30th Jan 2019, 02:37 PM #1
Waeco CF80 Frig Freezer Operating and Fault or Problem Repair Notes
Waeco CF80 Frig Freezer Operating and Fault or Problem Repair Notes
Some operating notes, and hints for repair, gathered from personal experience and multiple sources.
These notes may also be useful for other sizes and makes of portable frig or cooler unit, but be cautious about different types.
Please be aware that the following is derived from my experience with one CF80 (with Danfoss BD50) unit, and a Danfoss BD35, and without access to any official Waeco Repair Manual or Official circuits. I have never seen an official Waeco Service Manual, if such a manual actually exists.
This Waeco CF80 is relatively well made and designed.
The Danfoss compressor is very reliable.
Most problems and faults with this unit are repairable.
Go slowly, have confidence, and good luck.
As you pull down the unit for investigation or repair, take plenty of photos beforehand, and mark all internal connectors with coloured marker identifying “dots”, before taking apart.
You will find it indispensable to have two saw horses on which to do any work on the unit.
I do not claim that these notes are error free, and you should allow for this.
Use these notes in conjunction with other web sourced notes.
01 Waeco CF80.jpg
02 Waeco CF80 Spec.jpg
Waeco User Manual
This Waeco manual is quite good, and needs to be read twice.
The Danfoss compressor manual also requires a second reading, as it needs to be digested slowly.
I am not aware of any Waeco Service Manual.
Waeco User Manual CF80.pdf
Official Waeco Service Manual?
I am not aware of any such manual or service notes, and would be interested to hear from others about this aspect.
Caution – this unit has AC mains connection.
My CF80 is a 240 V AC and 12 or 24 V DC supply unit, with dual zone; Waeco call this a CF80-AC.
It is similar to the next size up, the Waeco CF110-AC.
This type unit was discontinued in about 2015, and can still occasionally be found for sale in 2018, but has been in service by users for over ten years, and so there must be very many units still in use.
Caution – There are a lot of different Waeco CF frig freezers, all with different electronics. Information in these notes may not be applicable to your CFxx unit, other than the generic CF80.
Caution – this unit apparently has a few variants; be careful when ordering parts, or using parts from other frig units. Two known variants are Single Zone (Frig or Freezer, and Dual Zone, Frig and Freezer. A Dual Zone unit can be converted to a Single Zone unit by simply removing the plastic separators between the freezer and frig compartments.
My CF80 unit is a technical (as distinct from owner “usage”) “Version B”. The version type is printed on the product sticker on the side and or on the bottom. I believe that Version A had a “Turbo” switch; Version B does not have this switch.
This CF80 unit uses a Danfoss BD50 compressor and Danfoss 1010500 control unit.
An official Danfoss (now SECOP) brochure is available online for installation and operating notes. It is a very good document with a lot of information. You need to read it at least twice.
Waeco has added two extra proprietary PC boards to the basic Danfoss controller, and all work together in the CF80, and all must be in circuit for full operation.
The frig can be made to work without the two extra Waeco boards, but with reduced facilities.
In particular, there will be no thermostat action without both boards, and Danfoss controller terminals “C” and “T” must be linked, or the EMERG switch activated, and then the compressor will run continuously down to a temperature of approx -18 degrees C.
Quick Fault Analysis
If you are reading these notes in order to fix a fault, then you need to know that there is a break point beyond which it is not economical to repair, and it may be better to buy a whole new Frig Freezer.
The Danfoss Compressor is very reliable, but Waeco Approved Repairers will tell you that it does occasionally fail. A complete new Danfoss Compressor and Controller unit is expensive, and even the Danfoss controller is expensive.
It is possible that your fault may be elsewhere in the CF80.
A quick check to determine if the basic compressor is still working OK is to connect the “C” and “T” terminals on the Danfoss controller, then apply power to the CF80.
Remove the connection and the compressor should stop.
If this turns the compressor on and off, then it may be worthwhile continuing to fix the CF80.
If there is any doubt about the other connections to the Danfoss controller, remove all except the battery connections, then test that you have 12 volts at the controller terminals with a multimeter, then connect “C” and “T”.
The compressor should run.
You can also make the above test by switching the EMERG switch from Normal to Emergency.
If this test does not work, then it may not be worthwhile economically to continue.
This test may be done in conjunction with having a test lamp across controller terminals “D” (alarm) and “C”, so that any internal Danfoss alarms are observed. Consult the Danfoss brochure.
The test to connect “C” and “T” should be carried out in all cases of fault, if only for reassurance.
The frig can use AC mains or DC from 12 or 24 V batteries, and both sources can be switched on at the same time.
Priority is given to mains operation, and the Danfoss controller switches to this when available, and back to DC if mains is lost.
This “mains available” is sensed internally by the Danfoss controller, and also separately by the Waeco Main and Top display boards.
