Will be installing a used TT27 5T unit soon. In doing a little reading, it seems there may some some concerns with the heat exchangers prematurely failing in these. I would like to confirm or debunk this. I am not sure if the water exchanger was designed to be replaced easily or if that is a complete system breakdown. I know the unit was previously installed in 05 and was used as an open loop water source pump which REALLY concerns me because this one does not have the cupro-nickel exchanger. It might have had a lot of life sucked out.

I know I have read about potential problems in the air exchangers and there is apparently a different exchanger for them now. This might just be Inet fluff but have to ask.

When it is recommissioned, I would only use a closed loop system for maint purposed and would prefer propylene glycol based. I know many are using Methanol but my experienced with Methanol are from racing and it is NOT nice to really any metal so that and Copper don't excite me. Any experiences on closed loop fluids?

This one does have the HWG but I do not think it was in use. I planned to acid flush the exchangers before putting back in service but there may already be substantial damage. I know the water that was running in it was very high in Manganese. Could be worse I guess but that probably means there is scale in it.