Iwaki pump rebuilding - Any lessons learned?

H

HSLee

[I'm running two MD70RLT pumps for the returns from my sump to tank. After 3 years of running, flow has greatly reduced since new, I suspect due to detritus and Calcium buildup within the pump. I plan to disassemble them for cleaning in attempt to regain spec output flow.

Any BTDT lessons learned out there? I believe the assembly is simple to take apart, clean and reassemble without need for replacing parts (if none broken).

Also considering replacing these 2 power and temp hogs with a single high-capacity and more efficient pump. Any recommendations? I am considering the big Sequence Hammerhead pump sold by PremiumAquatics and CustomAquatics.

The MD70RLT outputs 1500 gph at 4' with 32' max head.
Equal or better flow performance is desired.

Thanks.]
 
[I think the impeller assembly is like the iwaki 100's and if so, you will want to check closely in the internal impeller channels (where to water is 'slung' to the outside edge of the impeller and out to the pump outlet) to check for obstructions. I recently repainted/cleaned s pump and found 2 small snail shells jammed in the water channel and wouldn't have known they were there without using a small tube cleaner - bristle brush - to push through the impeller channels to the outside edge. Also, there is a large 'O' ring of rubber that is between the body and impeller cover that you will want to remove/clean a bit,...just be careful extracting it as they are a bit pricey (for a rubber O ring that is). I added a little silicon grease to the O ring when replaced, but other than that, it was pretty straight forward. HTH]
 
[I service my pumps about once every year and a half to two years. I'm still amazed by the buildup on the impeller assembly and every time I do it I vow to perform this service more often. Just take your time and be careful with the parts, I'm not sure about the Iwaki but my pump has a ceramic shaft which is pretty brittle if your were to drop it. Bottle brush, an old toothbrush, vinegar and Q-tips are your friends for this procedure. Don't forget to re-lube the O-rings and be careful when you re-assemble to make sure they don't get pinched.]
 
[Doug, Andy,
Thanks for the advice. I finished the cleanup and rebuild of the 2 pumps last night. Time consuming, but easy. Found some small rocks caught into the input strainer section of both pumps. Lots of scum and calcified stuff on the chamber walls. Used about a gallon of vinegar to clean it off. Both pumps are working again. Looks like an annual maintenance/rebuild would be good for these pumps. I think I'll have to start thinking about how to clean or replace the rest of the plumbing lines, soon.]
 
[I use a pair of iwaki's as my return pump. I usually switch them out every year. As I was cleaning the one I took out recently I did notice how the blades on the impellor were worn down so they were rounded off and no longer right angles. So this time I am replacing the impellor something I have not done before. I bet it will make a big difference in the water it pumps.]
 
[Rick,
Curious. Where did you buy your iwaki impellers, for which model(s) and price range? Want to know for future reference.
I suspect that they're not cheap, being encapsulated in plastic, and balanced.]
 
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