It's hard to get the macerator to start pumping out the holding tank on my H44. The only way that I have been able to do it is to close off the tank vent and then pressurize the tank through the deck pumpout fitting using a dinghy inflator while someone holds on the macerator switch. Once the macerator is primed it continues to pump. Hunter has given me a new pump, but that has not solved the problem. The boat is out of the water until the end of April and the tank has been flushed, so now is a good time to work on it. My best guess is that the macerator pickup tube is too close to the bottom of the tank and solids create too much of a barrier. Does anyone else have this problem? Better yet, does anyone know of a fix? The whole process is made more complicated because Hunter designed the tank level indicator to only register when the tank is more than 1/2 full. BTW: The tank does not seem to vent well since it develops a foul odor. I don't think enough oxygen gets to the tank, but I don't see any way to redo the plumbing. We only use KO as our holding tank treatment.
Macerator priming
- Thread starter Larry Jackel
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Macerator Pump Problem
These pumps are meant to be self priming. That means that they can suck liquid up into the pump from a lower level, ie your holding tank. I assume that you have a Jabsco 12V pump installed. The literature claims that this pump is capable of lifting liquid up to 4 feet. This is measured from the water level, possibly near the bottom of the tank, to the elevation of the pump impeller. First check that Hunter have not installed the pump too high - which is doubtful. I would say that the pump impellor (located well below the middle of the pump) should be no more than about 3'- 6" max. from the bottom of your holding tank. If this dimension is OK, I would very strongly suspect an air leak in the pipe connecting the suction side (bottom) of the pump to the holding tank. It could also be a worn impellor, but if you have installed a replacement pump, this is quite unlikely.
These pumps are meant to be self priming. That means that they can suck liquid up into the pump from a lower level, ie your holding tank. I assume that you have a Jabsco 12V pump installed. The literature claims that this pump is capable of lifting liquid up to 4 feet. This is measured from the water level, possibly near the bottom of the tank, to the elevation of the pump impeller. First check that Hunter have not installed the pump too high - which is doubtful. I would say that the pump impellor (located well below the middle of the pump) should be no more than about 3'- 6" max. from the bottom of your holding tank. If this dimension is OK, I would very strongly suspect an air leak in the pipe connecting the suction side (bottom) of the pump to the holding tank. It could also be a worn impellor, but if you have installed a replacement pump, this is quite unlikely.
Well this is a puzzle for sure....
I don't have this particular boat, I have a 40.5. However, the maserator should self-prime because it has a rubber vane-type pump mechanism. You should know that if this maserator is run dry for more than a minute or two without pumping, you can easily burn-up and destroy the impeller so that it will NEVER pump. I sense that this is a new boat since you say that Hunter has provided a replacement maserator pump. If in fact this is a new boat, I would start by examining all of the hose connections in the system. Sketch them all out. It may be that a hose was incorrectly routed at the factory. Does the tank empty properly using the deck pumpout? This fact could be a critical clue. On my boat, the tank pickup is connected directly to a TEE (no valves). One side of the TEE then goes to the deck pumpout and the other side of the TEE goes to the maserator. The output of the maserator goes directly to the overboard thru-hull thru a seacock. Since the deck pumpout must go to the tank pickup and also the inlet of the maserator, pressurizing the deck fitting with a dinghy pump would push air into the tank pickup and also to the input to the maserator. That doesn't seem like it should work or help at all since the maserator would try to pump air from the deck pumpout instead of pulling waste from the tank. If there was a valve that was blocking the maserator flow, then you would not be able to pump at all in the manner you describe. I will be watching this thread for a good answer from someone else.
I don't have this particular boat, I have a 40.5. However, the maserator should self-prime because it has a rubber vane-type pump mechanism. You should know that if this maserator is run dry for more than a minute or two without pumping, you can easily burn-up and destroy the impeller so that it will NEVER pump. I sense that this is a new boat since you say that Hunter has provided a replacement maserator pump. If in fact this is a new boat, I would start by examining all of the hose connections in the system. Sketch them all out. It may be that a hose was incorrectly routed at the factory. Does the tank empty properly using the deck pumpout? This fact could be a critical clue. On my boat, the tank pickup is connected directly to a TEE (no valves). One side of the TEE then goes to the deck pumpout and the other side of the TEE goes to the maserator. The output of the maserator goes directly to the overboard thru-hull thru a seacock. Since the deck pumpout must go to the tank pickup and also the inlet of the maserator, pressurizing the deck fitting with a dinghy pump would push air into the tank pickup and also to the input to the maserator. That doesn't seem like it should work or help at all since the maserator would try to pump air from the deck pumpout instead of pulling waste from the tank. If there was a valve that was blocking the maserator flow, then you would not be able to pump at all in the manner you describe. I will be watching this thread for a good answer from someone else.
