Originally Posted by Joew2604
I just installed a new Raritan water heater , Yamaha 3HM35F engine. The electric works just fine, hot and cold water runs great. FW hoses are connected up. Couple of days later started engine and the alarm came on. Think did I connect the FW in and out correctly. Does it make any difference which way the FW flows through the heater? Could it be an airlock? If so what should I do. Appreciate any suggestions. Many thanks
Probably an air lock. No difference in "direction" of flow.
Find the highest point in the entire engine/water heater system as a whole and bleed out any air.
If you didn't add any coolant, you'll probably need that, too, to account for the new hoses and exchanger volume.