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Atwood water heater EHM6-SM manifold ?-gctid557237

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    Atwood water heater EHM6-SM manifold ?-gctid557237

    Hi all,

    Boat is a 1997 2855 with 7.4 Bravo 3. I have an Atwood water heater noted in subject line. It currently is not connected to the water supply from the engine (raw water cooled in fresh water). Is there a reason not to hook this up so I can have hot water while underway? I understand the supply line comes from the top of the recirc pump. This currently has a soft hose turning 90 degrees back into or just under the thermostat housing. Do I install a "T" fitting here? Which attach point on the water heater is the supply, which is return (for the manifold)? The return line will come back to the egine at the recirc pump on the starboard side, correct? Any other advice before I tackle this one?


    The output hose going to the exhaust(manifold) system from the raw water system should be the one that goes into the hot water heater. This is where the raw water is the hottest! And welcome
    Joon, Kathy, Jaden & Tristan
    Uniflite 42 AC, DD 671N
    93 3058 sold
    92 2855 (day boat)
    91 Fourwinns 205 (lake boat)
    Longbranch WA
    Life is Good


      Is this the hose from the thermostat to the bottom of the exhaust manifold? Attaches where the tee is for the drain? I assume I route that through the water heater manifold and then back to the bottom of the exhaust manifold?


        The plumbing for the Water Heater's "heat exchanger" will not involve the T-stat housing, nor the exhaust manifolds.

        You'll want the supply to be from upstream of the thermostat. Most commonly the port within the intake manifold... if so equipped.

        This will offer a mild Positive pressure due to the Circ Pump providing pressure that the thermostat is holding back.

        You want the return to be at the Starboard-most port in the Circulating pump due to the mild Negative pressure that is present here.

        This creates a balance so that flow may occur to/from the WH.

        Here are a few diagrams to look at.

        The plumbing will be the same for a Raw Water cooled engine.

        Rick E. Gresham, Oregon
        2850 Bounty Sedan Flybridge model
        Twin 280 HP 5.7's w/ Closed Cooling
        Volvo Penta DuoProp Drives
        Kohler 4 CZ Gen Set


          Thanks. I'll give it a try!