Nice thread, timely too.
I have a pair of Frigoboat (Danfoss 35 F) air cooled evaporator plate systems on my boat. One of them is not working. Since they are installed next to each other I can (somewhat) easily exchange the controllers. Both systems have LED trouble lights on them. Neither is showing system errors. I have confirmed that the the controllers both work on the functioning side and both fail to make the non-functioning side work. I tested the controllers with both power supplies, thermostats, and fans so I am convinced that none of those are at fault on either system.
On start-up the faulty system draws an appropriate amount of amps, usually creates a small amount of frost just after the capillary but quickly drops down to a very low amp draw and there is little or no circulation of coolant
after the initial pulse. The compressor
is running and doing some work (barely above ambient temp) but the high pressure line is not warm to the touch and there is no sound of circulation in the evaporator plate. In the past both systems have had similar failures very intermittently and have been "cured" by fully defrosting the system and then restarting -- typically good for six moths to a year. I had the side that is currently working looked at by a tech a few years ago when it last failed and he was unable to find the fault with it (he did put a gauge set on it but otherwise didn't tamper with it). The other side is still factory sealed. I have assumed that the previous faults were caused by blockages /contamination/ice. Based on that history
I suspect that there may be a more complete blockage now. But, perhaps the system has low coolant
... Or maybe something else?
I do not have a gauge set. I have a bottle of R134a and an automotive A/C recharge kit with an entirely inappropriate low side gauge. The system does not have a sight glass and I'm resisting the temptation to do the obvious.
Any thoughts on what the next step in testing should be?