Danfoss 101N0212 Controller -- 2 flashes, no fan

[Ryban]

I have a new 101N0212 controller that I hooked up to my compressor 4 months ago to see if the compressor still worked. I shorted the C and T terminals as suggested in troubleshooting guides, and the compressor hummed to life. I tried it a few more times, and it seemed to be running, though I didn't leave it on long enough to determine if the plate was getting cold. I didn't run it for more than a minute.

After that, I was no longer able to start the compressor at all by shorting these terminals. There are no mechanical indications of any start attempt, and I see the internal LED flash 2 times, immediately after shorting the terminals, and continue to flash 2 times, repeating for about a minute.

The information I have found tells me that this indicates "Too many start attempts or fan over current". Since there's no fan hooked up at the moment, I don't think it's the latter.

So what does it mean by too many start attempts? Though I'm not a refrigeration expert, it doesn't seem like it's attempting to start the compressor at all.

[Typhoon]

Hi Ryban

Try turning off the power to the unit for 5 minutes . Remove your diode so the only connections you have are your c and t , and your power . Check your power connections , make sure they are clean and in good condition , power it up again , see if goes .

Regards John

[Ryban]

I've left it off for much longer than 5 minutes before trying again, to no avail. I'll try cleaning up/re-cutting the power connectors though. I don't actually have a diode hooked up. I have the module connected to the compressor, but hanging loose so that I can see the LED on the circuit board inside. I believe this is a diagnostic LED used by the manufacturer, but it follows the same error pattern described in the troubleshooting section of the documentation. Blinks twice, repeats every 4 seconds.

[Typhoon]

Originally Posted by Ryban

I've left it off for much longer than 5 minutes before trying again, to no avail. I'll try cleaning up/re-cutting the power connectors though. I don't actually have a diode hooked up. I have the module connected to the compressor, but hanging loose so that I can see the LED on the circuit board inside. I believe this is a diagnostic LED used by the manufacturer, but it follows the same error pattern described in the troubleshooting section of the documentation. Blinks twice, repeats every 4 seconds.

As "module" do you mean something like a Merlin speed control device ?

If so, take it off , just have the power connected and the C and T bridged and see if it goes .

If it does not go after that , take a picture of the setup , that would clear it up a lot for me . What make is the system ?

Regards John.

[Richard Kollmann]

If there are no wires connected to module fan terminal F the LED code of two flashes should not happen.

[Ryban]

Originally Posted by ColdEh Marine

As "module" do you mean something like a Merlin speed control device ?

If so, take it off , just have the power connected and the C and T bridged and see if it goes .

If it does not go after that , take a picture of the setup , that would clear it up a lot for me . What make is the system ?

Regards John.

I don't have the external controller connected yet (an MT-512 17, which I think allows me to set temperature, and other program features). I have only connected the 101N0212 itself, with power only, and the shorted C-T. See the attached photo.

Edit: The wifi here on anchor is too weak to upload anything high quality, so I had to greatly reduce the image size and quality. Hopefully it's sufficient.

Originally Posted by Richard Kollmann

If there are no wires connected to module fan terminal F the LED code of two flashes should not happen.

Don't know what to say. I connected an LED across + and D/I to verify the internal LED was indeed giving error codes, and sure enough, I get the same two flashes on the external LED. The instructions I have that came with the controller say:

"Error code 2: Too many start attempts or fan over current. (Too many compressor fan starts in short time, or fan current higher than 0.5A)."

[Typhoon]

Wow , that has got to be the rustiest compressor I have ever seen ! Was it running at all ?

Did you get a start up with just the C and T and power connected ?

Crimp some ends on the c and t jumper , make sure you have a good contact .

Regards John.

[Ryban]

Yeah, it's a bit rusty. It definitely came to life 4 months ago though. I'd be surprised if it died during the short time it was running.

I added terminal connectors to the jumper and connected it, but am still just getting 2 flashes. I unplugged it from the compressor, and I get 2 flashes still. I plugged it back into the compressor while power was still on, and I got 3 flashes a couple of times, but it went right back to 2 flashes.