If the Main and Display boards are not present, and a thermostat across controller terminals “C” and “T” is used instead, “mains priority” is still used by the Danfoss controller.
I suspect that when on Mains, the CF80 has a slightly different compressor ON/OFF profile, for faster cooling. I am not sure about this.
When the AC power cord is connected and mains is available, the Danfoss controller is always “live”, irrespective of whether “ON” is selected on the top control panel.
Similarly with a DC connection, the Danfoss controller is always “live” to DC.
If both mains and DC are connected, the Danfoss controller is “live” to both AC and DC.
If the frig is operating on mains, and then mains is lost, there is a one minute delay before the frig switches to DC, to allow for short mains interruptions. During this time, the compressor fan (only) will continue to run. This is controlled from within the Danfoss controller unit.
If the frig is operating on DC, then mains becomes available, the compressor stops, then starts again after a few seconds as the Danfoss unit “tests” the DC, then operation continues from DC.
If the frig is operating from DC and it is interrupted, then the compressor just starts again a few seconds after DC is connected and “tested” again.
When DC is first supplied to the CF80, via the DC plug, and mains is not available, then all LEDs flash.
When mains is first supplied to the CF80, via the AC plug, and DC is not available, then all LEDs flash.
There is no ON switch as such for the Waeco CF80, the Danfoss controller, or for the compressor.
A switch could be placed into the DC power lead, or indeed the mains lead, but is not required. If a DC switch is added, the Danfoss booklet alerts the user that it must be rated accordingly, ie able to switch 7 amps DC.
The total CF80 DC current drawn when the frig is OFF (via the Display Panel), and when battery is available, is approx 0.08 amp.
The CF80 draws a little DC current even if OFF; it must draw a little current to be ready to switch ON via the electronics of the Display Board, ie the Top Display Board is always DC “live”, even with LEDs and Display OFF.
When operated from AC, and with no DC available from the battery, the Main Board and Top Display Board are DC live, and powered from the Lamp output “A” of the Danfoss Controller.
This does not affect the operation of the CF80 frig Lamp, which is always available, even if the CF80 is OFF via the Display Panel.
The total DC current drawn from battery when the frig is ON varies between 3.5 and 7.5 amps depending on multiple factors.
I suspect that the small wire (yellow in my case) piggybacked onto the +12V DC crimp connector on the Danfoss controller and then fed to Main Board pin 1, and then onto the Top Display Board, is not for power use, but for battery voltage sense by the microcontroller U1 using an internal program. I am not sure about this.
Power Leads, and Internal Voltage Tests
The DC power connection is probably the cause of most problems with these types of frig, with voltage drops across inadequate cable and dubious connections.
The DC connection has to be close to perfect.
When the frig is powered up, or when the compressor turns on in its refrigeration cycle, the Danfoss controller initially checks the DC supply voltage under load of the motor, and if the battery is low, or if the cables have too much voltage drop, then the Danfoss controller will then not run the compressor motor, other than the initial start-up test.
If the DC voltage rises (eg the vehicle alternator starts to charge), and battery condition is tested again as acceptable, and the CF80 will then start up and run normally.
This “re-test” and “switch back on” is automatic and cyclic.
The 12 and 24 voltage cut-out (switch off) and cut-in (switch back on) is user settable.
I use the “LO” setting, with “switch off at 10.1V”. This will not hurt a battery and gives the longest time running.
Early versions of the CF80 have the DC voltage cut-out settings by slide switch on the power input panel.
Avoid using the fitted cigarette plug if possible and cable the frig directly to the battery via one only fuse or circuit breaker. There is no DC fuse in the CF80, either in the case or in the Danfoss controller.
There is DC polarity protection in the Danfoss controller which will blow your fuse or throw your breaker.
Cable the frig using as large a diameter cable as is practical for your situation.
If you have a long cable run, cut the supplied DC cable short, eg 500mm, and run the main cable feed in 13 or 16 mm2 copper cable.
Choose larger cable size rather than smaller.
The Danfoss document has a cable choice guide, but you should use this as a starting guide only.
Be aware that “auto” type cable diameter specification includes the plastic sheath, and is mostly unsuitable and irrelevant.
Obtain your cable from Jaycar, Altronics, Springers or other similar quality specialist providers.
Crimp your connectors rather than solder them. Obtain good quality correct size crimp connectors from the above suppliers.
Use the correct crimp tool.
Caution about buying crimp connectors and cable from markets, which are generally of lesser quality or current carrying capacity. That is why they are cheap at markets.
There is a 2.5 or 3.0 amp “slow blow” fuse (physical size is M205, ie 20x5mm) in the mains AC power socket, and these fuses are available from Jaycar.
If unobtainable 4.0, and 5.0 amp slow blow fuses will be OK.
