Water Heater.

seahawkseahawk Kingston,Ontario, CAMember Posts: 62
Im hoping that someone on the group can confirm something for me.......pretty sure that know the answer but I'f I'm wrong , its gonna be an expensive mistake.    So.....I have an Atwood water heater that is dual electric and engine heated. I suspect the heater is leaking so I've drained it and I'm going to bypass it til I can confirm whether or not thats where my leak in the engine room is coming from. Is it OK to run the engine without water in the heater. Is there any chance that the heater could overheat if its empty. I'm assuming that the way the heater works is via a "heat exchanger" so I think I should be OK......Thanks for any help with this.  


  • GrahamuGrahamu Lefroy, Lake Simcoe, ON, CDAMember Posts: 620 ✭✭✭
    You will be OK just make sure that no one turns on the hot water breaker on the panel.
  • seahawkseahawk Kingston,Ontario, CAMember Posts: 62
    Thats what I was hoping you would say. Thanks so much for the confirmation.....much appreciated.

  • Liberty44140Liberty44140 Bay Village & Marblehead, OH.Member Posts: 3,945 ✭✭✭✭✭
    yep exactly, heating element is only on when the breaker is on, not when the unit is acting as a heat exchanger, will be fine. 
    07' Cruisers 390 (Previous Rinker's: 06' 342EC & 01' 310FV)

  • seahawkseahawk Kingston,Ontario, CAMember Posts: 62
    I guess what I'd also like to confirm is that, could I possibly cause an 'overheating hazard' inside the water heater by running hot engine water through the heater tank if it has no water in it...???
  • GrahamuGrahamu Lefroy, Lake Simcoe, ON, CDAMember Posts: 620 ✭✭✭
    edited June 13
    If your engine thermostat is working correctly the water temperature will not be above 165F. If you have disconnected the fresh water and by-passed it leave the connections on the heater open to vent it. If you are still concerned disconnect the engine supply and connect them together by-passing the heater element. I wouldn't recommend that if your engine supply is closed cooled as you will loose coolant.
  • seahawkseahawk Kingston,Ontario, CAMember Posts: 62
    I really appreciate having all the expertise of the members of this group at our fingertips. Thanx everyone for the info. Very much appreciated.    
  • raybo3raybo3 East Boston MAAdministrator Posts: 5,304 admin
    Is there a way to adjust the temp on the heating elements (I haven't looked that closely at it yet)? My high temp safety keeps popping so I assume that its "running away" while turned on.
    2002 342 Fiesta Vee PC Point Of Pines YC Revere MA. popyc.org     [email protected]
  • GrahamuGrahamu Lefroy, Lake Simcoe, ON, CDAMember Posts: 620 ✭✭✭
    Some hot water heaters are adjustable, some have a thermostat for the electric heater element. You might have to  replace it.
  • seahawkseahawk Kingston,Ontario, CAMember Posts: 62
    Another question related to the water system on a 280 EC ......I’ve drained all the water from the water tank and the water heater. There should be no more water in the heater. I’ve refilled the water tank. If I turn on the water pump, to pressurize the system, and only open the cold water faucets, will water from the tank go through the water heater..???....I want to leave the water heater empty but would still like to have cold water to use at the sinks and in the Vacuuflush toilet. Can this be done without disconnecting the water heater and bypassing it...????? 
  • YYZRCYYZRC Georgian BayMember Posts: 3,501 ✭✭✭✭✭
    Some water will enter the water heater. If you open one of the hot taps it will drain the air and replace with water. 

    Best approach is to disconnect the cold supply line from the water heater and cap it. 
    2008 350 EC on Georgian Bay
  • seahawkseahawk Kingston,Ontario, CAMember Posts: 62
    The previous owner had the heater bypassed when we bought the boat. We thought it was because the system had just been winterized. Maybe not. He had used a Sharkbite to join the hot and cold water lines from the heater. When I went to reinstall that today it leaked badly as soon as I pressurized the system. Either the Sharkbite fitting is no good or more likely the pex line is not smooth where it enters the Sharkbite. So I took off the Sharkbite and reinstalled the lines through the heater until I can get to a hardware store to either replace the pex or get a new connector of some sort. In the meantime I was hoping to be able to use ONLY the Vacuuflush and the cold water taps hoping that if I stay away from the hot taps , water won’t be routed through the heater..
  • YYZRCYYZRC Georgian BayMember Posts: 3,501 ✭✭✭✭✭
    edited June 20
    On my boat there is a tee connector from the cold supply down to the water heater. If yours is the same you could just replace the tee with a straight connector. 

    Tee in top left of pic. 

    2008 350 EC on Georgian Bay
  • seahawkseahawk Kingston,Ontario, CAMember Posts: 62
    edited June 21
    I think the idea of doing that or capping the cold “in” is the best solution. It’s only going to be a temporary fix til I solve the larger issue....is the heater leaking.  Thanks for the input. I’ll head over to Home Depot tomorrow and find some kind of cap for the pex line.  Much appreciated. 
    Post edited by seahawk on
  • Cableguy GregCableguy Greg Pittsburgh, PAMember Posts: 4,820 ✭✭✭✭✭
    My bypass on my 280 is made with the Flair-it fittings. It is a T valve on each side and it works well. If you cap it, you will still have cold water. 
    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA "Blue Ayes"
    Go Steelers!!!
  • seahawkseahawk Kingston,Ontario, CAMember Posts: 62
    Thanx Greg.......I'll check out Flair-it......

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