Macerator not pumping in GS 232

[PaulinSeattle]

Does anyone have experience with the macerator not pumping the contents out of the tank in a Gulfstream 232?
I have an '04 GS 232, it had the original Sealand 960 series Sanipot, with the holding tank plumbed to a Y-valve for overboard discharge through the macerator pump or to a deck pumpout. When I have Y-valve to overboard discharge and run the macerator pump, i hear it running but it's not pumping anything. I went and replaced the macerator pump thinking the impeller had gone bad, and I replaced the original Sealand 960 sani-pot with a new Dometic 960 sani-pot (same model, just brand new). I filled the holding tank with water and hooked everything up, but still not pumping material out of the tank. With boat on trailer, I can feel air blowing out of the through-hull discharge.
I think disconnected the pickup 1 1/2" line at the sani-pot, and stuck a hose in there and sprayed it while running the macerator and the pumped picked up a prime and sucked out all the water i was spraying in with the hose. I hooked it back up to the sani-pot tank, and it wouldn't pump out. Anyone have any ideas for me to try?

 

[Hookup1]

Put a picture or two up of your tank and macerator. What is the manufacturer and model of the macerator.

Older GW used a in-tank Groco macerator. I switched to a Jabsco. It has the ability to "lift" material from the tank into the pump. This is a great pump but you can burn the impeller up if it doesn't prime quickly.


Beginning of season I have had problems with the pump impeller going dry. I disconnect discharge hose, install a 3' piece of vinyl hose, fill the hose with water and cycle the pump into a bucket. Then I see if the pump will empty the tank into the bucket. It's really important that all the hose connections are tightly sealed up - if there is an air leak the pump won't "lift". If this doesn't work check the impeller. I had one that looked good but took a set and wouldn't pump.

 

[seasick]

If the pump dose not support self priming, it has to be 'wet' (in standing water) to pump. That means that both the Y valve and the plumbing/pump have to have fluid in them. You issue could be as simple as the case where you installed the new pump and repositioned one of the hoses to a higher spot or inadvertently added a upward loop to a hose run ( between the tank and the Y valve.

Also, if the new pump is not rated for 'run dry' use, you may have fried the impeller

 

[DennisG01]

Is the vent line or hull fitting clogged?

 

[PaulinSeattle]

Is the vent line or hull fitting clogged?

I don't believe there's any clogs - i pulled the 1 1/2" pickup line off the holding tank and put a hose nozzle on spray up the hose and the macerator picked up the prime and pumped everything I sprayed up the hose. I then hooked the hose back up to the holding thank and once again it won't pull from the tank. I'm thinking the macerator is just too high above the holding tank to pull it. It's roughly 2' higher than the holding tank.

 

[PaulinSeattle]

If the pump dose not support self priming, it has to be 'wet' (in standing water) to pump. That means that both the Y valve and the plumbing/pump have to have fluid in them. You issue could be as simple as the case where you installed the new pump and repositioned one of the hoses to a higher spot or inadvertently added a upward loop to a hose run ( between the tank and the Y valve.

Also, if the new pump is not rated for 'run dry' use, you may have fried the impeller

Thanks seasick - the pump indicates it's self priming. I'm just thinking the pump is to far above the holding tank - it's roughly 2' higher than the hold tank (this is Grady's OEM design) - I simply replaced like parts for like parts.

 

[PaulinSeattle]

Put a picture or two up of your tank and macerator. What is the manufacturer and model of the macerator.

Older GW used a in-tank Groco macerator. I switched to a Jabsco. It has the ability to "lift" material from the tank into the pump. This is a great pump but you can burn the impeller up if it doesn't prime quickly.

View attachment 37536
Beginning of season I have had problems with the pump impeller going dry. I disconnect discharge hose, install a 3' piece of vinyl hose, fill the hose with water and cycle the pump into a bucket. Then I see if the pump will empty the tank into the bucket. It's really important that all the hose connections are tightly sealed up - if there is an air leak the pump won't "lift". If this doesn't work check the impeller. I had one that looked good but took a set and wouldn't pump.

I forget what model of macerator, but it was a Jabsco self-priming pump. I'll have to check model when I get home from work. I'm just thinking the design simply has the pump too high above the holding tank (pump is about 2' in elevation higher than holding tank).

 

[Hookup1]

I forget what model of macerator, but it was a Jabsco self-priming pump. I'll have to check model when I get home from work. I'm just thinking the design simply has the pump too high above the holding tank (pump is about 2' in elevation higher than holding tank).

I haver always had problems with these pumps lifting.

They quote: Jabsco macerator pumps are capable of self-priming and lifting waste water vertically. A typical Jabsco macerator pump can lift waste water up to 4-5 feet (1.2-1.5 meters) vertically. Hasn't been my experience.

Pumps above the tank will dry out and have a hard time priming. Use it more ofter to keep it wet. If it won't prime in 15 seconds stop or you will burn up the impeller. Even the ones they say won't.

inspect impeller and lube it clear lube (Harbor Freight Super Lube). Try to get it to pump. Make sure all the hose clamps are tight. I went to silicone hoses because this has been a pain! Silicone hoses seal better and are easier to take apart.