Last weekend i went to the boat and turned on hot water heater. About 1/2 hour later the water pump started cycling. Removed cushois and found that the pressure relief valve was partially open and hot water was running into bilge. tapped on the end of valve to see if it was stuck open, but no result. Turned off heater and drained some of the hot water from tank and it stopped leaking. Also all fresh water tanks were full. My question is, is it a thermastat problem (according to the manual these are preset and there is no adjustment bad idea in my opinion) or is it a bad pressure relief valve?
Thanks, Mark
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Mark Middleton
S/V Lunacy
SW Michigan
2002 C36 MK II TR WK M35B
Mark, I believe the valve you refer to is a pressure release valve and is not temperature sensitive, except to say that a defective thermostat will cause the pressure to rise and the valve to open. My point is to ask that you try shutting off your water heater at the service panel and see if the water heater pressure valve operates normally under normal pressure but with out the heater element energized. That test should tell you the condition of the valve. If it's the thermostat, you will probably get some steam from the pressure valve.
Take the temperature of your water heater hot water, perhaps others on this board can compare notes with your results.
Unfortunately my boat is in winter storage for the next 7 months so I can't offer a temperature compairson.
Bill Matley
Catalina 36 #1252
Bill Matley
Duncan Bay Boat Club
Cheboygan, Michigan
Lakes Huron, Michigan,
Canadian North Channel
"Spirit of Aloha" Hull #1252
Mark, you noted you had it on for 1/2 an hour. You only need to leave the electricity on for 15 to 20 minutes to get the water hot. If for any reason pressure builds up in the tank, the PRV will pop, it's designed to do just that. You may be better off replacing the PRV at a hardware store because once popped sometime debris gets in the valve and they never really shut again.
Another handy hint: get in the habit of using the hot water faucet all the time, even and especially when the water is cold. This "moves" water through the hot water heater and avoids potential bad smells from sitting water if you never use the hot water faucet or only rarely. It's a habit we learned about and got into and it works.
Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)
Thanks, sounds like you guys put me on the right track
Mark Middleton
S/V Lunacy
SW Michigan
2002 C36 MK II TR WK M35B
What I thought was simple may not be! My hot water tank ( off at the panel) dumps my fresh water when the engine gets to temp. Am not losing coolant and guard reads about 175 when running. Can I shut off the water to the tank then only lose 6 gallons and run with an empty hot water tank? I could then add water back to tank when we arrive at dock by opening the valves. Not sure if the coils in the hot water tank have to be submerged.... thanks all!
Did you check the pressure and temperature relief valve on the hot water tank? They can crap out over time (and you may be able to replace with one from a plumbing supply house -- I think its no different from the relief valves used in home hot water tanks.
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
I just replaced my water heater due to coolant leak. They have finite number of years of life.
Sail La Vie 1999 Catalina 36 MKII, M35B-17031, Coyote Point, San Mateo, CA
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