There is a soldered in ”disaster” AC fuse in the Danfoss controller, which is intended to be non-repairable by the user.
There is also a 2.5 ohm Polyswitch, with auto-reset, in the controller.
This Polyswitch may have a different value in earlier models.
These items are for fire protection etc.
The metalwork of the CF80 is earthed, including the case, and you should always use an earthed mains lead. Ensure that you restore the case earth connection if you remove it with general repairs.
Be aware that the Danfoss controller is not earthed.
Physical Aspects of the CF80 Case
Most people will be able to service latches and hinges, which are readily available.
I operate my unit without the handles, which are attached by M6 screws.
Latches and hinges are reversible.
The lamp unit is LED and only the switch may require replacement.
This lamp is powered via the “Main Board” from the lamp output on the Danfoss controller.
The lamp voltage is always +12V DC referenced to “C”, and can source 0.5 amp.
The mains and battery input panel is replaceable, but make sure the soldering is perfect.
Compressor Area Cleaning
Brush out debris and dust etc and then blow out.
Blow clean the finned condensor from the fan side.
The fan draws air in from the LHS vent holes and blows out through the RHS.
Replacement fans are available in low noise long life versions, but ensure any replacements have similar airflow specs, and ensure that the flow of direction is outwards ie away from the finned condenser.
I have enhanced the vent panel on my CF80 to have PC “fan protector shields” instead of the normal slotted panel, to give much better flow.
I have an extra separate remote temperature sensor in the freezer compartment, with LCD display unit on my vehicle dash.
These are cheap, and invaluable for monitoring exactly what is going on inside.
Check any thermometers against other devices.
I do not trust the original Waeco type temperature sensor thermistor.
If your CF80 freezer temperature displays -18 C, you may have a problem, as the CF80 compressor is probably permanently ON due to a fault. The Danfoss controller itself is internally thermally protected, and I believe that the compressor can handle long periods of continuous running, eg during “Emergency” operation.
The second main cause of problems with this frig is failure of the thermistor(s) used for temperature monitoring (per display) and control of the compressor.
I suspect the failure mode is with moisture and temperature cycling around the actual thermistor element.
This should not happen and is a design failure of the part itself, not the CF80.
You may not even know about a thermistor failure for a long time, as the CF80 just keeps working, and the freezer temperature is somewhat moderated by the “thermal mass” of the contents.
My thermistor failure showed “ERR1” when my faulty thermistor went open circuit, but I suspect that the thermistor failed slowly and went high resistance over a few months.
If you have a CF80 running normally and then remove the thermistor sensor at Display Board CP5, the Display will show “ERR1”.
There are two thermistor sensors fitted to the CF80.
Supposedly, according to folklore, this is because thermistor replacement by accredited service agents is time consuming, costly and very messy.
The thermistor is a Negative Temperature Coefficient NTC resistor which increases in resistance with falling temperature, the opposite of most materials, which explains the “Negative”.
A Waeco original new thermistor is approx 10K ohms at plus 25 deg C, and increases to approx 50 K ohms at - 11 deg C , then to approx 64K ohms at -14 degrees C.
Caution, these are approx values.
The spare thermistor wired into a CF80 can deteriorate in the same manner as the main thermistor, so both may be faulty after some years.
This happened to my CF80. My faulty “main” measured “open” and my faulty “spare” measured 33K ohms at 25 deg C.
Jaycar 10K NTC, Epoxy coated, Jaycar cat “RN3440” (the actual component device is a TDC310) is sometimes used as a cheap replacement, but it has a different temperature/resistance curve, and is only a rough replacement. The frig may not function correctly and the temperature will display differently to the real temperature. Some have found that wiring a small 100K resistor in parallel with the thermistor gives a better correlation and “almost” correct operation.
You are better to buy an original spare (or two) and install it.
This gives correct temperature readings and correct operation.
If you simply must use the Jaycar NTC, or cannot source a Waeco spare, use a separate and standalone remote thermometer sensor in the freezer, and set the Waeco control board “Temp” to whatever reading gives an actual minus 14 deg.
Experiment with an extra 100K resistor across the thermistor before you seal up the CF80.
On the Top Control Board, the thermistor is connected to connector CP5.
With all CF80 power OFF, and thermistor plug removed, the input resistance of CP5 pin1 to pin 2 is 10K ohms. With thermistor plug connected, and power ON, and with +5V on CP5 pin 2, the DC voltage at pin 1 varies with temperature of the 10 K ohms thermistor, and is approx half the 5V DC supply at 25 deg C room temperature, eg approx 2.5 volts.
Caution with measuring volts at these CP5 pins.
Slipping test leads can destroy a control board, as minimal DC isolation and protection is provided between the Atmega 88V microprocessor chip inputs and outputs and the connector pins.
