Resurecting dormant 12V fridge compressor

[Reefmagnet]

I installed a new fridge into my boat about 7 years ago now and it was only lightly used for the first two years. I goofed up when I installed it in that the line between the evaporator plate and compressor passed under the manual bilge pump located in the same cupboard. As fate would have it, the pump was leaking slightly and dripping onto the foam insulation at the point where the aluminium evaporator tubing joined the copper tubing. As a result the aluminium tube developed pin holes through corrosion and the gas leaked out.

So, basically the system has been out of gas and out of service for the last 5 years. Rather than throw whole system out, I'm thinking of just getting a new evaporator plate installed and re-gassed. The compressor is a Danfoss BD-35. Electrically the compressor is functional but I'm concerned the internals might be suffering from a long period of un-use? Is this a possible problem?

[OzeLouie]

The leak will have allowed venting of air in / out over the 5 year period and that causes a lot of moisture (contaminate) to be deposited throughout the refrigeration system. This would be very difficult to rectify with any reliability. Suggest cutting your loses and replace the fridge. Perhaps your insurance may cover your loss?

[sailormed]

The refrigerant contains a lot of oil that is all over the internals of the compressor. In my opinion your installation is ready to use after the repair.

[Richard Kollmann]

Originally Posted by Reefmagnet

I installed a new fridge into my boat about 7 years ago now and it was only lightly used for the first two years. I goofed up when I installed it in that the line between the evaporator plate and compressor passed under the manual bilge pump located in the same cupboard. As fate would have it, the pump was leaking slightly and dripping onto the foam insulation at the point where the aluminium evaporator tubing joined the copper tubing. As a result the aluminium tube developed pin holes through corrosion and the gas leaked out.

So, basically the system has been out of gas and out of service for the last 5 years. Rather than throw whole system out, I'm thinking of just getting a new evaporator plate installed and re-gassed. The compressor is a Danfoss BD-35. Electrically the compressor is functional but I'm concerned the internals might be suffering from a long period of un-use? Is this a possible problem?

With nothing but a pin hole leak I would get and install a new evaporator assembly. Barrow or rent a two stage refrigerant vacuum pump. If you lost enough oil to worry about there would have been a large area of oil near leak location. Assuming you have servicing gauge set, R134a pure refrigerant and compatible ACME to AN hose fittings to connect vacuum pump to low pressure compressor service fitting connect and then turn pump on.

It is extremely difficult to remove moisture from Synthetic POE oil that in that Danfoss compressor. To boil the moisture out super dehydration is needed, this can only be achieved by keeping complete system including evaporator inside box at a temperature above 75 degrees F and no more than 100 degrees F for 12 to 24 hours. Recommissioning pin hole leaks is common and can be done without replacing filter dryer as pumping process will remove moisture in dryer. Correct refrigerant charge in a BD35 compressor is 3 to 5.5 amps of current when operated on 12 volts based a ambient temperature and compressor speed. The correct volume of refrigerant by weight depending on evaporator size is 60 to 100 grams so do not add refrigerant too fast or control module will prevent future compressor start ups.

[OzeLouie]

If you do decide to replace the evaporator (bad option! especially in Oz where you have to employ a certified refrige tech) at least make sure the copper to aluminium pipe connection on the new evap is sealed air-tight to prevent corrosion of those dissimilar metals in the future.. a common problem. And replace the dryer with a type 032 or 052 proper filter dryer.
Also note... if evacuating after fitting the new evap, it is essential to evacuate from both the low AND high side of the system to be sure of complete evacuation.

[Reefmagnet]

Well that's the problem in Oz. The cost of the re-gassing (which has to be done by a licensed refrigeration mechanic) sails pretty close to just throwing in a complete precharged system. The only reason for considering keeping the old unit is that it was barely run in to start with, and throwing it in the garbage goes against my grain a little bit. Besides, I got so ticked off with the cowboy that just re-gassed the damned thing without doing proper diagnostics despite being specifically requested to do so that I purchased a fibreglass cased portable fridge and threw it in the vee berth and which works very well - it's just a pain moving from the galley to the vee-berth all the time for the milk!


I was going to replace the evaporator anyway with one that includes a small freezer compartment and I can pick a place, time and (hopefully) competent and fairly priced fridgy to do the re-gassing

[Richard Kollmann]

Originally Posted by Reefmagnet

Well that's the problem in Oz. The cost of the re-gassing (which has to be done by a licensed refrigeration mechanic) sails pretty close to just throwing in a complete precharged system. The only reason for considering keeping the old unit is that it was barely run in to start with, and throwing it in the garbage goes against my grain a little bit. Besides, I got so ticked off with the cowboy that just re-gassed the damned thing without doing proper diagnostics despite being specifically requested to do so that I purchased a fibreglass cased portable fridge and threw it in the vee berth and which works very well - it's just a pain moving from the galley to the vee-berth all the time for the milk!


I was going to replace the evaporator anyway with one that includes a small freezer compartment and I can pick a place, time and (hopefully) competent and fairly priced fridgy to do the re-gassing

Sounds like an excellent plan to me but always get price to complete project up front.

[RaymondR]

Originally Posted by Reefmagnet

Well that's the problem in Oz. The cost of the re-gassing (which has to be done by a licensed refrigeration mechanic) sails pretty close to just throwing in a complete precharged system. The only reason for considering keeping the old unit is that it was barely run in to start with, and throwing it in the garbage goes against my grain a little bit. Besides, I got so ticked off with the cowboy that just re-gassed the damned thing without doing proper diagnostics despite being specifically requested to do so that I purchased a fibreglass cased portable fridge and threw it in the vee berth and which works very well - it's just a pain moving from the galley to the vee-berth all the time for the milk!


I was going to replace the evaporator anyway with one that includes a small freezer compartment and I can pick a place, time and (hopefully) competent and fairly priced fridgy to do the re-gassing

After a number of bad experiences with fridge techies I decided to just ignore all the BS and go DIY. I have found boat refrigeration to be a fascinating subject and am now quiet pleased that I was driven to doing my own.

[Reefmagnet]

Originally Posted by RaymondR

After a number of bad experiences with fridge techies I decided to just ignore all the BS and go DIY. I have found boat refrigeration to be a fascinating subject and am now quiet pleased that I was driven to doing my own.

Do you do your own gassing?

[RaymondR]

Originally Posted by Reefmagnet

Do you do your own gassing?

I do but use hydrocarbon based refrigerant.

[OzeLouie]

Originally Posted by RaymondR

I do but use hydrocarbon based refrigerant.

Interesting Raymond, have you had any issues with that refrigerant? Years ago we trialled several like Care 30, FR12 etc which were all propane/ butane blends and got some weird results especially at low evap temp when separating appeared to occur but the R600 products seem to have that sorted so interested in what you used and have found.

[Reefmagnet]

I got a feeling this is a stupid question, but are the CH frig gasses still flammable?

[RaymondR]

Originally Posted by OzeLouie

Interesting Raymond, have you had any issues with that refrigerant? Years ago we trialled several like Care 30, FR12 etc which were all propane/ butane blends and got some weird results especially at low evap temp when separating appeared to occur but the R600 products seem to have that sorted so interested in what you used and have found.

I have been using Hichill since about 2010. The one I'm using now is their Minus 30. I changed the system in the boat I have now in 2017. I have not had any problems with it so far.