ESPAR D5WSC Hydronic flushing/coolant question

1 post / 0 new
Absolutely's picture
Absolutely
Offline
Joined: 4/21/21
Posts: 24
ESPAR D5WSC Hydronic flushing/coolant question

Hi all,

We have an  ESPAR D5WSC Hydronic system on-board which runs 3 heat exchanger stations and can heat the hot water tank.  The coolant in the heater system is Prestone (green) while the boat's motor is using Delo ELC (red or pink). 

I have not been using the hot water branch of the Espar because I am concerned about the two coolants cross-mixing in the few feet of hosing to and from the water heater, not to mention the water jacket inside the heater itself.

First off, is this a real concern?  It is my understanding that one should not mix colors of coolant as they can sludge.

Second, if it is a concern, I am thinking of flushing the Espar system clean and switching to Delo ELC so the coolant types match.  I don't think I can fully drain the system due to all of the dips and turns of the hoses throughout the boat.  So, I am thinking of draining the pressure tank and overflow tank and any hose connections I can reach that are low in position.  Then fill the system with straight water and run for 15 minutes.  Drain out the water as before and re-fill with water and run for another 15 minutes.  Then fill the system with the new coolant and be done.

Also, I understand that the heater systems will carry more heat if you use less coolant/more water, and one doesn't really need to run 50/50 coolant if they aren't in super cold environments.  However, I am again concerned with the coolants of the engine and Espar system mixing at the water heater and effecting one another.  Therefore, should I just run the 50/50 mix in the Espar?
 

Dale and Nikki

1998 C36 mkII SR hailing from Poulsbo, WA
1989 C25 TR/WK