Murphy was our dinner guest

What's wrong with this picture?

Last Friday, an hour or so before our dinner guests (the crew of s/v Ghost) were scheduled to arrive, I noticed that our heat pump was blowing cold air.  It had been working fine for weeks/months/years.  Until then.

Of course, with that timing there was no opportunity to look into the problem.  So we lit the Dickenson heater and went on with the dinner as scheduled.  And then when we went to bed, I put out the Dickenson because I don't like to sleep with it lit.

So this morning, it was not exactly warm inside Eolian...  50°F. That's pretty cold sleeping.

And so this morning I had some immediate tasks to attend to.  First was to relight the Dickenson.  Then to make Jane her latte, of course.  Then finally to look into the heat pump failure.

Here's what I believe happened:  Yesterday afternoon and evening were quite windy, and there was enough easting in the wind to have Eolian tight against the dock, surging back and forth against the fenders.  So how is this relevant?

Apparently the movement of the boat had the fenders squished against the outlet fitting where the chilled exhaust water from the heat pump exits, blocking the flow.  Blocking the flow momentarily would not seem to be a major issue.  But with a longer interruption there is a problem.  Recall that the heat pump is withdrawing heat from the water to heat the boat, chilling the water in the process.  With the flow blocked, the water froze in the heat exchanger, permanently blocking the flow, even after the outlet fitting was uncovered. 

When I started the heat pump this morning, water circulation began immediately.  And inspection of the heat exchanger showed that there was no leakage.

Now I gotta relocate those fenders.

Murphy was our dinner guest