T&T: Running or Sitting?

[Steve Sipe]

Ownyacht at aol.com wrote:
> The build up of crud in the heat exchangers and so forth...
>  
> Do you get more if you are running or sitting? Where does it come  from?
>  
> There are a few companies out there now that will flush your heat  exchangers 
> or you remove them and have them dipped.
>  
> R. Lee
>
>   
Running.

The heat exchanger has cold sea water on one side, hot engine antifreeze 
solution on the other. The engine coolant is generally around 180 
degrees. That's plenty hot to cause the minerals in the sea water to 
precipitate out of solution and collect on the surfaces of the 
exchanger. The same thing happens in a lot of other heat exchangers like 
a domestic water heater, boilers, etc. All are affected by 
precipitation, the effect which varies as the temperature and dissolved 
solids increase. Since sea water has such a high mineral content, or 
total dissolved solids, higher amounts of solids will come out of 
solution as the temperature increases. As the solids build up on the 
exchanger surfaces, the coating inhibits the transfer of heat, 
eventually to the point that the exchanger can no longer keep ahead of 
the load, and an overheating condition results.

The flushing uses acid or some other solution to dissolve those 
deposits. They go back into solution & the surfaces are freed of the 
insulating build up, restoring the exchanger to its full capacity.

Steve Sipe
Solo 4303 "Maerin"