Head motor

[Goldfinger]

Over the past 6 weeks each weekend we visit the boat, the head's motor (TMC 12v with macerator... motor is 2 years old) has become increasingly stubborn to run. It clicks, pauses but then runs normally, and any subsequent use is fine until the following week.

Well it did but now it's worse. I have to turn the motor manually (with a screw driver) at the same time as turning it on. When it starts it runs fine and will run fine the next day without assistance... but a week later it has reverted to needing help with the screwdriver.

Any ideas about what's happening?

Thanks in advance.
GF

[JPA Cate]

First, verify all the electrical connections are clean & good. Actually, I suspect you've got deposits from salt water interaction with urine building up in there, but let's hope not. If you have a reason to suspect the macerator's dying, it may be more pleasant to fit a new one than try and clean up the old one.

You can try flushing 1/2 c. or so of salad oil through it, in the unlikely event that the problem is just a lack of lubrication, but really, the oil business is more of a maintenance deal than a repair one.

Ann

[peghall]

Pouring oil down the toilet only lubricates MANUAL toilet pumps...Electric toilets have sealed motors, so pouring oil down the toilet can't lubricate it...and a macerator is just a chopper blade in the discharge pump (see parts 19 & 20 on page 6 in the manual)...oil won't do a thing for it either.

Your problem is a stuck impeller (see parts 18 and 29 on page 6 in the drawing in the owners manual here) TMC Electric toilet owners manual ...most likely it's the discharge impeller (29) . Waste and sea water are sticky, so when the toilet sits, impellers can get stuck to the inside of its housing. Once you've freed it, the toilet runs normally...till the toilet sits again. (Same thing happens to Jabsco macerator pumps, btw...and turning with a screwdriver is the fix for it too). Running plenty of clean FRESH water through it to clean out any remaining waste before the boat will sit may help to prevent it....which you definitely want to do 'cuz stress on stuck impeller vanes will weaken the vanes and cause one to break. A new impeller--which requires taking the pump assembly apart--is the only cure for that.

Fwiw, TCM toilets aren't the most durable, so if the problem is getting worse the motor may also be getting weaker...no longer has the "ooomph" needed to break the impeller free. Another reason you want to prevent it from getting stuck in the first place.

[Goldfinger]

Originally Posted by Ann T. Cate

First, verify all the electrical connections are clean & good. Actually, I suspect you've got deposits from salt water interaction with urine building up in there, but let's hope not. If you have a reason to suspect the macerator's dying, it may be more pleasant to fit a new one than try and clean up the old one.

You can try flushing 1/2 c. or so of salad oil through it, in the unlikely event that the problem is just a lack of lubrication, but really, the oil business is more of a maintenance deal than a repair one.

Ann

OK thanks Ann,

Checked all the connections and nothing OBVIOUS there. See also my answer to Peg below.

[Goldfinger]

Originally Posted by peghall

Your problem is a stuck impeller (see parts 18 and 29 on page 6 in the drawing in the owners manual here) TMC Electric toilet owners manual ...most likely it's the discharge impeller (29) . Waste and sea water are sticky, so when the toilet sits, impellers can get stuck to the inside of its housing. Once you've freed it, the toilet runs normally...till the toilet sits again. (Same thing happens to Jabsco macerator pumps, btw...and turning with a screwdriver is the fix for it too). Running plenty of clean FRESH water through it to clean out any remaining waste before the boat will sit may help to prevent it....which you definitely want to do 'cuz stress on stuck impeller vanes will weaken the vanes and cause one to break. A new impeller--which requires taking the pump assembly apart--is the only cure for that.

Thanks Peg, Sounds like the stuck impeller is worth investigating further. It does surprise me though, as it should be pretty clean in there. I do fresh (often hot) water flush the toilet every time we leave the boat. (I have plumbed the head intake to take water from the hand basin if I choose) and very regularly flush vinegar through the system too. I will try a further STRENUOUS clean and if that's not the solution I'll replace the impeller. Fingers crossed.

Also thanks for the link

Also Also, tried to hit the "thanks" button with no luck... so thanks again!

[Lepke]

I don't have a marine heads anymore, but have repaired many ac and dc motors. I never had a stuck impeller, but the problem you have is consistent with bad contacts, a bad solenoid or the switch that controls the solenoid. Some motors have brushes that wear fast and the spring no longer holds them tight against the armature. Also when sealed motors use up the lube included in the bearings, they can act like yours. If you end up taking out the motor and can open it up, you could re-oil or re-grease the bearings.

[Goldfinger]

Originally Posted by Lepke

... but the problem you have is consistent with bad contacts, a bad solenoid or the switch that controls the solenoid. Some motors have brushes that wear fast and the spring no longer holds them tight against the armature. Also when sealed motors use up the lube included in the bearings, they can act like yours. If you end up taking out the motor and can open it up, you could re-oil or re-grease the bearings.

Ok thanks. Not sure if I can get into the motor to re-lube but will look at it. No doubt which ever is the most expensive and time-consuming solution that will be my problem.

[Goldfinger]

UPDATE:

pulled the impeller housing apart. Very clean inside as expected. The impeller seemed to be fine. There was a small nick on the flat surface of the wearplate. But nothing OBVIOUSLY awry. So replaced impeller and wearplate, anyway since I had them apart and had spares.

So far the head seems to be working fine with no sticking (the original problem) but the test will be when I leave the head for a week or so and then try it.

[peghall]

So far the head seems to be working fine with no sticking (the original problem) but the test will be when I leave the head for a week or so and then try it.

Unless you flush some clean fresh water through it to rinse all the waste and sea water out of it before leaving the boat each time, it may be fine for a while, but I guarantee you that sooner or later you'll have the same problem again: impeller stuck tight to its housing.

[Goldfinger]

Originally Posted by peghall

Unless you flush some clean fresh water through it to rinse all the waste and sea water out of it before leaving the boat each time, it may be fine for a while, but I guarantee you that sooner or later you'll have the same problem again: impeller stuck tight to its housing.

I do. Often to the point of OCD, together with regular doses of vinegar, that's why I was puzzled. I'll update in a couple of weeks to see if this recurrs. If so0 it might be the motor as suggested by Lepke.

thanks