Fridge Failure - Danfoss BD35F motor start failure

[OzePete]

Originally Posted by Richard Kollmann

cgebluewater
Now I hope you understand It was a foolish and uninformed idea to let out refrigerant.
Richard, when are you going to explain what causes the suction line to sweat / frost if it wasn't over charged? Still waiting!!
Richard, may I suggest you talk to someone who actually understands capillary refrigeration systems and get them to explain to you why a sweating or frosting suction line can only mean one thing ... TOO MUCH GAS!
This is one of the most basic things a hands on fridge tec / engineer learns so suggest you ask around.
The only time I have seen an exception to this basic rule was when a capillary housed within the suction line leaked internally, but a very rare happening

I still recommend you only need to add refrigerant to achieve proper amperage draw of 6 psi to get the refrigeration performance you need. Then in a month or so have a service tech check system out. It is a little late to do the non destructive moisture check I recommended first. As a beginner in refrigeration this should be a lesson to follow the non destructive advice given first. Your units symptoms never indicated too much refrigerant.

There are only two things to worry about after getting system amperage up to 6 amps:
Your origianal performance was caused by a refrigerant leak.

Moisture freezing and thawing in capillary tube.

You may notice I never add Ha Ha or Lol to my serious recommendations.

Ha Ha Lol and all that jovial stuff.. (Well someones got to be happy! )
Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[Richard Kollmann]

Pete I give up, you can take a horse to water but you can not make him drink. Condensate on return line and no frost has now proven to be bad advice by letting out refrigerant when all other facts indicate low on refrigerant or moisture blockage. Theories based on a guess instead of known facts are dangerous as this boater just discovered. In an emergency situation a boater in trouble needs a solution not a suggestion to carry additional refrigeration tooling.

Now after the damage is done I would call on the Bahamas net and ask if another boater could help with five ounces of 134a refrigerant and a 134a to Freon servicing hose. Gauges and vacuum pumps are not necessary for emergency repairs. With ambient temperature in Bahamas now and compressor running at 3500 Rpm 6 amp sustained for the first 30 minutes is close enough. After two hours amperage will stabilize when plate is frosted over between 5 and 5 1/2 amps.

[cgebluewater]

Originally Posted by cgebluewater

Richard,
Can you tell me what the difference is between a AB "Power Plate" and a holding plate. ?
In one of your posts you mentioned it acts more like a standard evaporator. Does that mean it is some sort of hybrid between a standard evaporator and a holding plate ?

Can you please describe what the "Power plate" should look like when I do get it running properly ?
Should it completely freeze like a holding plate ?
Just frost up like an evaporator ?

Also I am beginning to think that the unit may not have ever been working correctly since we bought the boat. I have never seen the Power Plate frozen and I am not even sure a had seen it fully frosted up. But it did seem like it stayed much colder. The main reason I started all this was because it seemed a lot less cold and it was cycling on and off which I now wonder if it may of been due to heat considering it is mounted in the engine room.

Richard,
"After two hours amperage will stabilize when plate is frosted over between 5 and 5 1/2 amps.


It looks like this comment within your post to Ozepete is the short version of the answer to my post above. Would you be willing to give me your more expanded version of an answer to my questions about the AB power Plate.

I would also like to express my thanks to you and Ozepete for being so willing to spend your time giving boaters (me)your time and valuble advise. I completey understand that properly diagnosing a problem without having a trained person to work with as well as the equipment needed is a hit and miss proposition. I really appreciate all that both of you have tried to do to help me get this resolved.

[Richard Kollmann]

Cgebluewater, Thermo plates, Power plates and holding plates are all evaporator plates. The evaporator in a refrigerator is where liquid refrigerant is converted to as gaseous form of vapor absorbing heat as it changes. If a compressor has available surplus energy holding plates are sometimes used to store that surplus energy for use later. Power and Thermo plates store only small amounts of energy. Of all the different types of evaporators the standard evaporator maintains the best even control over box temperature.

