Macerator Acting Strangely

[Homer Shannon]

I put a Jabsco macerator and all new plumbing in my B29.9 before the beginning of the 2012 sailing season. The plumbing is a bit different in that I removed the toilet to sea connection - the toilet now goes directly to the tank. The tank is connected to the deck plate and the macerator with T fitting and the macerator, which is mounted just above the water line, goes directly to a through hull that is always kept closed unless we are discharging.

This arrangement has worked perfectly though we have probably only run the macerator a dozen or so times in the two seasons we have had it installed. We are careful with our paper and do not put any other items in the toilet.

This past weekend we I wanted to drain the holding tank while we were off shore. I opened the seacock on the through hull and held the button switch for the macerator. The pump made its normal priming sounds then slowed to a crawl as though it were clogged or the through hull was closed. I closed the valve and let the system 'rest' to see if whatever was clogging the system would soften and allow the system to operate again. I tried this several times over a few hours with no effect.

I have no reason to believe there is anything in the tank, other than what should be there - and that is mostly water. Last fall, while winterizing the boat I had a similar incident: The tank had been pumped before hauling. I put about a half gallon of septic anti-freeze in the system, then ran the pump to pull some of the anti-freeze up into the pump. The pump behaved exactly as it is now behaving. The problem last fall was that one of the boat stands was directly over the through hull, completely blocking it. I moved the stand and finished that pump out without incident.

This makes me think that my current problem may not be a clog on the intake side, but a blockage on the outlet side. Any suggestions on the best way to inspect and correct this problem. I've read that running the motor backwards (which seemed like it might be a good idea) is not recommended.

[HopCar]

I think the first thing I'd do is pull the discharge hose off the pump, lower the hose below the waterline, and see if water flows into the boat. That will tell you if the discharge hose is blocked. If it is blocked the water pressure might clear the hose.

If water doesn't come out of the hose, remove the hose from the seacock. If water still doesn't come into the boat, clear the seacock. If water does come in, clear or replace the hose.
Depending on your seacock type, your seacock might still be closed. I've seen Marlon seacocks with broken stems. This allows the handle to move like normal but the ball doesn't move. This is pretty unlikely but if the discharge is blocked, it's one possibility.

I hope your problem is on the discharge side. If it's on the intake side, things are going to get messy!

[chrisjs]

When we had a similar issue it was the result of barnacles in the outlet. Combined with ground up TP etc. just a few critters can provide a significant barrier to discharge. Suggest you swim down and take a screw driver with you (preferably with the outlet valve in the closed position!!!).

One other (more difficult) problem might be a blocked inlet air vent resulting in a tank vacuum. Might be blocked by wasps etc. at deck level or blocked with dried poop at the tank end.

[Homer Shannon]

Thank you for your comments. The sea cock is a well maintained traditional cone-type valve, so there is no chance it is in the wrong position or not operating properly. The is a possibility of barnacles clogging out outlet, though they would have to be between the outer surface of the thru hull and the valve because the valve is always closed. I've cleaned barnacles out of through hulls after every season, but I've never had to remove enough that they were fully clogging the associate drain. The galley sink and two cockpit drains with identical thru hulls, seacocks and hose materials are left open all season and have never clogged from sea growth. Still, I'll check it... getting kind of cold here (New England) for jumping in!

The vent was just checked about a month ago and was fine at that time. Also, I have no problems with flushing the toilet and the macerator worked perfectly about a week ago. I'll, check the vent again, but I do not think that is the problem.

I think an easy check would be to feel the hose on the output side of the pump and see if that is expanding as the pump tries to work. If it is - I guess I have a clog on that side. If it does not - then I'm going to have to get dirty.

[HopCar]

" Still, I'll check it... getting kind of cold here (New England) for jumping in!"
That's what I had in mind when I suggested you remove the hose to see how much water comes in. You can even clean the thru-hull from inside. It will probably be a 1" seacock and thru-hull as that's the size of hose the Jabsco macerator discharge fits. Close the seacock, pull the hose, open the seacock and shove a dowel down through the seacock and out through the thru-hull. Close the seacock and reattach the hose. It shouldn't take more than about thirty seconds to do this.
You'll get wet, but not as wet and cold as jumping into the water.

[Homer Shannon]

Due to schedule issues with the pump out boats in our area, I never did get my tank pumped before the boat came home for the winter. When the boat was hauled, it was pressure washed so I never saw the condition of the macerator through hull. When the boat was in my yard, I tried the macerator and it worked perfectly. I assumed that barnacles in the through hull had been the issue.

This morning, using a bucket and an assistant, I pumped the tank dry using the macerator and a bucket below the through hull. (Stinky!) After draining the tank, I used a hose to rinse it out as I want to replace the tank with an HDPE tank; the current tank is a glassed wooden box. I put a few gallons of water in the tank several times and pumped them out of the boat using the macerator. Then the pump started behaving exactly as it had before: it runs slowly, winds down and stops as if the through hull were closed.

In this case, I KNOW there are no barnacles in the through hull and no extra paper that could clog the pump – it's just water! Any ideas as to what could be going on? I am completely buffaloed.

[Hudson Force]

Likely, there is a rubber cap at the center end of the macerator pump that can be easily pulled off. Under this cap the center axel of the pump is exposed with a slot to accomodate a screw driver. You can manually turn this in a clockwise direction with a screw driver to rotate the macerator blades and possibly clear whatever is blocking the pump. 'good luck!

[Homer Shannon]

Any thoughts as to why it would appear to clog, then unclog itself, then get glogged again when there was nothing to pump but water? And, it was running perfectly before it began acting clogged again. Nothing but water was put in the tank. I had the access port open and was able to see that there was nothing in the tank but water.

[Hudson Force]

I have found wads of hair or, worse yet, dental floss wrapped around the shaft of my pump and jamming it while nothing else was in the tank. Have you had any guests that are not aware of the sensitivity of a marine head?

[Homer Shannon]

No, no guests and my wife does not even put paper in the toilet (I do). She puts it in the trash basket. There is nothing in the tank that should not be there, the hoses are all new and, right now, there is only water in the tank. Mysterious.

[sabray]

Pump is kaput. Burned out brushes , bearings or really bad electrical splice.

[Captain Bill]

Originally Posted by CaptForce

I have found wads of hair or, worse yet, dental floss wrapped around the shaft of my pump and jamming it while nothing else was in the tank. Have you had any guests that are not aware of the sensitivity of a marine head?

+1 on the hair. My shower pump acted exactly as described and it was caused by hair on the macerator blades. I decided I did not need the blade on the shower pump and removed them. Problem solved. If you have a macerating head, do you really need the chopper on the overboard pump?

[sailr69]

when the slow down happens, does it blow a fuse? it should if the pump is good and there is a blockage. if the pump does not blow a fuse , my guess is the pump went bad

[Homer Shannon]

No fuses have been blown. I don't think the motor has failed as it has done this twice before now and both times it somehow recovers and the motor runs strongly. Forget about the hair - we don't have an on board shower. I don't know if we have a macerating head. It's just a basic head, Raritan, I think.

When I emptied the tank earlier, there was nothing but disgusting brown water. You could have passed it through a sieve and not gotten a tablespoon of solid material. It's just liquids.

[Stu Jackson]

Macerator pumps do not "like" to run for extended times. RTFM. Don't know if this is your issue. My pump was 26 years old and finally bit, the dust, will replace it with a new one next week.

Good luck.