fridge regassing?

[steveghoward]

have an ancient danfoss unit on my boat which has worked well for years but now seems to have given up.

When I come to start the fridge, the compressor clicks a few time then, nothing. I still have the original instructions and, on the troubleshooting page, states that if this happens there is not enough power to kick start the unit. I charged up the batteries on the boat till they were bouncing and tried again, but the same effect happened.

In discussion, a refrigeration engineer said he thought it was a lack of gas and the unit needs regassing. Any thought please? Is this possible or is a new unit needed?

Thanks in advance

 

[2Tizwoz]

'A really good and much under rated feature of the Danfoss BD35 and BD50 compressors are their inbuilt diagnostics function. Before doing anything else with a 12v or 24v fridge that is not working is make sure you test the controller on the Danfoss BD35 or BD50 compressor. The following testing procedure must be carried out.

1. Turn off the breaker (or remove the fuse) supplying DC power to the system.

2. Use a small circuit to link out the thermostat terminals (C & T).

3. Next, connect a small LED to the small + and the D terminals.

4. Turn on the breaker (or install the fuse) to the system watching the LED as you do so.

5. If the compressor fails to start the LED will flash a number of times every four seconds.

Note: The fault code will only be shown when the compressor fails to start or stops.

Interpreting power supply results
Led flashes once LOW VOLTAGE, This means the voltage is falling below the minimum required at start up (10.5v for 12v systems)

Led flashes twice This means there is an error with the fan which is drawing more than 1 Amp and causing too much resistance to the compressor on start. Remove the fan terminals and if the fridge starts replace the fan and problem solved.

Led flashes three times Compressor has a start error, which normally means indicates that the control unit is faulty.

Led flashes four times Compressor overload. System has a blockage, possibly moisture that has entered the refrigeration system or the compressor has siezed

Led flashes five times Electric overload. Again this would suggest that something serious is wrong with the system and you should contact your local refridgeration engineer.'

'General Trouble Shooting Information
You can accomplish the tests needed but it would help to know the model Danfoss compressor you have. It will be a BD2.5 or BD3 or BD35 or BD50 compressor. I would suspect a battery voltage or boat wiring problem first and next the fan is drawing too much current. This problem will not be caused by refrigerant circuit unless someone has added refrigerant to system.

Test procedures are listed below.

This is a general troubleshooting overview of all Adler Barbour Danfoss compressor models.
Adler Barbour No Start or Compressor Shut Down in first two minutes.

Failure to complete a start up cycle is a common report on the Danfoss BD compressors. These 12/24 volt compressors have a brushless motor inside that is controlled by an external electronic module. There have been many different upgrades to these modules through the years so the control functions do vary from one series to another. The job of the module is to cause the motor armature to rotate at a given speed and stop the compressor if one of these operating conditions exists:
• Low voltage
• Fan circuit overload
• High amperage overload
• Compressor temperature below freezing

Some modules may have other functions, I believe the first three are common to all Danfoss manufactured modules used on BD compressors.

The report is that the compressor fails to start. As in all troubleshooting, you start with the simplest nondestructive testing first. If the system operates normally at times, this will rule out a refrigerant flow problem and therefore not require a refrigeration repairman.

Low voltage is the most common cause of start up problems. Low voltage can be traced to low battery voltage or the boat’s electrical circuit. The only way to insure that it is not a voltage problem is to connect a full charged battery directly to the electrical module with proper sized correct polarity jumper cables. The older model BD2.5 and BD3 compressors can indicate a low voltage fault with a LED if one is installed between module terminals C and D. Newer compressors BD35 and BD50 have a full function computer chip like your automobile. You can learn more about LED trouble shooting by viewing the slide show on my web site. There are several sections on all these compressors in my 12/24 Volt Refrigeration Manual.