Had similar problem
I had the same problem. I'd be surprised if you have the same issue but for what it's worth - Never could figure out why the macerator or it's new replacement wouldn't pump unil I removed the tank, removed the fittings and looked inside the tube to see the crack in my tank pickup tube at the joint it made with the top of the tank. I'm still not sure how the tube was afixed to the tank top but, how ever it was supposed to be attached, it failed at that almost invisible point.
I had the same problem. I'd be surprised if you have the same issue but for what it's worth - Never could figure out why the macerator or it's new replacement wouldn't pump unil I removed the tank, removed the fittings and looked inside the tube to see the crack in my tank pickup tube at the joint it made with the top of the tank. I'm still not sure how the tube was afixed to the tank top but, how ever it was supposed to be attached, it failed at that almost invisible point.
air leak
pump is self priming unless there is an air leak somewhere. My 37.5 had a leak in the welding of the aluminum holding tank. I temporarily repaired with strong electrical tape. replaced tank when we got home.. Check all hose connections from pick up to pump..
pump is self priming unless there is an air leak somewhere. My 37.5 had a leak in the welding of the aluminum holding tank. I temporarily repaired with strong electrical tape. replaced tank when we got home.. Check all hose connections from pick up to pump..
Hi Larry, I suspect your H44 is very close...
to our P42 that has a macerator pump between the holding tank and the through hull, all below the waterline. Our pump has always worked, but there have been times when it does not want to prime especially if the tank has little in it. What has worked for me is hold off using the pump until the tank is at least one half full. It has also helped to open the through hull and wait for a few minutes for raw water to enter and bypass the pump before turning it on, which seems to help with priming. Then other times I will have to turn the pump on for say five seconds, then off, then repeat a few times before it will prime. Seems odd, but whatever works. BTW, after I pump the tank contents through the deck fitting I always use city water pressure though the tank vent scupper to make sure it is clear of any blockage. I use a special nozzle fitting that covers the vent scupper so that I get good pressure through the vent line. I can tell right away if it's clear. Check out the P42 knowledge base under repairs, head winds, for the procedure that I use to keep our system running smoothly. It has been trouble free for five years since I fixed problems left over from the PO. Terry P.S. Our macerator will not prime or discharge if the pump out deck fitting is removed. It must be on and tight.
to our P42 that has a macerator pump between the holding tank and the through hull, all below the waterline. Our pump has always worked, but there have been times when it does not want to prime especially if the tank has little in it. What has worked for me is hold off using the pump until the tank is at least one half full. It has also helped to open the through hull and wait for a few minutes for raw water to enter and bypass the pump before turning it on, which seems to help with priming. Then other times I will have to turn the pump on for say five seconds, then off, then repeat a few times before it will prime. Seems odd, but whatever works. BTW, after I pump the tank contents through the deck fitting I always use city water pressure though the tank vent scupper to make sure it is clear of any blockage. I use a special nozzle fitting that covers the vent scupper so that I get good pressure through the vent line. I can tell right away if it's clear. Check out the P42 knowledge base under repairs, head winds, for the procedure that I use to keep our system running smoothly. It has been trouble free for five years since I fixed problems left over from the PO. Terry P.S. Our macerator will not prime or discharge if the pump out deck fitting is removed. It must be on and tight.
Definately...
...you are dealing with a leak on the suction side. Check the integrity of the system by pressurizing from the vent line and spraying soapy water over all the lines. The bubbles will locate your leak. If none is found externally then that only leaves the pick-up tube in the tank. Solids break down in the tank very quickly so a tube blockage is highly unlikely.
...you are dealing with a leak on the suction side. Check the integrity of the system by pressurizing from the vent line and spraying soapy water over all the lines. The bubbles will locate your leak. If none is found externally then that only leaves the pick-up tube in the tank. Solids break down in the tank very quickly so a tube blockage is highly unlikely.
I've never seen a holding tank with TWO pickups
But that is obviously possible. If I had known that there were two pickups, then the scenario would have made more sense to me. Thanks for that bit of info.
But that is obviously possible. If I had known that there were two pickups, then the scenario would have made more sense to me. Thanks for that bit of info.
You check the obvious?
If is smells, that means that the vents are most likely closed and need to be replaced. The obvious indication of this is small rust marks under the vents. The vents have a small steel screen that sometimes rust up and prevents air flow. As for the macerator not priming. Do you have fresh or salt water waste system? How about the plumming paste the maceretor? Have you checked the ball valve, and other pipes associated with it? Its amazing on how quickly the 3/4 inch pipes clog. BTW, does your boat have a for and aft head? How about 2 macerator pumps and 2 holding tanks or does it just have 1?
