Empty Hot Water Heater - Can I run my engine?

Oct 3, 2014
261
Marlow-Hunter MH37 Lake City, MN
We finally figured out where our leak was coming from and it's our fresh water tank. We've emptied it as much as we can and will not be using it until it's replaced. Unfortunately we also discovered rotted wood which will also need attention. dangit!!

There are two lines between the water heater and our Yanmar which circulate water to use the engine heat to heat up the water in the tank. Can we run our engine with out water in the hot water tank?
 

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Good question, but I think so. It's just like heater hoses in the air, no?
 
Oct 3, 2014
261
Marlow-Hunter MH37 Lake City, MN
Well that's kind of what I was thinking, but I haven't completely figured out that system and I don't want to do something $tupid. For the cost of a post here, I can find out for sure.
 
Oct 9, 2008
1,739
Bristol 29.9 Dana Point
Yes you can.

What you should not do is turn on the AC power to the water heater when empty. You'll fry the element quick.
 
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Dec 14, 2003
1,393
Hunter 34 Lake of Two Mountains, QC, Can
Ditto Skipper and Jackdaw. If you're still unsure, then disconnect the hoses at the engine and replace with a short length of hose thus eliminating the hot water tank circuit altogether. On my boat that would be hoses 1 & 2. Yours might be installed a little different. You will need to replenish coolant when reinstalling a new water heater as what is in the hoses now will be lost in the bilge !
 

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Oct 3, 2014
261
Marlow-Hunter MH37 Lake City, MN
Thank you, gents! You've confirmed my suspicions.

The PO warned me about turning on the electric water heater element without water in the tank. He learned that the hard way
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Yes, you can run your engine with an empty tank, it's a not issue. As has been said, just don't flip on the electric element..
 
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Likes: uncledom