Hot Water Heater - H2O not heated from running engine.

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Richard Ad
Posts: 58
Joined: Wed Apr 14, 2010 1:08 pm

Hot Water Heater - H2O not heated from running engine.

Post by Richard Ad »

2012- May 14th: I ran the engine for 45 minutes and didn't get hot water from the hot water heater. So I plugged into shore power and turned on the electric hot water heater element and got hot water. I talked to Seaward (heater company) and they said to feel the domestic cold water "IN" hose to see if it's warm. If its warm then the check valve at the cold water "IN" is stuck open and the warm water backed up toward the fresh water tank. They said the check valve will allow the hot water tank to create pressure and without this pressure the water won't heat from running the engine BUT the electric heating element WILL heat the water. Has anyone heard of this or experienced this?

One more detail; Last season I removed the Whale Connector (plastic quick connect) because it came off twice when the water pump was on and drained my fresh water tank into the bilge. I'm not sure if that connector had a check valve in it. I removed this before last sailing season and I got HOT water from running the engine all last season.

Richard / #329
R.B.
Posts: 233
Joined: Fri Jan 20, 2006 2:04 pm
Location: Ontario, Canada

Re: Hot Water Heater - H2O not heated from running engine.

Post by R.B. »

I had problems with the check valve in the whale connector too. And finally removed it. I have not had any issues with the hot water heating since then. If you are having issues with the engine, heating the water, check to make sure you don't have an air lock in the coolant lines heading to the water heater. There are inline valves close to the water heater to bleed the system.
Ralph

WOLFHELM
C350 #342
wolfe10
Posts: 587
Joined: Mon Dec 11, 2006 2:58 pm
Location: Ft Myers Florida

Re: Hot Water Heater - H2O not heated from running engine.

Post by wolfe10 »

Seaward's response makes no sense. If the check valve is at fault, you would have the same symptoms whether the water was heated by the engine OR by the electric heating element.

In addition to checking for an air lock, check for a kinked hose going to/coming from the water heater, particularly at the engine.

Brett
Brett Wolfe
C350 #180
"Vindaloo"
Ft Myers FL
Richard Ad
Posts: 58
Joined: Wed Apr 14, 2010 1:08 pm

Re: Hot Water Heater - H2O not heated from running engine.

Post by Richard Ad »

Hello Wolfe10; I agree, Seaward's response doesn't make sense to me regarding the required "pressure build" in the hot water tank when heating water from running the engine BUT not needed when the electric element heats the water. I questioned that and Lonnie (Seaward / Technician) assured me that is how it works. He also said it's most likely not an air lock because the expansion tank in the Universal engines are really good at purging any air. I opened the closed loop valve at the hot water tank and coolant flowed out so there is "at least some" coolant at that location. The closed loop hoses that go into & out of the water tank both are warm to the touch after running the engine. I don't understandstand Seaward's response that "tank pressure is needed to heat the water when running the engine". NOTE: after running the engine the water from the HOT faucet is warmer than the COLD faucet after but only moderately warmer.

If it's an air lock: I've read on other sites that running the engine with the fill cap off will purge the line of any air. I've also read that opening the two drain valves (one at the water heater and one at the thermostat) while the engine is running will purge the lines of air; but coolant will come out and it can be messy. My engine temperature is running right at 165-170F (readings from the gauge and infared thermo gun) so I have to believe my coolant pump and thermostat are working. NEXT STEPS: run engine with the coolant fill cap off (open), then feel the domestic water IN hose to see if heat is backing up the line. This will lead me to either an AIR LOCK or hot water heater tank CHECK VALVE.

Any comments and suggestions are appreciated.

Richard Ad / #329
djones
Posts: 36
Joined: Tue Jan 22, 2008 7:03 pm
Location: Oak Island / Southport, NC

Re: Hot Water Heater - H2O not heated from running engine.

Post by djones »

Richard,
My 2 cents to add please. Before thinking about check valves, etc., I suggest a simple test. With the engine running and up to temperature, feel the two small hoses attached to the thermostat housing. One should be quite hot, carrying the heated engine coolant out to the water heater. (The hose should be hot all the way back to the water heater!) That heat will be transferred to the water in the tank via the internal heating loop inside the water heater. The other small hose is engine coolant returning back to the engine, and it should be much cooler in temperature now that most of the heat has been tranferred to the water. Make sure this heat-tranfer process happening before concering yourself with the fresh water side of things. If you don't feel the big temperature difference between the two hoses, then the engine coolant isn't flowing in those hoses. Chase that first.

I have seen hoses collapsed, blocked, pinched, etc. that can cause this problem, as well as an air block. Lastly, it is not unusual that using the engine to heat the water would take longer than the much hotter electrical heater element. But, the engine will eventually heat the water to a hotter temperature than the electrical element would by itself. I think the electrical themostat cuts off at about 140 deg. F or so. If you run the engine long enough, the water temp will match the engine coolant temp, 160 deg. or more, very hot water!

Good Luck,
Don Jones, #13 "Onatop"
Oak Island, Southport, NC
Richard Ad
Posts: 58
Joined: Wed Apr 14, 2010 1:08 pm

Re: Hot Water Heater - H2O not heated from running engine.

Post by Richard Ad »

2012-05-29. Before leaving the dock for 3 days of sailing this Memorial Day weekend I ran the electric hot water heater. Sailed to my anchor destination and then I had hot water for that evening and next morning. By morning the hot water was mostly used up. I then ran the engine under load for approximately 6 miles (1 hour) and I had moderately hot water but I could run the full HOT water over my hand without blending some cold water and did not burn my hand. Hot enough to take a shower with the faucet turned fully to HOT. It was not nearly as hot as it used to get when I ran the engine nor as hot as my friend's C-350 when run under the same conditions.

NOTE: Before the weekend I changed the thermostat. I also removed the coolant hoses (at the engine) and put a hose extension on one side and a bucket on the other side, raised the one line to the companion way opening and with a funnel poured coolant mixture until 1/2 gallon came out and reconnected the hoses to the engine. The engine ran at 170F all weekend and the expansion tank level was un-changed.

SOME MORE THOUGHTS: 1.) could the coil have coolant built up on inside and restricting the total volume of coolant that is inside the coil? 2.) could there be air inside the coil? Air is not good at transferring heat. 3.) could my coolant engine pump not be moving enough volume through my hot water heater? 4.) could my fill cap not be allowing pressure to build?

Hopefully this is something simple that I'm just missing. Help is appreciated.
MorningStar

Re: Hot Water Heater - H2O not heated from running engine.

Post by MorningStar »

When ever I change the anti-freeze I have the same problem with the level in the make up tank not moving up or down when the engine reaches operating temperature. Solution is to bleed all the air with the bleed valve at the thermostat housing and let the engine cool down to cold. Remove the coolant pressure cap and add coolant until full. Replace cap. Run the engine for a couple of hours and then let it cool down completely to cold. Remove the pressure cap again and fill up to top, replace cap. Run the engine again for several hour to purge all the air and this should take care of the air in the system and the coolant makeup take should go up once the engine is hot and the water heater should work okay.
One more check, make sure the small opening at the pressure cap that leads to the hose for the make up tank is not plugged.
s/v Morning Star
#35
EnriqueDelgado
Posts: 1
Joined: Thu Jul 16, 2015 10:21 am

Re: Hot Water Heater - H2O not heated from running engine.

Post by EnriqueDelgado »

http://www.bestsellingreviews.com/Home/Water-Heater/
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