@lists.samurai.com> Sent: Saturday, January 03, 2009 9:26 AM Subject: Re: T&T: Holding Tank > You can tell from the sound of the pump when the impeller has picked up > the > last of the liquids, and in fact, from the sound and the pitch, when it is > nearing that point beforehand. Listen and monitor the pumping while it is > going on.