View Single Post
  #23   IP: 73.163.155.191
Old 03-26-2021, 07:46 PM
ernst ernst is offline
Senior Member
 
Join Date: Dec 2009
Location: Baltimore, MD
Posts: 148
Thanks: 59
Thanked 14 Times in 10 Posts
Quote:
Originally Posted by ndutton View Post
Actually, these pumps WILL self prime when they are in newer, less worn condition. Your measurements indicate cavity wear (completely normal and expected as the pump ages) which explains its inability to self prime anymore. Because of that, designing the raw water intake path to be entirely below the waterline would help matters in the current situation.

But so would a new MMI 502 raw water pump that doesn't have cavity wear and will prime itself readily. Your pump is telling you it's about time to retire.
Good to know! So it looks my installation was not as stupid as I feared.

I am a bit surprised though that the pump already has considerable wear. As I said, this pump is not that old, it came new with the freshwater cooling system from Indigo that I installed 10 years ago (maybe a bit more). I haven't checked the hour meter but I guess the pump has only a few hundred hours on the clock. I use the Globe Run-Dry impeller for this pump (but NOT for the coolant side), could that have to do with the wear?

I think I will re-design the winterizing system. Thanks for all your help!
Reply With Quote