If is smells, that means that the vents are most likely closed and need to be replaced. The obvious indication of this is small rust marks under the vents. The vents have a small steel screen that sometimes rust up and prevents air flow. As for the macerator not priming. Do you have fresh or salt water waste system? How about the plumming paste the maceretor? Have you checked the ball valve, and other pipes associated with it? Its amazing on how quickly the 3/4 inch pipes clog. BTW, does your boat have a for and aft head? How about 2 macerator pumps and 2 holding tanks or does it just have 1?
44 Vent
Larry, I have 44 and have a very bad problem with the vent line clogging, the way it is routed there is a place where the height of the line drops down below the level of the tank. So if I heel to Port with liquid in the tank, it ends up in the vent line.
Larry, I have 44 and have a very bad problem with the vent line clogging, the way it is routed there is a place where the height of the line drops down below the level of the tank. So if I heel to Port with liquid in the tank, it ends up in the vent line.
There's a way to fix that, Gary..
When the vent fitting on the tank is on the outboard side of the tank, waste runs into the line to clug it up and spill out the vent thru-hull. Moving the vent fitting on the tank to the inboard (toward the centerline, away from the hull) side of the tank--on the top, the end or a side--prevents that from happening...because when a tank fitting is inboard, waste in the tank runs aways from it when heeled to one side...it would have to run uphill to get into the line when heeled to the other side. Putting the inlet fitting from the toilet on an inboard side of the tank also prevents waste in the tank from running back toward the toilet. When replacing a tank, the solution is to specify the vent and inlet fittings on inboard suraces...but--thanks to a li'l doodad called the "uniseal" http://www.aussieglobe.com/uniseal1.htm --moving a fitting isn't that hard to do either. A threaded plug well wrapped in teflon tape will seal the existing fitting.
When the vent fitting on the tank is on the outboard side of the tank, waste runs into the line to clug it up and spill out the vent thru-hull. Moving the vent fitting on the tank to the inboard (toward the centerline, away from the hull) side of the tank--on the top, the end or a side--prevents that from happening...because when a tank fitting is inboard, waste in the tank runs aways from it when heeled to one side...it would have to run uphill to get into the line when heeled to the other side. Putting the inlet fitting from the toilet on an inboard side of the tank also prevents waste in the tank from running back toward the toilet. When replacing a tank, the solution is to specify the vent and inlet fittings on inboard suraces...but--thanks to a li'l doodad called the "uniseal" http://www.aussieglobe.com/uniseal1.htm --moving a fitting isn't that hard to do either. A threaded plug well wrapped in teflon tape will seal the existing fitting.
advise me
Larry, I did not have the problem with our 44, which does not mean I am not going to have it, so please let me know what you find.
Larry, I did not have the problem with our 44, which does not mean I am not going to have it, so please let me know what you find.
Vidazzled and Grant: Checked out the vent line
I checked out the vent line today. As Grant mentioned, where the line led aft from the holding tank and before it rose to the vent it sagged about 4 inches. Futhermore, it was routed through a hole in a bulkhead below the large pumpout hose. The net result is that it formed a nice water trap. This afternoon I removed the vent line from the tank, rerouted it above the pumpout hose through the bulkhead, reconnected it to the tank, and suspended it with cable ties along the horizontal run to remove the sag. Now with gentle normal rolling and pitching at our mooring, if there is any liquid in the line, it should drain back into the tank. I considered Peggie's suggestion of moving the place where the line connects to the tank to a point further in board. Right now the line connects about about half way across the tank. Moving the connection point looked like a risky task, so I will first see if my re-routing of the vent line at least helps with the foul smells. I am also speculating that lack of oxygen caused by a blocked vent line may have prevented a breakdown of solids in the tank causing my macerator problems. In two weeks I will de-winterize the boat and start flowing water through the holding tank and see if the macerator is happy when it just has to prime on clean water.
I checked out the vent line today. As Grant mentioned, where the line led aft from the holding tank and before it rose to the vent it sagged about 4 inches. Futhermore, it was routed through a hole in a bulkhead below the large pumpout hose. The net result is that it formed a nice water trap. This afternoon I removed the vent line from the tank, rerouted it above the pumpout hose through the bulkhead, reconnected it to the tank, and suspended it with cable ties along the horizontal run to remove the sag. Now with gentle normal rolling and pitching at our mooring, if there is any liquid in the line, it should drain back into the tank. I considered Peggie's suggestion of moving the place where the line connects to the tank to a point further in board. Right now the line connects about about half way across the tank. Moving the connection point looked like a risky task, so I will first see if my re-routing of the vent line at least helps with the foul smells. I am also speculating that lack of oxygen caused by a blocked vent line may have prevented a breakdown of solids in the tank causing my macerator problems. In two weeks I will de-winterize the boat and start flowing water through the holding tank and see if the macerator is happy when it just has to prime on clean water.
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