Black water pump clogged

[Jofang]

Our black water pump that draws from the cassette has become clogged on the suction side. We don't put paper into the toilet, so the blockage can only be poo. I have dismantled the suction pipe from the cassette to the pump as far as I can but the last 12" of the suction pipe is buried inside the floor. I have primed this section of suction pipe with water to give about a foot of positive head to the pump but the pump cannot pull sufficiently to draw the water through the blockage. My next line of attack is with some form of drain chemical but I'm not sure which one is safe to use with motorhome pipework and pump. Can anyone please advise?

 

[Jev88]

Sounds like a small flexible rod would do the job?

 

[Jofang]

Thanks Jev. I really thought the priming would work, but alas no. As a last resort I can disconnect the pipework at the pump inlet, but there's now a pint of nasty water still in the pipe above the pump and no way of catching it with a bucket, bowl or whatever. Whoever designed this system with no way to service or access it must have had their head up their arse.

 

[Mohawk Mo]

Sounds like a big job to me ....

 

[Jev88]

Domestic toilet blockages you clear with a plunger work best if you can give a good 'suck' rather than trying to blow the blockage out. But I guess that would be hard to achieve in a cassette?

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[Jofang]

I'm going to strip the whole lot down. I've ordered an overhaul kit for the Jabsco poo pump, as I fear this is where the problem may be, as the pump is almost 10 years old. This is going to be a sh1t job, but can't keep mucking about, as this system with a 60 litre black tank allows us to wild camp for 2 weeks without having to empty the cassette.

 

[PP Bear]

Sounds like a big job to me ....

Sounds like a bigger jobbie to me