pump impeller question

I have a internal raw water intake pump for my Raritan Atlantes head that I'm overhauling. The pump appears to be the same as any typical small 12V impeller pump but I can not get the impeller out of this one. The thing that has me flustered is that the impeller shaft that protrudes slightly out of the impeller is a round shaft so what keeps the shaft from spinning inside the impeller? There is no flat on the shaft, keyway, nothing, and the damn impeller simply will not pull out so its either frozen to the shaft or there is something holding it. It is an absurd idea but has anyone ever seen an impeller that press fits on a shaft and if so how would you pull them as there is no way to get a puller into this small housing.

I even removed the back off the motor and tried tapping on the shaft to drive the armature backwards out of the motor and off the impeller but I did not want to get too aggressive until I was certain whether it is stuck or there is something holding it on. Raritan has a crappy exploded view but it is no help.

Any thoughts aside from get a bigger hammer.

The parts book shows a setscrew with what they call a " nylon patch" over it. This could be why you are not seeing it. It says it is 1/4-20 size. There are 2 pumps in this head, sounds like double trouble.

http://www.raritaneng.com/pdf_files/Atlantes Freedom/atfreeexpview.pdf

Hi Brooksie, many thanks for that!! Unfortunately that pump is the macerator. The pump I'm working on is the other one, the raw water intake. Also unfortunate is the fact the raw water pump they depict is not the same as mine.

Mine is this one, item 5 on exploded drawing, last page. It appears to have a flat on the shaft for the impeller but it doesn't.

I never thought about a hidden set screw though and I checked, it doesn't.

Sorry, missed which pump you were talking about.

What do the F005 setscrews shown on the new water pump pump do?

Well, that was really dumb. The exploded drawing I referred to is this link, item 5 on last page is my raw water pump.

http://www.raritaneng.com/pdf_files/atlantes/L242v1001.pdf

I think I'll open the lid to this crappy toilet, throw the pump in it and flush, then rip the whole thing off the floor and throw it overboard into the Marriana Trench......... my luck it will hit a Russian Nuclear sub on the way down who will interpret it as an attack and launch their nuclear warheads. When the world is lost to a nuclear holocaust it will be on Raritans conscience.

There are two #5 in the drawing you link to. Both are motors. I'm guessing you're having trouble with the rubber impeller in the intake pump. It's a strange pump but you should just be able to pull the impeller out. There is a flat on the motor shaft, a flat on the inside of the impeller and a flat on the stub shaft sticking out of the impeller. The motor shaft doesn't go all the way through. What you see with the rounded end is a stub shaft put in from the side of the impeller opposite of the motor. I've never seen another rubber impeller pump with a stub shaft like that.

The newer Atlantes toilets use a diaphragm pump that is quieter than the rubber impeller pump. You might want to upgrade to the new intake pump. Check with Raritan to see if you can.

Many thanks for the info Hopcar, I would "never" have guessed that strange setup you describe. I have rebuilt a lot of pumps but that's a first. It is obvious then that my impeller is simply frozen to the motor shaft. I'll try to pull that stub out then fill the hole with WD40 to see if I can't free up the impeller.

I did note that the new Atlantes head uses a diaphram pump but it appears to be an even worse cheap Jabsco pump with lots of little parts that require regular replacement. Couple this with the fact you have to remove the entire head to get at and it becomes a real pain.

Raritan sells the Atlantes without a raw water pump, allowing you to use whatever pump you like "externally". As an option, you can also buy the head with a factory installed internal pump, which is what I have. I think what I'll do if I can't fix this internal pump is junk it and mount a quality external pump out of sight.

Cheers, thanks again.

Which ever pump you decide to use, I like the idea of remote mounting it. That gets the noise out of the head. It also makes it easier to service or replace the pump and all pumps need to be serviced or replaced eventually.

To get frozen meal parts apart, use PB Blaster or Kroil. WD-40 won't do much compared to those.