Test Volts and Indicated Temperature using a Variable Test pseudo “thermistor”
Test volts at Display Panel Board connector CP5 pin 2 to 1 or “C”.
Temperature as indicated on LED display.
Variable thermistor – 100K ohm lin pot.
Caution – approx values, probably differing between various units.
Displayed Temp, Volts, Res K ohm
-18, +4.23, 56
-15, +4.12, 48
-14, +4.10, 46
-10, +3.95, 39
-5, +3.78, 31
0, +3.60, 25
+5, +3.42, 19
+25, +2.5, 10
>+40, 0, 0
Using the Jaycar TDC310 thermistor, at -14 degrees C, CP5pin 1 DC V is 4.0, and the NTC measures approx 46K ohms.
Some physical aspects of thermistor replacement covered later.
There are three circuit boards. The Danfoss controller, the Main Board, and the Display Board.
Waeco call these, in turn, “Electronic Unit” (Danfoss 101N0500), “Main PCB”, “Control PCB”.
Refer to web for Parts List for part numbers.
The Waeco Display Board is sometimes called Top Board.
The CF80 DC power is cabled from the DC Input Socket (soldered) directly to the Danfoss controller via “spade” crimp connectors.
AC Mains is cabled from the Mains socket (fused 2.5A Slow) to the Main Board, through a mains filter on that PCB, and then to the Danfoss controller.
The Danfoss controller has a “rear” facing connection block, which is well labelled, and most of the control and monitoring inputs and outputs are cabled firstly to the Main Board, and then some are cabled up to the top Control Panel.
There are connections from the Main PCB to the “Emergency” switch, and via another connector to the top LED Lamp in the frig compartment.
The temperature sensing thermistor is cabled from the underside of the centre of the freezer section to the top Control Display PCB.
The so-called “spare thermistor” is coiled up and tie cabled to the top roof of the compressor section.
15 Waeco CF80 Interwiring.jpg
Caution – there are different varieties of this board.
This is the PCB which filters the AC mains, and provides a “Mains Available“ signal, (marked “V-test” on the PC board), and also provides connections between the Danfoss Controller and the Top Display Board.
All components on this board are replaceable.
The small connector blocks may be hard to source.
The “V-test” signal is derived from a rectified voltage from the mains “Line” and opto isolated with a PC817 “U5”.
This is sent to connector CP4 pin1 as approx +5 V DC for “mains available” or less than 2.0V DC for “no mains”, ie almost TTL logical “1”=AVBL, logical “0” for NOT AVBL.
This Main Board generates the +5v DC for the Top Control Board using a 7805 voltage regulator U5 and fed to CP4 pin 2.
The regulator U5 takes its +12 V input from the connector marked “COMP” (compressor) pin “A” which is the +12 DC for the frig “Lamp” supply at connector CP1.
It is important to realise that the “Lamp” supply is available if either mains or DC is available, so the Top Display Board always has PCB +5 DC supply, and also the “Mains Available” (V-test) signal is always being generated by the Main Board.
Connector CP3 is connected to the “Emergency Switch” on the CF80 case, and is used to turn the compressor ON permanently and to bypass the thermostat. Resistor R1 (30R) on the Main Board is effectively placed across terminals “T” and “C” of the compressor terminals, and sets the compressor motor speed (approx 2000 RPM) as well as turning the compressor ON.
The Top Display Board can be disconnected and the EMERG function will still work.
The Waeco CF80 will run normally with one or both plugs CP1 (lamp) and CP3 (“Emerg”) disconnected.
The Input Connector for DC and Control is marked on the PCB “COMP” (connected to Compressor).
Output Connector for DC and Control is marked on the PCB “CP4”.
1 +BAT +12 or 24 V DC
2 A (lamp) +12V DC
3 C (common)
4 D (alarm)
5 C (common)
6 P (protection)
7 T (thermostat)
1 V-test (“mains is available”)
2 +5V DC ref to common
3 C (common)
4 +BAT ref to common +12 or +24V DC
5 D (alarm)
6 C (common)
7 T (thermostat)
“Common” is effectively –BAT or battery negative.
The AC filter capacitors and ferrite choke(s) can be bypassed if required by shunt wires from CP8 to CP9 (A to A, L to L), but the connections to the V-test circuit must be maintained.
If the X capacitors fail, they can be left out.
Do not do any of this is you are not competent.
The Danfoss Controller has a built-in AC filter.
This first AC filter on the Main Board has more to do with interference coming out of the CF80 than suppressing anything going into the CF80.
Physical vibrations (or shaking) to the CF80 cables sometimes can cause the PCB connector soldered connections to fail.
Road corrugations can cause this.
If you suspect this, examine all PCB connector pins, and resolder or repair as required. Use a magnifying device as problem joints are sometimes difficult to see.
