danfoss compressor fridge, 5 flash fault persists in open air

[prosodyspeaks]

Hello, first post, hopefully not doing it wrong?!

i have a Waeco RPD 0040E 12v compressor fridge with Danfoss BD35F, bought recently second hand.

fridge worked fine to start with, after a week the compressor has ceased operation.
internal light continues to function
LED diagnosis gives 5 flashes (thermal overload)

fault continues after standing for 48 hours in open air.

what now? some kind of internal fuse or reset procedure? replace controller?

thanks for any help you can give!!

[dlymn]

answer: second hand.. The most common problem with compressors is voltage drop. Hit 11.99 volts and the compressor will contantly cycle on and off but not compress. this cycling, if left long enought will probably cause a thermal overload. The way to test this is to read voltage at the compressor when under operation, but that sounds like it's not gperatinal and so can't be tested.
also check fan operation and examine compressor cooling radiator for dust blockage.. thermal overload switches can be a mechanical device and are subject to faults.

[prosodyspeaks]

thanks, just noticed that with thermostat pins bridged the internal light does not operate, this have any relevance?

[Richard Kollmann]

On these variable speed three phase compressors a 3,4,5,and 6 LED trouble code can also indicate dirty electrical power from boat's electrical source. Before blaming the refrigerator unit Power electronic module positive and negative terminals with fused jumper wire direct from a fully charged battery.

[rourkeh]

The diagnostic for 5 flashes is
• Five Flashes – Indicates that the electronics heat sink has exceeded 212 deg F (100 deg C). This can be due to an overcharge of refrigerant, water in the system, or excessive ambient temperatures combined with a compressor operating under extreme load. A re-start will be attempted when heat sink has cooled to 170 deg F (80 deg C).
In my experience these compressors never go bad but the controllers fail all the time. I have replaced 2 in the last couple of years.

[prosodyspeaks]

Hi Richard, thanks so much for joining in!

i have been testing the fridge wired directly to battery (via fuse). all house electrics are off at initial breakers, only other battery activity is solar charge controller and VSR linking engine battery (active due to increased voltage from solar charge controller). Apart from killing all other battery outputs this is exactly how it was when first installed and through the week of happy operation.

voltage measured at fridge with fan and internal light running is currently 13.48 (panels live)

after initial week's perfect operation in sub-optimal installation (not built in, and with space for a little passive cooling but no fan) the unit failed, possible following turning thermostat to full (to try and make ice) or possibly after running the engine for the first time (both of these were in fairly quick succession)... obviously i don't know exact moment of failure as wasn't keeping a constant eye.

in case it's of any relevance the original installation was with pretty thin wire - i bought the unit second hand with no instructions and foolishly used the wire already attached. since having issues i've been reading and have replaced with 6mm (when was on a 4m run from battery) and now testing with 2.5mm around 1m from battery.

any thoughts?

[prosodyspeaks]

Originally Posted by rourkeh

The diagnostic for 5 flashes is
• Five Flashes – Indicates that the electronics heat sink has exceeded 212 deg F (100 deg C). This can be due to an overcharge of refrigerant, water in the system, or excessive ambient temperatures combined with a compressor operating under extreme load. A re-start will be attempted when heat sink has cooled to 170 deg F (80 deg C).
In my experience these compressors never go bad but the controllers fail all the time. I have replaced 2 in the last couple of years.

hi rourkeh, sorry think i was replying to richard when your post came through!

the unit has definitely cooled below 80C but 5 flash persists...

you mention water in the system - the unit is second hand of unknown provenance (former owner was getting rid in favour of a 'proper' 3 way absorption fridge haha!) and has likely been sat for some time, could this be relevant?

beginning to believe i've fried the controller - is there any repair or component diagnosis/replacement route i could pursue? i have very low budget and hunted for a long time to source the fridge cheap, a replacement controller will cost as much as i paid - i'm likely to simply be without refrigeration again

[170122]

Danfoss compressor will require 12V TO 24V RUN, check the voltage on the + and - next to the compressor, but let it cool down for few hours then you measure the voltage when the unit is trying to start.
do you have a water cool system? or a fan cooling, maybe a keel cooler? make sure the hot line leaving the coil is room temperature, if not check the fan, or the pump or clean your keel cooler.

[Richard Kollmann]

prosodyspeaks, My point in responding is to inform you the Danfoss BD35 is not a 12 or volt 24 volt compressor, so compressor volt meter readings are of no value to you. Also volt meter readings at the electronic module will not display a low voltage boot up spike that will prevent compressor from running unless maybe you have Superman's eyes or an oscilloscope. You are dealing with a modern electronically pulsed three phase two component part unit compressor with protection logic boot up circuits. If someone has connected voltage direct to compressor it can self destruct.

If you followed my troubleshooting instructions correctly by disconnecting all present electrical sources and then powered module direct from a 12.5 volt + independent battery. You will also need a jumper wire across C and T module thermostat terminals. Now if compressor does not run try another electronic control module.

[prosodyspeaks]

Originally Posted by Richard Kollmann

prosodyspeaks, My point in responding is to inform you the Danfoss BD35 is not a 12 or volt 24 volt compressor, so compressor volt meter readings are of no value to you. Also volt meter readings at the electronic module will not display a low voltage boot up spike that will prevent compressor from running unless maybe you have Superman's eyes or an oscilloscope. You are dealing with a modern electronically pulsed three phase two component part unit compressor with protection logic boot up circuits. If someone has connected voltage direct to compressor it can self destruct.

If you followed my troubleshooting instructions correctly by disconnecting all present electrical sources and then powered module direct from a 12.5 volt + independent battery. You will also need a jumper wire across C and T module thermostat terminals. Now if compressor does not run try another electronic control module.

hi again Richard, yes I've read a fair few of your posts to other people and have followed your instructions general and specific - I haven't messed with refrigerant and am aware that the ecu puts out 3 phase at that I won't be able to accurately monitor, I haven't tried to bypass controller... I will try disconnecting battery entirely so that it is only connected to fridge but am doubtful this controller will function again.

do you know anyone in UK offering similar check and replace service as you in USA?

[Triumphant]

Originally Posted by prosodyspeaks

do you know anyone in UK offering similar check and replace service as you in USA?

You could try Keto Ltd in Swanick Marina, Southampton Their contact number is 01489 583000. They handle Isotherm fridges which use Danfoss compressors

Let me know how it goes

John Q