I found that my Universal 5432 had the heat exchanger piped in series with the water heater, and it always overheated at higher RPM's.  After I removed the water heater from that circuit it no longer overheated.  I also changed the capacity of the sea water pump that provided some relief, but not enough.  To get faster water temperature rise I removed the thermostate with a hole and replaced it with one that had no holes.  pictures etc. on sankaty's website.

Hi Markus,

Got it. So after you removed it from series, is it now in parallel; i.e. you are still using heat from the exchanger for the water heater, but no longer in series? I understand that the thermostat without holes will surely give a quicker rise in temperture, but after you removed the hot water heater from the series, did the normal engine operating temperature stabilize at slightly higher, the same, or slightly lower than before?

Randy

Yes the water heater is now in parallel see diagram for type 1 connection by clicking here.

Once I switched to the parallel connection the engine no longer overheated above 6kn.

Markus Ritter:

Yes the water heater is now in parallel see diagram for type 1 connection by clicking here.

Once I switched to the parallel connection the engine no longer overheated above 6kn.

Hi Markus,

I clicked on the Diagram link and it is terrific. Can I post this under "Articles" - - the articles are under the News tab? I think this is something everyone would like to see. Of course I will give full attribution to you for the post.

Let me know and I will put it up in Articles.

By the way, I'm the co-founder of SailAngle.com and a long time member of the USPS. You can look up my profile by searching the members for Vance Randy White, but I go by Randy. You seem like a very smart and knowledgable boater so I am also sending you a Friend Request - - when you accept we will be joined on SailAngle.com.

Cheers,

Randy

Please feel free to post it. Markus Ritter

I have the parallel hose set up on my Universal M25. The hoses that feed the water heater are considerably smaller than the hoses to the heat exchanger. Could the cause of your previous overheating be flow restriction caused by too small a hose not allowing sufficient flow rather than a deficiency in a series set up?

You sure hit the nail on the head.
Now the whole heater with its restrictions is no longer
in the cooling circuit so it can not impede the flow
through the heat exchanger.