I have had a Main Board AC failure due to a broken PCB track on CP8, the AC input connector.
It is very, very important that all internal cables in the CF80 are solidly tied down (eg with cable ties etc) to avoid any possible shaking or vibrations.
06 Waeco Main Board .jpg
Display Board (Top Board)
Caution – there are different varieties of this board.
This board has “controls’ and a multi seven segment LED display.
It is microcontroller (CPU) driven by an Atmel Atmega 88V chip, PCB chip U1, with on-board proprietary program.
Later boards used an R5F102AAA CPU for U1.
The SMD CPU chip is cannot be replaced without the specific programming for a CF80 , and so “whole board replacement” is the only option for most “fatal” faults.
Switches are replaceable, caution with “polarity”.
The display chips could be replaced, but in the end, probably it might be cheaper to replace the whole board, especially if your diagnosis of a faulty display is incorrect.
Control signals are input via connector CP4, and thermistor is connected via connector CP5.
CP4 signals are as per Main Board CP4, and are marked on the PCB.
The PCB has a “reset” marked on the PCB, but this is presumably for ATE testing only, and should be left alone.
Both types of CPU chips used on this board are “power up reset” types, so to restart the Display Board, remove and restore the AC or DC power to the whole CF80. Capacitor C7 on the Display Board holds the CPU +5 V up for 2 seconds, so allow for this delay, ie allow 5 seconds between OFF then ON, irrespective of what the LEDs and display read.
Caution measuring voltages and signals on this board, as the CPU has minimal input protection on its pins, and is easily damaged by slipping probes and test leads.
If you have the Display Board out for any reason, check the connector pin soldered joints for integrity.
Resolder if in doubt.
Caution with the connectors on this board as they are small and finicky to remove and replace.
For the techos, here is the test info for Display Panel tactile switches to the microcontroller.
SW1 ON/OFF goes to pin 13, when operated, goes from +5V to 0V via 2K2.
SW2 SET goes to pin 12, when operated, goes from +5V to 0V via 2K2.
SW3 UP goes to pin 15, when operated, goes from +5V to 0V via 2K2.
SW4 DN goes to pin 14, when operated, goes from +5V to 0V via 2K2.
The Display Board draws approx 40mA from the +5V DC input supply.
The +12V DC input to this board is for battery voltage sense, not for power (I think!)
Photos of old and new style Display Boards.
07 Waeco CF80 Display board.jpg08 Waeco CF80 Display board new style.jpg
How the Display Board operates the thermostat function.
The Danfoss compressor is able to use a mechanical thermostat switch (not in the case of our CF80), or an electrical switch in the case of a Waeco CF80, to connect the “T” (thermostat) terminal to the “C” (common or –BAT).
In the Waeco CF80, the Display Board microcontroller U1 (CPU) senses the freezer temperature via the thermostat input on connector CP5, and electrically “connects” “T” to “C” on the connector on that board, and this connects “T” to “C” on the Danfoss controller, which turns the compressor ON.
When the user set temperature is reached, eg minus 14 deg C, this “T” to “C” connection is switched OFF by the microcontroller, and the compressor stops.
The cycle repeats as needed and as the frig warms up slightly.
The temperature is only sensed in the freezer bottom area.
All the time that the Danfoss compressor is switched ON, whether in normal use ie controlled by the Display Board, or by the EMERG Switch, the compressor itself is internally protected against over temperature by its own controller, and will switch OFF if needed to cool down, then the cycle will repeat.
The CF80 could be made to work with a mechanical thermostat connected to Danfoss controller “T” and “C”, so that the thermostat switch contacts are closed for compressor ON, and open for compressor OFF. The Display and Main boards could be bypassed or removed.
This has not been explored.
Waeco CF80 Disassembly
Take plenty of photos before and as you disassemble the unit, especially with the various connectors, and colour code the plugs with a felt pen etc
The compressor assembly is behind the side vent panel, which is attached with M3 screws.
This vent panel may be replaced at some time with a much more effective panel with improved ventilation.
If the CF80 is “built-in”, this ventilation could be further improved by an external 80mm extraction fan placed somewhere in the CF80 cavity.
The extra fan could be a 12V fan running on say 8V using a 7808 regulator, or a 24V fan running on 12V, all to have it effective but almost silent.
The compressor unit is mounted on a bottom plastic plate tray, attached to the CF80 metal frame with M4 screws.
It is easier to remove the whole compressor tray with the CF80 on its side, eg placed on two sawhorses.
The compressor tray can be withdrawn quite some distance with some slight bending of compressor tubing.
The compressor can be removed a little from the plastic tray via the attaching fasteners, but there is little point in this for most repairs.
If you remove the connectors from the Danfoss controller, use a pair of bent nose pliers on each terminal and be very careful.
Do not tug on the wires but on the rear of the crimp connectors.
