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Hot Water heater tank, but only cold coming from faucet

Oct 25, 2019
2
Hunter 36 Pittsburgh
Just sized up to a 41 Hunter from a 36. Hot Water heater tank gets hot as I can feel the fittings and element draws power, but when I turn on the hot faucets, only cold comes out. I followed the lines and read the water schematics with no luck. Is there an isolator valve mentioned in the manual? If so, I can't find it. Any suggestions is appreciated.
 
May 17, 2004
2,277
Beneteau Oceanis 37 LE Havre de Grace
Some owners install a bypass around the heater to make winterizing easier. It’s possible that was installed on yours and left in the winterizing position. Some water heaters also have a mixing valve on the output to prevent scalding, and if that valve failed or were set too low then too much cold water would get put into the output.
 

NYSail

.
Jan 6, 2006
2,367
Beneteau 423 Mt. Sinai, NY
You should turn it off until you figure this out. Don't want to burn out the element. As David said, check the water heater and make sure the bypass for winterizing has been taken off and that water heater is actually filling with water. Make sure the tank is connected correctly and then work your way.... any mixing valve would be at the tank.
Good Luck
 
Jan 7, 2011
1,782
Oday 322 East Chicago, IN
As @Davidasailor26 said, check for a bypass. I winterized my boat the first year I owned it. The PO had 3 valves to bypass WH.

in the spring, I commissioned the boat, filled ranks, and turned on the WH. But no hot water. I bought a new thermostat controller, assuming it had burned out. Replaced it, and still no hot water.

Turned out I missed one of the 3 valves, so the water was still bypassing the heater :banghead:


Greg
 
Dec 2, 2003
507
Hunter 260 winnipeg, Manitoba
You may also have a thermostatic mixing valve on the outlet side which is meant to prevent scalding By mixing cold water with the hot. It may have become stuck in a position that prevents the hot water flowing. It can usually be disassembled and cleaned.
 
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Sep 15, 2013
577
Catalina 270 270 Mystic Baltimore
Agreed with NYSail. The boat was probably winterized and standard practice is to bypass and drain the water heater. The trick is to find the bypass valves. Sometimes the the input and output hoses are disconnected and hooked together for the winter. Doubtful on a boat of that size though. Also I hope your elements are still good after running them dry.
 

Mr Fox

.
Aug 31, 2017
142
Marshall 22 Falmouth, ME
Since you installed a hot water heater, you need to feed it hot water or it won’t work. Now if you had purchased a water heater you’d be all set;)


sorry needed a little grammatical humor in my day...
 
Apr 11, 2010
754
Hunter 38 Whitehall MI
Since you installed a hot water heater, you need to feed it hot water or it won’t work. Now if you had purchased a water heater you’d be all set;)


sorry needed a little grammatical humor in my day...
So true. Why would anyone put in a hot water heater. Hot water doesn’t need to be heated. A water heater on the other hand is perfect for heating the cold water.
Thanks for attempting to brighten the day :)
 
Last edited:
Jun 9, 2008
1,599
- -- -Bayfield
Remember that when you turn on the cold water faucet, the water goes right from the tank through the pump to the faucet. With the hot water side, there is the water tank inside the heater and that has to fill up first, before it can further reach your hot water faucet. So, be patient. Also, NEVER TURN ON THE HOT WATER SWITCH on the electrical panel until you are sure that the water tank is full of water and water is coming out on the hot side of the faucet. Turning on the switch without water will burn out the heating element and until that is replaced, you will never get hot water. Sometimes also in the winterizing process the pressure valve is opened to drain the HW tank and if not closed off, then it will just piss out water as you try to fill up the heaters tank. You should notice that your bilge is filling up though, or see the stream of water coming from your hot water heater. Some people are mentioning that you installed a new water heater, but I don't read that in your post. Maybe i missed something. If you did, then sometimes you have to make sure all the air is out of the system in including the heat exchanger. Usually an indication of this would be your engine over heating because there are hoses from the heat exchanger also entering the hot water engine side of the twin tank in the heater.
 
Feb 21, 2008
313
Hunter 33 Metedeconk River
Sailme88; could you add labels of inputs, outputs and parts? For instance, what is the white fitting on the upper right,
the fitting on upper left and the two silver ducts in the center. Also, how to winterize this set up? Mine looks a lot different.
Maybe mine is a hot water heater? LOL. Thanks
 
Jan 19, 2010
398
Catalina 34 Casco Bay
Sailme88; could you add labels of inputs, outputs and parts? For instance, what is the white fitting on the upper right,
the fitting on upper left and the two silver ducts in the center. Also, how to winterize this set up? Mine looks a lot different.
Maybe mine is a hot water heater? LOL. Thanks
OK, here you go.. Top right corner is a white barbed elbow with a RED tag near it. This is the cold water inlet. Directly below is the cold water 90 degree ball valve. Allows or stops water into the heater. In the middle is another 90 degree ( quarter turn) ball valve. Closed in the pic, it prevents cold water from mixing with the hot. Below it is the relief valve. Below the relief valve and above the cold water inlet is the hose barb ( silver ish) this is the hot water loop inlet from the engine ( heated antifreeze). Back to the top on the left is the hot water outlet (purple tag) with isolating quarter turn below it.. The valve below that is the tank drain valve with the antifreeze loop outlet just above.
IMG_8329.jpg
 

Jim26m

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Apr 3, 2019
470
Macgregor 26M P Cub Boo Mobile AL
@Digger54, did you ever find the issue? If not, can you post pics of your piping at the heater? A lot of folks are trying to help you.