Universal M2-12: Hot Water Heater By-pass Question

[phallock]

About a year ago I took my hot water heater circuit offline due to some engine work and bad scaling/clogging in the circuit (still a pretty new boat to me at the time).

I'm putting it back together now. I had a 6" hose installed to loop the circuit; that's off now and the hoses to the hot water heater, located in the lazarette, have been reattached.

Problem: I'm not sure which nipple/connection is the outflow from the fresh water pump, and which is the inflow. The manual is no help whatsoever, nothing is marked.

Apologies for the fuzzy picture, it was dark and taken with a camera phone. I assumed that the connection at the foreground hose was the output from the pump, and should be connected to the inlet at the water heater. The other hose attaches to a nipple just underneath the thermostat housing, which I assumed was the return from the hot water heater to the engine. When I ran it like this, all the coolant from the engine and manifold was pumped into the overflow tank in the lazarette, and stayed there.

Couldn't work on it much more today, so I thought I'd see if anyone can verify which is the inlet and which is the outlet.

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[Lancerbye]

Normally in a heater application inlet is lower than outlet and the trapped air has to be bled out of your system through the top of the tank if you have a bleed screw or through the expansion chamber.