Connecting hotwater system to Yanmar heat exchange

[Akarua01]

Can anybody send me a photo of where to connect the two hoses to the engine on a Yanmar 3jh3e for the hot water to flow through the hot water tank I have it hooked up but after running the engine for 35minuts no hot water (it's a 20liter tank).

 

[Hagar]

There are 2 tapped ports, one on the top of the water pump and another about 3 inches away on the thermostat housing that are the connections. The brass ones shown here. It doesn't matter which you use for in and out. Be aware that if you are idling the engine it can take a long time to heat the water. I would guess it may take well over an hour. Also, make sure there are no air traps in your lines. On my boat (4j engine but the same design) I have to bring the engine up to temperature and rev it above 2500 to push the air out the system.

 

[Jim CT35]

Hagar is right about having a bubble in the heater circuit. I have a 3JH and the top of the heater is above the engine. To get rid of the bubble I routed one of the hoses above the heater and put a "tee" in it. This allows me to bleed the system. I can gently add coolant with a funnel, run it for a while, then top it off. Sometimes it takes several times to get rid of the bubble.

For making hot water I usually run it at about 1600 RPM for about a half hour. This also gets the alternator pumping electricity into the battery.

 

[Hagar]

A bit more...
You can check for trapped air by feeling the temperature of the circulation hoses near the water heater. Once the engine is warm the hoses should also be warm. If not then the trapped air keeps the coolant from circulating.