The fan circuit overload will stop the compressor if the fan is faulty. There is a separate set of 12 volt + and - terminals on the module that powers the fan for cooling when the thermostat closes. This fan circuit on older units is limited to a maximum of one amp and ½ amp on BD35 and BD50 compressor modules.
To eliminate this circuit as a cause for a false compressor start, disconnect the fan wires and any other units connected to these terminals. When eliminating the fan make sure that the thermostat wire is not removed from C terminal on the older models.

High amperage overload: The first thing to check is to see that there is adequate air flow through the condenser coil, see if the fan running or could dust be blocking the coils. To test for overload connect a 10 amp scale ammeter in series with the power wire to the module and watch the start up and running amps. If the start amps exceed 9 amps or the running amps are above 7 amps, there is an overload. An amperage overload indicates the compressor is faulty or if recently serviced with refrigerant there is a refrigerant problem.

The module is more likely to fail than the Compressor but WARNING, do not install a new module on a compressor that test bad with the ohm meter.
The best test to determine condition of the compressor field windings is to check their resistance with an ohmmeter

I will describe the electrical resistance test of the compressor as best I can for the 12 volt BD2.5 compressor. If the compressor checks out the next thing to do is get the module checked Frigoboat will test it for you.
Resistance between terminals 1 and 2 is 0.2 ohms.
Resistance between terminals 4 and 3 is 0.2 ohms.
Resistance between terminals 2 and 3 is 3.5 ohms.
Take care in removing the connector plug from the compressor.'

From a couple of websites. If you're lucky the problem may be an electrical fault leading to low voltage at the compressor when it tries to start. The built in diagnostics may indicate that you have that problem.

A shortage of gas shouldn't prevent the compressor from starting. Compressor failures are apparently uncommon but do occur.

http://www.kollmann-marine.com/phpBB_old/index.php This is the Kollman Marine website which specialises in these compressors.

 

[pvb]

A shortage of gas shouldn't prevent the compressor from starting.

I think that's the important bit.

 

[omega2]

Uncouple it and turn it upside down for a minute or two. Take the beers out first.

 

[vyv_cox]

have an ancient danfoss unit on my boat which has worked well for years but now seems to have given up.

When I come to start the fridge, the compressor clicks a few time then, nothing. I still have the original instructions and, on the troubleshooting page, states that if this happens there is not enough power to kick start the unit. I charged up the batteries on the boat till they were bouncing and tried again, but the same effect happened.

In discussion, a refrigeration engineer said he thought it was a lack of gas and the unit needs regassing. Any thought please? Is this possible or is a new unit needed?

Thanks in advance

I have no knowledge of the subject but my son has a great deal. These are his words:
assume this is a danfoss BD2.5 compressor. Usually this would be a mechanical failure in the compressor or the electronic unit for the compressor most likely the electronic box. This is assuming good voltage at the terminals of the electronic unit and that the connector to the compressor is correctly plugged in and free from corrosion. I would try a new electronic unit as a first try if available but they may be more expensive than a new bd35f complete compressor. Probably best to look at a new compressor or complete system it is likely that if it's that old it is not worth spending more money on obsolete equipment. Certainly I don't believe it is a gas issue as the compressor would run normally and just not cool if it was low on gas. Hope this helps. Owen

 

[Mike388]

Hi I see this is an old post but perhaps someone will read it. I have an old figoboat system that has stopped cycling and seams to be loosing a lot of power. The controler is frigoboat E250154 which doesn't have the same terminals to test as in TF+CC - I am trying to find out if it is a controler problem thermostat or gassing ......
If I turn the thermostat down to 0 it turns off and when I turn it back on comes back on, however after that if I turn the setting down 2 or 3 it does not turn off even if it has been running all day)The fridge was installed a purchased from holland ... I purchased the boat last year. Also have found pipe and gauge to add gass so I presume the previous owner did his own re gassing.
I also seem to get a difference between being on shore power (as in the fridge gets colder than on battery power even though the batteries are good)