Paul,

Frigoboat refrigeration with Danfoss Compressor controllers have an error code of 1 Flash from a LED across the "D" terminal and a "+" terminal on the  Danfoss Compressor controller. This is a low voltage alarm, and is a highly reliable indication of a battery bank, wiring or connection issue. This alarm does not lie. If you have this alarm, you probably have a wiring or connection issue somewhere. I am sure that your Frigoboat has a Danfoss controller.

The part you are describing is, I believe, the Carel IR33 Electronic Thermostat. I checked the manual on this thermostat and see no error code 1. I believe that the Carel IR33 Electronic Thermostat could be used with any Frigoboat system. Maybe it is possible that this Carel IR33 Electronic Thermostat is relaying the Danfoss error code. I don't know, but if it is capable and is doing so, the solution is in the first paragraph. I have attached the Carel IR33 Electronic Thermostat manual for your convenience. Please let me know what you find.