Water Heater Issue

[Clay Greene]

Hoping someone may be able to help out a C34 alumnus with an issue with the Seaward water heater on our C387.  We are getting only slightly warm water (although definitely warmer than the cold side) when we operate the water heater on AC as well as after running the engine for a considerable time.  I checked continuity at the AC breaker and that seems fine (low resistance with the AC breaker open) and replaced the thermostat but that made no difference.  Under engine power, the coolant hose in and the coolant hose out both get hot to the touch so it appears that I have coolant circulating through the hot water heater.  We also have a petcock on the coolant in fitting and coolant comes out of that without issue.  No problems with the engine overheating so the coolant circulation seems to be fine.  I suppose the heating element could have failed but that would not explain the lack of heating with the engine running.  Thoughts? 

[KWKloeber]

Hoping someone may be able to help out a C34 alumnus with an issue with the Seaward water heater on our C387.  We are getting only slightly warm water (although definitely warmer than the cold side) when we operate the water heater on AC as well as after running the engine for a considerable time.  I checked continuity at the AC breaker and that seems fine (low resistance with the AC breaker open) and replaced the thermostat but that made no difference.  Under engine power, the coolant hose in and the coolant hose out both get hot to the touch so it appears that I have coolant circulating through the hot water heater.  We also have a petcock on the coolant in fitting and coolant comes out of that without issue.  No problems with the engine overheating so the coolant circulation seems to be fine.  I suppose the heating element could have failed but that would not explain the lack of heating with the engine running.  Thoughts? 

Is 'considerable time" under load or at the dock/hook?

Do a continuity check with a multimeter across the electric element - to see if it's bad.  (disconnect the power wires to the terminals!)

[Stu Jackson]

Have you checked the condition of the hose between the heater and the engine?

http://c34.org/bbs/index.php/topic,3769.msg21253.html#msg21253

[Dave Spencer]

The fact that you aren't getting hot water with either AC or engine coolant serving as the heating agent suggests to me that there may be something amiss with the valve arrangement on your cold water in / hot water out.  Since the boat is new to you, there may be a valve open that you don't know about. This happened to a friend of mine on his "new to him" Beneteau a couple of years ago.  Those of us in cold climes set up a bypass valve for the heater so when we're winterizing we don't have to fill the hot water heater with anti-freeze.  The valve is set up so that cold water into the heater bypasses the heater and connects directly with the hot water out line.  So to winterize, I turn off the cold water in and hot water out valves at the heater, and open the bypass valve.  In my friend's case, he had accidentally left all three valves open meaning that the water in the heater was getting hot, but when he turned on the hot water, he only got a little bit of warmish water since most of the flow bypassed the heater and flowed directly from the "cold in" line to the "hot out" line.  Try opening your drain cock on the heater to see if the water is hot.  Then, look around for a bypass valve that may connect cold to hot water.  They may not be as obvious on your boat as they are on my boat as shown in the picture.

Let us know how you make out.

[Clay Greene]

Some good ideas here but in response:

1.  I am sure there is no bypass valve for winterizing. 

2.  I will check continuity at the heater element but even if that was bad, it would not explain the lack of heating under engine power. 

3.  I have not checked the condition of the coolant hoses leading to and from the water heater other than what I can see.  However, the coolant level in the reservoir is not dropping and I see no evidence of coolant in the bilge so I do not believe I have a leak. 

4.  On Sunday, we had to motor back for about 45 minutes, engine temperature got up to 180 and stayed there, and we had just warm water when we got back to the slip.  I did not check the temperature at the drain valve so that is something worth doing. 

[Jack Hutteball]

On our C34 there is a check valve in the fresh water line to the hot water tank so the water can flow thru the tank only one way.  Possible that you are getting a mix of cold and hot if it is running through the tank backwards.  Not sure if your system is plumbed the same way.

Jack

[Ron Hill]

clay : Your AC heating of the water should get it's temp up to almost 200F in about 20 minutes!!

[Clay Greene]

Thanks for your responses, everyone.  I went down to the boat last night and got steaming hot water after 30 minutes with the AC breaker on.  Looks like the replacement thermostat fixed the AC problem after all.  We're going out sailing this evening so we'll see if the engine side is still a problem. 

[2ndwish]

Clay- On our 380 ('97 model year), we had a lot of crud in the water heater coolant loop lines.  Looked like Dexcool crud. We had to replace the lines anyway (they were cracking). Blew it out and refilled the lines. The water heats faster now- although it always got hot. On the WB, the water heater loop is a bypass on the main coolant loop, so a problem there might not show up on the engine temp. I'm beginning to think that on boats "more than one problem" is the norm for debugging! Glad you found part of your problem.

[Clay Greene]

That's very interesting about the coolant loop being a bypass and not being integrated into the closed cooling system of the engine.  I've seen several other owners recommend detaching the coolant loop hoses from the engine and flushing them.  They seemed to think there was an air bubble in the hoses that flushing cleared out but either way it would address the problem.  That may be my next step if the engine heating still fails to work.  Thanks for mentioning!  (And I am glad to see that there is another former C34/current C380/387 owner lurking on the C34 site!)

[Stu Jackson]

1        That's very interesting about the coolant loop being a bypass and not being integrated into the closed cooling system of the engine.  I've seen several other owners recommend detaching the coolant loop hoses from the engine and flushing them.  They seemed to think there was an air bubble in the hoses that flushing cleared out but either way it would address the problem. 

2          That may be my next step if the engine heating still fails to work.  Thanks for mentioning!  (And I am glad to see that there is another former C34/current C380/387 owner lurking on the C34 site!)

Clay,

1   If there is an air bubble the engine would overheat.  Immediately.  That's why we promote the "How to Burp Your Engine" thread when folks mess around with ANY fresh water coolant hoses.

2    Yes, there are a lot of "systems oriented" skippers out there, all of whom are very welcome to join us here.  Great to have you all, and glad we can help.