Power and thermo plates help to smooth out the compressor stop and start run times but store very little Btu energy.. These small 12/24 volt compressors generally do not produce surplus Btu to store in holding plates unless boat is equipped with alternative sources of power from Solar or wind generation systems.

As far as a blue-water sailor like yourself is concerned it is only on the first day when refrigerator system is turned on will you see a difference in the different evaporator types. The standard evaporator begins to collect a very thin layer of frost after 15 minutes compressor running time. Thermo and power plates will take a longer running time to develop a frost cover. Holding holdover plates designed for freezing temperatures with cap tube flow control will take from 2 to 24 hours to freeze all of the eutectic solution, for this reason large holding plate systems use Thermo Expansion Valves instead of cap tubes.

[john61ct]

May be technicall true but in my experience usually evaporator is used to distinguish the thinner style from proper holding plates.

Originally Posted by Richard Kollmann

If a compressor has available surplus energy holding plates are sometimes used to store that surplus energy for use later.
…
These small 12/24 volt compressors generally do not produce surplus Btu to store in holding plates unless boat is equipped with alternative sources of power from Solar or wind generation systems.

I can't imagine how a compressor can have "surplus energy".

Even without alternative sources, a system can be designed around holding plates where the compressor is driven by AC power, directly off an engine, or with these 12V compressors, powered by an alternator or two.

And even just running off a DC battery system with solar, regardless of "surplus" or not some claim to have repeatable test data showing holding plates are more efficient than (thin) evaporators, everything else being held equal.

I'm sure someone here could provide a link.

Where budget or icebox space are limited and/or weight is really at a premium I agree evaporators have an advantage.

[Anjin]

As the original poster for this thread, I just wanted to update how things worked out. My guests arrived today bringing with them a new controller. Took about thirty minutes to swap out the old for the new. The fridge/freezer started working immediately and the system has pulled the temp down from ambient to where it ought to be.

Many thanks to everyone for the education. To Richard and Pete, special thanks - you may disagree but your discussions are enlightening to the those of us that are new to this. Refrigeration is no longer a mystery to me. My system may suffer another failure but I will hopefully have the tools, spares, and knowledge to tackle it because of the contributions from you experts.

Thanks again -

- Art

[OzePete]

Originally Posted by Richard Kollmann

Pete I give up, Promise! you can take a horse to water but you can not make him drink. Condensate on return line and no frost Richard, read post 53... there WAS frost reported on the suction line, so I ask again can you please advise how this frost could occur on the suction line if the system was not over gassed? Or will you yet again divert from this issue to yet again attempt to discredit my attempt to help a member. has now proven to be bad advice by letting out refrigerant when all other facts indicate low on refrigerant or moisture blockage. Theories based on a guess My advice is based on 55 years actually involved hands on in the design, engineering and building of many thousands of refrigeration systems, not just relaying information gleaned from others!instead of known facts are dangerous as this boater just discovered.

In an emergency situation a boater in trouble needs a solution not a suggestion to carry additional refrigeration tooling. My offer to this member is open to him. His system obviously has other issues, most likely contaminated by moisture, air or incorrect refrigerant and the best now is for him to evacuate the system, fit a new filter dryer and recharge with clean R134a

Now after the damage is done I would call on the Bahamas net and ask if another boater could help with five ounces of 134a refrigerant and a 134a to Freon servicing hose. So you are suggesting that adding refrigerant to a system that would not function when it was over charged then purged (as evidenced by frosting on the suction line) is going to fix it? Richard, really you need to talk to someone who services refrigeration systems. Gauges and vacuum pumps are not necessary for emergency repairs. With ambient temperature in Bahamas now and compressor running at 3500 Rpm 6 amp sustained for the first 30 minutes is close enough. After two hours amperage will stabilize when plate is frosted over between 5 and 5 1/2 amps.

Cheers, OzePete Ozefridge | 12 Volt Refrigeration Systems

[Richard Kollmann]

Pete, Now there is no way to explain Cgebluewater's no cooling at all after following your instruction to keep letting out refrigerant. I suggest you discuss this with your own experienced technicians.
I believe we should offer help that is constructive in emergency situations like this one by not going back to refrigeration school 101.