These “spade” connectors are very tight, and very close together.
If you have to re-terminate, use quality connectors and a good correct crimp tool.
Don’t use side cutters as a crimp tool.
If you have to replace the fan, use quality silent types available from Jaycar etc.
03 Waeco CF80 compressor tray.jpg
Danfoss Controller and Compressor
This CF80 unit uses a Danfoss BD50 compressor and Danfoss 1010500 control unit.
An official Danfoss (now SECOP) brochure is available online for installation and operating notes.
It is a very good document with a lot of information.
You need to read it at least twice.
There are many types of this unit, so beware if obtaining a replacement unit.
There are few replaceable parts inside the controller unit, and I cannot obtain an actual full circuit.
You may be able to replace some capacitors if seen to be leaky etc.
PCB repairs may be difficult as the whole board is weather proofed with a semisoft coating.
The compressor itself is sealed and attached to the controller with a three terminal plug.
Caution as it is possible to reconnect the plug incorrectly ie 45 degrees out.
The compressor motor drive supply DC is actually approx 27 V DC (from an internal SMPS inverter), whether 12 or 24 V DC supply is used.
The actual motor drive appears to be three phase variable frequency AC, and about 80-100 Hz. Amazing.
The controller module is removable from the compressor with removal of one screw and a twisting movement to release an attachment tab. Easiest done with the compressor whole tray partially removed from the CF80 case. There are You-tube videos showing this.
It is possible to run the CF80 with Danfoss controller open on the bench and the compressor and motor remaining in the CF80 case.
Suggest making 1.5 m remote connection cables using eg Jaycar PP2020 connector pins, and 2.0 mm2 copper PVC wiring, eg suitable for approx 8 A. Solder the test cable onto the controller PCB pins.
There is an internal soldered-in fuse on the controller PCB, but if it blows, it may be due to an internal calamity which is not repairable.
This is uncharted specialist territory.
04 Waeco CF80 Danfoss controller cabling colour connections.jpg09 Waeco CF80 Danfoss controller 101N0500 PCB.jpg
Danfoss Alarm Codes.
Refer also to Danfoss Service Note.
Display Panel Indicator (and/or test lamp on Danfoss controller terminal “D” and “C”)
1 flash every five seconds – low DC volts (Test with EMERG switch, if runs, there is a battery or cable issue).
3 flashes – compressor motor problem (rest the frig and then turn on).
5 flashes – controller over temperature, probably indicating a motor problem, or the frig needs better overall ventilation.
Replacement of Thermistor
There are a few ways of doing this. Survey the various methods on the web and chose one.
Here’s what I did.
This operation requires the removal of the CF80 plastic bottom tray like section.
First lay the CF80 on its side and remove the compressor whole assembly out say 5cm.
Then carefully turn the whole CF80 upside down, and remove all the M3 screws attaching the plastic bottom to the internal CF80 metal frame, and three hidden in the compressor tray recess.
With a piece of wood and small hammer on the edges of the tray, and working around the whole case, carefully separate the bottom tray from the CF80 foam insulated carcase.
After you do this wipe the mating surfaces with a small amount of lubricant eg lanolin, to assist next time.
Don’t use WD40.
Withdraw the compressor assembly out of the CF80 case so that the bottom tray can be lifted and rotated so as to gain access to the CF80 side foam insulation.
Two persons are better.
The original thermistor(s) is under the centre of the freezer section, and cabled directly down the middle and between the bottom foam and the frig inner plastic liner the bottom foam, into the compressor area.
Cut the foam as per the photo so as to expose the internal white plastic freezer compartment liner tray.
Your foam insulation may be moist or wet.
If you want to dry this out, leave the whole CF80 out in the sun for a day for trial.
I am told that this wet foam syndrome is a severe thermal load on the CF80 (and others), and causes inefficiency. Allow to cool and settle overnight.
Poke a hole through the foam for the thermistor with say a long screwdriver blade or similar (the foam is soft) so that the hole is approx 10cm long and touching the bottom of the freezer tray.
This is important.
The hole diameter must suit the thermistor, but be a close sliding fit and not too large.
Cut a 20mm sided “V” trough in the foam from your existing foam access area, down to the compressor area, and drill a 10mm hole in the plastic casing angled down into the compressor area, to allow for your thermistor cable and connector.
Spray coat your new thermistor element liberally with lanolin as moisture protection.
Insert your new thermistor into its hole, and run the cable in the “V” trough.
No need for thermal goo if the thermistor is very close to the plastic bottom wall.
Using the cut foam pieces, replace where possible and cover with gaffer tape, after cleaning the surfaces with methylated spirits.
Spray any corroding attachment case metal tabs with lanolin etc.
Do not use WD40.
