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1994 390CPMY water heater replacement

Posted: August 18th, 2022, 6:28 pm
by tonyiiiafl
Been getting water in the forward and center bilge, and looks everywhere except the right place. Had a decent amount in the bilge wheel we were gone 1.5 hours. Touched the water and it was HOT. Saw a wet pot in front of the heater, so the original heater has given up the ghost. Anyone every replace one? Has a rear heat exchanger connection, and am looking for same. Doesn’t look too bad. OF course, we were planning a weekend away and a week for labor day. Hope to be able to replace next saturday, but we shall see. Looks a bit tight.
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Re: 1994 390CPMY water heater replacement

Posted: August 18th, 2022, 7:10 pm
by tonyiiiafl
UPDATE: I was poking about, and heard water sort of running. I am deducing that it is the safety valve failing. I do not see how the water in the fwd bilge could be so hot from a drip, so it had to be a flow. As for the puddle, wet spot. The fitting was wet underneath. I may have dodged the bullet. Replacing the safety valve tomorrow. STAY TINED for more of Tony's adventures! Truthfully, I was going to replace the A/C unit next year as it works OK, but getting very noisy. I would hate to have to pull the water heater out again to get the A/C out.

Re: 1994 390CPMY water heater replacement

Posted: August 18th, 2022, 9:51 pm
by Viper
Tony, if the valve is leaking, that's one thing as that's not unusual after several years, especially if it doesn't get exercised periodically. If on the other hand it was an intentional discharge, then it was doing its job and you may have a defective t-stat and high limit switch that aren't shutting off when they should.

Re: 1994 390CPMY water heater replacement

Posted: August 19th, 2022, 2:35 am
by tonyiiiafl
Yes, I thought of that as the water is hot as Hades.I am going to see what goes, as I did some snapping of the valve and now no issues or water. For now, I shut the shore water off at night, we usually ALWAYS shut off when we are away even for a few hours, as with the heater, it gets shut off at night also. If this demon will wait til the end of th season, I am going to tackle it in April next year, along with teh A/C. NOW that will be another thread as I have more wires and TWO boxes for it. Going to need some guidance on the A/C!

Re: 1994 390CPMY water heater replacement

Posted: August 19th, 2022, 9:05 am
by bud37
For what its worth here for you....we always managed water heaters on our boats......only put on when needed....we never left them on for extended periods.

Re: 1994 390CPMY water heater replacement

Posted: August 19th, 2022, 10:23 am
by tonyiiiafl
Same here. On forbids and then off when not needed

Re: 1994 390CPMY water heater replacement

Posted: August 19th, 2022, 10:42 am
by Midnightsun
Mine is on all the time and always has been on all my boats. Dishes and showers are much better with hot water. :captain2:

Re: 1994 390CPMY water heater replacement

Posted: August 19th, 2022, 2:28 pm
by tonyiiiafl
I do get hot water in 45 minutes

Re: 1994 390CPMY water heater replacement

Posted: August 19th, 2022, 4:51 pm
by tonyiiiafl
SO, I got into it, and when water is leaking the safety valve is hOT, The water always came out HOT. Plumbing supply store said to just use a 175LB valve. What a dope! I got one coming Sunday with teh same specs of 150LBS at 210. Also, checked DEFENDER and got a thermostat and aa high limit switch. So with all 3 I hope to be good to go. Then I will not have=ve steam for hot water, one hopes, but the factory 140 degrees

Re: 1994 390CPMY water heater replacement

Posted: August 20th, 2022, 9:23 am
by km1125
I always thought it was interesting/weird that you get hotter water from the heat exchangers than from the electric elements. Makes sense though, as the engines are regulated at 160-180F, much higher than the usual water heater thermostat.