Hot Water Holding Tank Heater Problems

[ITMaster]

I have a C-387 that has an electric and heat exchanger method for heating up the water in the hot water tank. Guess we all have the same. The water heats up really great with the electric unit, however when on the hook, the water heater basically does not work unless the engine is operated with the boat under way (obviously not now on the hook under way). To sit on the hook and charge the batteries up for say 30 to 45 minutes at 180 F engine temp displayed on the gauge does absolutely zippo! I have pulled the lines coming off the header pipes at the supply and return ports on top the Yanmar between the engine and the heat exchanger and blown them out each direction with compressed air to comfirm that circulation exists without any restrictions. Any ideas out there?

 

[doug]

Water Heater

Check for air in the lines. There is a valve somewhere in the hose to bleed offair. This helps.

 

[Calif. Ted]

Doug is refering to the hot water (coolant)

line from the engine, it has tendency to form an air lock as water heater is usually highest point in the system. Bleed valve is usually located in locker near heater. Your problem is a little confusing in that you state the heater works when the boat is underway but not on the hook. I don't believe my engine will get as warm as 180 when not "under load" (pushing the boat), it doesn't seem it should get that warm in 20 or 30 minutes in neutral.

 

[ITMaster]

Thanks for the idea

I appreciate the idea, I did locate the air bleeder valve. Oddly enough, it is on the lower side of the hot water tank; I would think that the air would collect up top and that Catalina would put the bleeder valve up there. I'll give that a try however and I bet it takes care of the problem. And you're right Ted, the water temp itself with 50 F raw water supply here in the Chesapeake this time of year will only let the coolant temp get up to about 140-145. The temp I see on the gauge at the instrument panel seems to be the block temp based on my explorations with the hand held LED temp meter, not that of the coolant coming from the hoses going to the heat exchanger. Thanks much for the help, I have trouble looking outside the box sometimes.