Salon heater thermostat

[Pour Excuse]

Hello all
Just returned from my cold 1997 400da
The boat is winterized but I leave the salon heaters set at 40 and use a bilge heater that is keeping the bilge at 40. When I arrived yesterday it was 24 in the cabin and both thermostats were blank displaying “- - - -“. When I opened the bilge door the temp came up in the salon and when the cabin temp came up to 32 degrees the thermostat display registered 32 and he heaters began to function
It is 1F this morning and the remote monitoring is showing me that these heaters are not functioning and the Solon is at 20 degrees.
Is it possible that these thermostats will not call for heat if it is below 32 degrees?
Any arctic knowledge of these thermostats sent my way would be appreciated.

 

[dtfeld]

Are you using the Marine AC with reverse cycle heat? If so, there gets to be a temp, i think around 40 deg they no longer work.

Basically you are taking heat from the water and transferring it to the cabin. The raw water is cooled and since it's already just above freezing, you cant pull much more heat out without freezing it.

You'll need electric heaters.

 

[bbwhitejr]

Are you using the Marine AC with reverse cycle heat? If so, there gets to be a temp, i think around 40 deg they no longer work.

Basically you are taking heat from the water and transferring it to the cabin. The raw water is cooled and since it's already just above freezing, you cant pull much more heat out without freezing it.

You'll need electric heaters.

I would think they would still run and just not produce any heat. I think the 40 degree mark is the bottom. Below that you get nothing, but I would think the unit would still operate. Electric heaters will be the way to go.

Bennett

 

[b_arrington]

Agreed that these reverse cycle units can't provide heat at low temperatures. Depending on the specifics of the model's operation they may have seawater temp sensors that blink when the temp is too low.

Also agreed you will need an alternative heat source - either electric heaters or install a diesel heater like a Webasto or similar. Folks that boat in the PNW routinely install diesel heaters.

The guy that runs the SeaBits website (he's in the PNW) recently posted a fairly long but very good article on his heating system and how he upgraded it. Might be worth a read. https://seabits.com/hurricane-chinook-hydronic-heating-system/