Yanmar coolant connections to Hot water heater

[gerber30]

Can someone post some pictures of where the hot water heater is plumbed into the coolant system for a Yanmar. My 1997 28 TE originally had a Penisular and was re-powered with a Yanmar and the lines to the water heater were never hooked up. As a result I only get hot water when plugged in. Thanks

[RobS]

The water heater inlet is at a fitting on the block just above the thermostat (next to the heat exchanger cap above the alternator). The outlet is on a fitting next to the water temp switch and sender on the cooling pipe that wraps around the timing cover. I can take and post pictures if needed..

[gerber30]

Thanks I am on the boat tonight, I will take a look in the morning.

[RobS]

I too am spending the night aboard so here are photos of water heater hose connections at engine as described above.

[gerber30]

Great pictures, I found the inlet it has a plug in it now. The outlet though on mine there are 3 sensors and in your picture I see 2 sensors and then the outlet hose. Any ideas? Does yours have tee on it with the sensor off to the side?

[RobS]

No tee. Not sure what that 3rd sensor could be but based on its location it must be monitoring engine coolant temp, just not sure what it is connected to...

[gerber30]

Thanks Rob, I will check with my Yanmar guy and see what he can come up with. I will also post a picture of what I was describing next time I am at the boat. Thanks

[avius]

Thanks Rob, I will check with my Yanmar guy and see what he can come up with. I will also post a picture of what I was describing next time I am at the boat. Thanks

I am trying to install a heater and mine also has three plugs, I believe they are (from L-R) Temp Sender Switch (has a red dot), Another sender (w/green dot), Thermistor. did you ever find out how to pipe it?
AV

[gerber30]

The return is located mid engine top just behind the top of the timing belt cover. My motor is a 2005 yanmar engine box on a 1997 28te. I still have not plumbed it. Do not need it much in Florida. Good luck.

[gerber30]

Photo of the plug location for the return line.

[avius]

Ok. awesome thanks. not much need for hot water here in hawaii either , except after a night dive!
I have just started researching a heater, but I don't under stand how the coolant water heats the freshwater shower... is there like a heat exchanger or copper coils in the holding tank?

Also did you ever find out what the green sensor is? I had to trace the first one on the left ( red dot) because its been sending over heating signals just after 5 minutes of operation. But the green one I am not sure.
Goodtimes
AV

[gerber30]

The warm Engine coolant travels throught the water heater via the connections we have talked about and heats the water. Essentially a heat exchanger. Check Defender.com for a water heater, they have a great selection and good prices. Not sure what the green sensor is, my mechanic named all three but i can't remember what he said the green sensor was for!! Sorry.

[RobS]

Check the wiring diagram in the Yanmar manual and see what that color wire is for. The White w/Black tracer is the cw temp sender, the White w/Blue tracer is the cw temp switch.

[Serenity]

What does a cw temp switch do?

[RobS]

What does a cw temp switch do?

It triggers the high temp alarm and light. On the left is the switch, on the right is the VDO sender I installed this winter as part of my new dash with new gauges.