Re-assemble, and rest the frig upright for an hour before any switch on, then test operate it, using an accurate thermometer. Your freezer temperature may be up to two degrees out, so make “user” adjustments when using the CF80.
My photos show three thermistors being placed. One original and two Jaycar “emergency” NTCs.
10 Waeco CF80 Thermistor Replacement Bottom Access.jpg11 Waeco CF80 Thermistor Replacement Access.jpg12 Waeco CF80 Thermistor Replacement x3 Positions.jpg13 Waeco CF80 Thermistor Replacement new cabling.jpg14 Waeco CF80 Thermistor Replacement Taped.jpg
Wiring and Circuit Diagrams
Attached are an overall wiring diagram, and circuit for the Main Board type HT-MOBICOOL-005-P-V07.
Apologies for rough circuits.
Known Faults For This Specific CF80 Type
Suspect DC power connections, use of thin DC cable giving unnecessary voltage drops. Faulty DC cable with intermittent pin contacts.
Faulty thermostat elements.
PCB connector failures due to continuous vibrations from road corrugations etc.
Defective “Polyswitch” in early Danfoss Controller units.
Clogged condenser fins. Not a fault as such, more a condition. Easily remedied.
good luck to you all.
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30th Jan 2019, 11:04 PM #2SENIOR MEMBER
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I'll add some more common faults to this since I have repaired a few Danfoss units over the years, including some Waeco fridges. As I remember more, I'll add to it.
Blowing fuses on DC, controllers with built in AC - there is a transzorb on the controller board that has gone short circuit.
Increased power consumption - seized cooling fan bearings (my Isotherm boat fridge has this problem right now, just been to lazy to remove it to repair it).
Power supply issues - single led flash - polyswitch (replace it with a proper circuit breaker)
240V PSU - Typical faults in the SMPS such as chopper transistors and drive circuitry.
Display panel - Corrosion due to condensation.
31st Jan 2019, 10:03 AM #3
Seems I forgot to add the circuit of the Waeco Main Board.
16 Waeco CF80 Main Board circuit.jpg
And there is a mistake on my Inter-wiring Diagram.
Where the circuit shows a feed from Display Board CP5 to the Thermostat, it should read "Thermistor".
Re comment by Pearo.
Danfoss Controller 101N0500
Photo shows Transzorb in oval, and Polyswitch in square.
Waeco Danfoss Controller 101N0500 Transzorb and Polyswitch.jpg
The Transzorb is across the DC input.
It may go short if 12V DC reverse polarity is applied.
If you are blowing DC fuses because it is shorted, you could just snip it out for trial.
The Transzorb is a special silicon suppressor diode, used I think as much for spike suppression as well as DC polarity protection.
I actually use a DIY filter (2x100 uH and 2x0.1 MF caps, and 2x24V 5W zener diodes) for extra spike and RF suppression in series with my 12V DC feed, to reduce external switching effects on the DC from alternator and solar charger. The zeners also act as extra polarity protection. The DC V drop is 20mV.
I think the Polyswitch is in the AC mains side of the SMPS.
If it blows then there probably was a major calamity.
Check the large electrolytic capacitors and replace as required.
Note the Danfoss special plug to connect to the compressor motor.
If you are curious about the Danfoss Compressor internals, there is a cutaway photo of a BD35 in the following link.
The CF80 BD50 is similar.
Seems the motor is AC star connected three phase.
You may like to search for other interesting posts in various forums by this same author.
15th Mar 2019, 11:47 AM #4
Waeco CF80 - Some more thoughts.
Waeco CF80 Frig Freezer Operating and Fault or Problem Repair Notes
Some more thoughts.
A most interesting Danfoss document with additional details and info than the brief SECOP document.
This shows the BD35 and BD50 in cutaway section, and importantly, has expected current draw for 12 and 24 volts.
The various graphs refer to temperatures for “Static Cooling”, and as I understand it, these are expected temperatures at the “evaporator” output of the compressor tubing, as Danfoss cannot know or control how the unit is to be used in a refrigerator or cooling situation.
Perhaps an expert can enlarge on this please?
For us with a CF80, this is effectively at the refrigerant “inlet” to the freezer wall.
The freezer wall "inlet area" in my CF80 is 10-12 deg cooler than the temperature at the mid air centre of the freezer cavity.
(This is why you should not attach any replacement thermistors to the exterior of the metal evaporator wall - it does not simulate the original thermistor position, and the freezer will be warmer in the centre of the freezer "space", as the compressor will turn off when the freezer is approx -2 deg C instead of -14 deg C).
So if I set my Waeco for -14 deg C freezer temp, and for dual zone use, I use the temperature of -25 deg C in the graphs, and see that the “expected long term average” idle current drawn is 2.69 amps at 2000 rpm and 4.16 amps at 3000 rpm.
