Blackwater hose cleaning

I'm planning to use Sew Clean or Raritan CH (I'm told they're the same) to try to clean out my black water hoses.
My plan was to turn off the raw water supply to my Raritan Crown Head and add the diluted Sew Clean to the bowl and flush the cleaner into the lines and let it sit the recommended 6-12 hrs.
Then occurred to me that by turning off the supply, the macerator impeller won't run dry because of the added solution but the supply impeller will because the raw water is turned off.
Am I correct that this could burn up the supply impeller?
Should I make a guess as to how much raw water in brought in with the flush and leave that guesstimated amount out of the 1:5 dilution of the cleaner concentrate?
Anyone have experience with using these products with a similar raw water head?

Peggie Hall will be along soon to give you the straight dope. She actually invented Raritan CH.

I think Peggie usually recommends dilute muriatic acid to clean hoses.

The intake pump on the Crown is a small rubber impeller pump. Yes running it dry for more than a few seconds could damage it. It shouldn’t be hard to remove the impeller before you start.

Can't speak to your impeller question, but I can say I did have good luck when we had to use Sew Clean once. I removed the discharge hose from our toilet first, filled the hose manually, gradually... but that was also because we had a serious hard clog in that hose already...

-Chris

Then occurred to me that by turning off the supply, the macerator impeller won't run dry because of the added solution but the supply impeller will because the raw water is turned off.

The same motor runs both the intake and discharge impeller simultaneously, so the intake impeller will run dry if you cut off the water to the toilet.

I suggest you remove the intake line from its thru-hull (close the seacock first!) and stick it in it a bucket of Sew Clean diluted (or not, whatever the directions call for) and flush it through the system.

--Peggie

Thanks for the above tips.

Can anyone tell me if the Raritan Crown Head looses prime if the supply hose empties when I detach it from the thru-hull?

ORIF said:

Thanks for the above tips.

Can anyone tell me if the Raritan Crown Head looses prime if the supply hose empties when I detach it from the thru-hull?

Click to expand...

The intake pump on a crown head is self priming. If the impeller is in good shape and all connections are tight it should pick the water right up. I would guess it will self prime even four or five feet above the waterline.

All set then. Thanks

Also have Crown heads and didn't know about Sew Clean a couple years ago. I used a plumbers snake and dock water to open things up. Truly a crappy undertaking. Did I mention I'm converting to freshwater Raritan Sea Era heads? Peggie is helping with the planning.