Hi Ania, there can be many reasons a refrigeration system does not cool to expectations, so a bit more information is needed.
Is it part of the same system as the one in the galley, or a completely separate unit? Is this a new problem? Or has it never worked well? Is it a recent addition or original with the boat?
When you switch to on, what does it do? Have you measured the current it draws in the first few minutes, and again after a longer period? Watch it over the first five to ten minutes. I assume you have the thermostat set to the lowest setting, but try adjusting it to the other end of its range.
Does the plate in the freezer get cold, or just a little cool? Does the condenser get hot or just warm? Is the condenser air or water cooled?
Every observation helps in narrowing down causes.
I am sure there is a solution, it is just a matter of narrowing down to the specific cause.
The amount of refrigerant is quite small on boat systems. The easiest method to determine if a system is over- or under-charged is to feel the refrigeration plate. The coldest part will be where the liquid enters and evaporates. Then the mix will travel down the serpentine system and eventually return to the compressor. At that point the temperature should still be around freezing, so the evaporator plate should still have some frost on it. Finding out this temperature is important, if the returning solution is too warm then the system is most likely undercharged.
I bought a 2013 boat with a freezer that wasn’t cold enough. All it needed was a bit of additional coolant. There was no sign of a leak and the refridgerator technician thought it was likely never fully charged when new. I’m not sure if the previous owner ever used it. I called a marine refridgerator specialty company since I was home I. The USA. And I have heard conflicting advice in using special boat refridgeranr vs the car a/c refill kits. I figure if the right coolant is available why risk damaging the freezer based on questionable advice.
The temperature of the plate must be lower than the set temperature in order for heat to flow from the contents of the freezer to the plate. I would guess at 10 deg C lower when it has established running, but may get close to the set temperature soon after the compressor stops. So something in that range. Of course the set temperature is measured by the thermostat. If this is located on the plate, the plate will approach the set temperature, but the food temperature will be a bit higher. If the thermostat is located in the food compartment, but not on the plate, this gives better control of the food temperature.
I don’t have much experience with the refrigerants used in our small units, I would be more comfortable with butane or ethane, but they are not suitable on a boat. Refrigerants are identified by an R number, look for a label in your documentation or a sticker on the fridge. You can look up what they are on the web. They operate at different pressure for a given temperature range, so it is important to get a refrigerant that is suitable for your unit. Again, best if you have the documentation, or at least a model number so it can be looked up. Refrigerants are highly regulated due to global warming potential and the ozone layer, so the mechanic has to ensure none escapes during servicing. Not generally a job for the amateur.
The tech needs to check for leaks before just topping up if low refrigerant pressure is thought to be the cause.
On the Jeanneau 51 optional freezer in utility room isn’t cold enough to freeze on our boat. Is there solution for that? Thank you
Ania, I think you will find the option is for a top loader fridge in the utility room not a freezer. We took this option and keep the temperature higher as we use it for all our bottles and cans of drinks.
There was an option for a freezer drawer in the galley with an ice maker running on mains power. Jeanneau changed this option for us to a 12 volt freezer drawer but without the auto ice maker, we just use plastic ice cube trays.
The front opening fridge is good but ours was not installed properly, when the front wooden door was closed the magnetic fridge door behind it was not and it used to overwork to compensate and freeze up all the time. We adjusted the mechanism that holds the wooden door to the fridge door and now it’s ok.
any idea what that plate's temperature supposed to be? Its probably size of my laptop 13 inch or so.
Generally you want the return temperature to be 0c. It should not be colder than that but most of the evaporator plate should be frosted. This is just a rough guideline, my plates are Vitrifrigo and they mix the return and supply lines together so it is hard to get the exact temperature
Don't overlook the possibility that you simply need to replace the thermostat. I thought maybe I had lost some charge due to the freezer not freezing and the beer in the fridge not being cold enough when set to a 7. The thermostat was hard to turn this spring but got better with WD40. However the switch wasn't working quite right when I compared it to a new unit. Changed the thermostat and the freezer works well (beer had Ice in it when trying to quickly cool a few cans). The fridge now keeps all beverages quite cold...
--Craig 2004 Sun Odyssey 40DS Summer Breeze (makes me feel fine)