The compressor “power” for a CF80 is limited by design to 100 watts, and this is a theoretical 9.5 amps at 12 V, and it seems to use a practical battery current of about 7.5 amps max at 12 V and a compressor speed of 3500 rpm.
My warm CF80 at startup in a 25 deg C environment, and with an external fixed 1000 ohms for “R1” and with the Waeco Top Display Board in circuit, draws 7.4 amps and settles back to about 6 amps.
The speed sense current is about 2 mA and apparently gives a compressor speed of 3500 rpm.
If I set up a variable resistor for “R1” on the Danfoss Controller, then 650 ohms gives a speed sense current of 2 mA, implying that there is approx 350 ohms internal to the Waeco Top Display Board.
With the CF80 all setup as per normal, except for current monitoring of the speed sense current, the CF80 starts at 4 amps total battery current at 12V, with a speed sense current of 4 mA and a speed of 2500 rpm, then after 5 minutes switches itself to 5 amps total battery current, sense current of 3 mA, and a speed of 3000 rpm, and stays at this rate until the CF80 set temperature is reached.
It seems that a Danfoss “minute” is 66 seconds.
CF80 Foam Insulation
This seems to be an economic and practical compromise for all portable refrigerators, but the CF80 is marginal in my opinion.
And the ingress of water so that the insulation becomes moist or water logged is a major problem affecting reliability (thermistor failures) and thermal efficiency.
It is almost impossible to get all the moisture out of the insulation.
I tried to dry out my CF80 bottom foam which was only a little moist in the freezer bottom area. I had my CF80 in the sun for about a total of 8 hours, but only moisture close to the foam surface is removed by this method, even with the sun directly on the foam.
The wheelbarrow assists with sunlight positioning for drying the foam, not for any anticipated future "use" of my frig.
Drying the Foam of a Waeco CF80 DSC06901.jpg
Moisture seems to get into the foam by multiple possible paths.
1 - By condensation of water vapour in air trapped around the inner insulation itself inside the overall outer case.
2 - By condensation on the outer plastic case, then running down into the bottom plastic tub inside the bottom tub lip.
This is worse with “built-in” installations like mine, with little natural ventilation, and with the minimal CF80 insulation, as it means that the outer case is cool, and condensation occurs.
3 - By water during defrosting getting inside the bottom insulation area via the internal bottom seam of the freezer metal sides and the internal plastic bottom “tray”.
You cannot easily fix the first scenario, as it is a result of design and assembly methodology.
You can reduce the second effect by running a quality 50 mm plastic tape around the outside of the bottom seam, so that condensation droplets run over the tape, and not into the bottom tub.
Sealing Tape on Waeco CF80 case bottom DSC06904.jpg
You can stop the defrosting water problem with a tiny (1-2 mm) seal of silicone all around the bottom frig internal plastic “tray” to metal wall junction. This seal can be tiny and virtually unnoticeable. Use two sections of temporary masking tape to avoid a mess and to restrict the sealant to the tiny join only. Clean the join area meticulously first with methylated spirits or similar.
Screwdriver in photo points to the "seam" to seal.
Waeco CF80 inner bottom tray DSC06905.jpgWaeco CF80 inner bottom tray seal join DSC06905.jpg
You need to do these things when your unit is new!!
At one stage I thought about removing all bottom (only) insulation and replacing with a mix of sheet foam overlying some compressible “rock wool” type material. The outer case inside bottom has plastic protrusions which make replacement somewhat harder. The original bottom insulation should only take 30 mins for complete removal.
Use Of Frig Jacket.
I do not own nor use one of these.
I can see that it will assist in overall insulation, but may need periodic ventilation, or they will pose a severe condensation problem later.
One Waeco repair agent to whom I spoke about these things, started to shake his head and swear!
He said that they are great short term, but cause insulation foam problems long term with condensation.
Good luck to you all.
19th Jul 2020, 06:49 AM #5New Members
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19th Jul 2020, 01:36 PM #6
I have replaced my CF80 with a Waeco Dometic CFX75.
I have posted a separate thread about the changeover, as it is not quite as simple as it sounds.
I see that even it has been discontinued in 2020!!!
24th Sep 2020, 04:05 PM #7New Members
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Can anyone tell me what an Err1 code is when powered up after replacing thermistor on CF80?
25th Sep 2020, 10:26 AM #8
9th Nov 2020, 05:21 PM #9
It is still just possible that either the thermistor or associated wiring and connectors might have a problem.
If the frig operates and cools with the "EMERG" (emergency) switch operated, then it is possible that the thermostat resistor or wiring has a problem.
That switch will force the frig to run continuously, and the freezer will probably cool to -22 deg C or so.
Measure the thermistor resistance from the connector on the "Top Board".
Note that a standard CF80 normally has a second and spare thermistor coiled up and stowed over the compressor area.
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