[Typhoon]

Sounds like your controller is done . Must be a fault in the fan drive circuitry. As Richard said you should not get a two flash fault if there is no fan connected . Do you have a spare controller ?

Regards John

[hzcruiser]

Originally Posted by Ryban

I added terminal connectors to the jumper and connected it, but am still just getting 2 flashes. I unplugged it from the compressor, and I get 2 flashes still. I plugged it back into the compressor while power was still on, and I got 3 flashes a couple of times, but it went right back to 2 flashes.

Did you ever get it work again? I'm asking because I received a brand new BD50F with 101N0212 controller a few days ago (from a reseller called Nautimarket in Italy) and it shows the same symptoms, two flashes on the LED with or without the fan, the compressor doesn't even try to kick in. The newer manual (fomr 2016) says 2 flashes now means:


"Too many start attempts or fan over current"


but even if I let it sit for an hour and then provide power to it, there is no movement. It's being powered by a fairly small power supply while it's on the bench, still capable of 4A. I'll try and hook it up to a bigger battery instead. But low voltage drop-out would at least causing the thing to start up or return a different error code, one would think?

[hzcruiser]

Originally Posted by hzcruiser

"Too many start attempts or fan over current"

For the record (and anyone reading this later), the compressor is working now, that I hooked it up to a proper LFP battery rather than a bench power supply.

Nevertheless, the fault LED still showed two flashes for about a minute until the motor kicked in, so something is wrong with the electronics, it seems.


It has a holding plate evap which I read on this forum is not really the best solution nowadays anymore. I guess I won't have a huge surplus of energy during the day but with a smart digital fridge thermostat / controller my plan is to automatically run it colder than necessary during the day and freeze the holding plate.


That way the compressor might not have to kick in at night (or much later) and more energy goes straight into the cooling system rather than into the batts first to be pulled out again a few hours later.

[Raphdiaz]

I had the same problem with a new compressor so i stumbled into this forum. my issue was once powering up i had 2 blinking lights as the fault code. i measured my voltage on my supply and it was 12.6V. i disconnected the fan, same error code. i disconnected the CPT thermostat harness and bridged C and T and the compressor did not fire up. i left the bridge on C and T and used an external 12V battery and the compressor started. i then went back to my breaker and realized i did not have my ground wire on a dedicated ground connection or i assumed it was grounded properly. i moved my ground to a more dedicated ground connection and the compressor and fan powered up with no fault codes, cold fridge, cold beer!

so to add to the trouble shooting of this particular problem, try adding a dedicated external battery and repeat all of the trouble shooting steps, if it powers up then go check your connections to your house battery.

[OzeLouie]

Originally Posted by Raphdiaz

I had the same problem with a new compressor so i stumbled into this forum. my issue was once powering up i had 2 blinking lights as the fault code. i measured my voltage on my supply and it was 12.6V. i disconnected the fan, same error code. i disconnected the CPT thermostat harness and bridged C and T and the compressor did not fire up. i left the bridge on C and T and used an external 12V battery and the compressor started. i then went back to my breaker and realized i did not have my ground wire on a dedicated ground connection or i assumed it was grounded properly. i moved my ground to a more dedicated ground connection and the compressor and fan powered up with no fault codes, cold fridge, cold beer!

so to add to the trouble shooting of this particular problem, try adding a dedicated external battery and repeat all of the trouble shooting steps, if it powers up then go check your connections to your house battery.

Bad power supply, the most common reason why these DC refrigeration systems fail.

Voltage drop test:



Using a good multi-meter connected to the negative and positive terminals (- & +) on the MDM as shown above, read the voltage before and when the compressor starts or attempts to start.

The voltage reading with no load, before the compressor starts is meaningless but do note that no-load voltage.

Next, continue to monitor the voltage as the compressor starts or attempts to start. If this voltage drops away by say a volt or more or below 10 volts then that is confirmation that most likely the battery or power supply cable is the problem and that the compressor and MDM are not at fault. Again with multi-meter, check again as above, from MDM back to the battery, testing at each terminal access etc.

[hzcruiser]

Yes, a good ground is always important. It seems those double flashes could be misleading or indicate more than what the manual says (as mentioned in my post #11).