Waeco Failure

Assume you mean the pump not working.
Failure to start, with not other indicators, would suggest no power(or a faulty unit) If you checked the supply at the fuse, have you checked the supply from the thermostat? If your power check was from the 'stat rather than the fuse to the unit, are there any cut-outs on the line which may give cause for lack of power? If your power check was from the fuse, have you tried connecting a 12v supply directly to the unit?
Does the unit require there to be gas present and under pressure for the unit to work? (instructions)
If water cooled does water need to be present?
 
Not likely to be total failure. The motor units are pretty reliable - mine still working after 10 years (at last use!). But the thermostat switch could be the problem. Try a direct power feed to see if pump starts.

I got good advice from Waeco direct when I had problems and sent the unit back for regassing and a new thermostat.

PWG
 
Most likely it is a bad contact. The control box is very smart. It is a microprocessor which generates 3 phases and controls the amount of power by the pulse width to the motor coils.
AT START UP IT DRAWS FOR A FEW MILLISECONDS A HIGH CURRENT AND MEASURES THE VOLTAGE DROP. By this method the charge state of the battery is established, if too low the motor doesn’t start.
Connect the control unit directly to your starting battery and use at least a 4mm cable.
Most likely the motor will start. It is the common failure with the DANFOSS compressor.
 
Which controller do you have? The mobitronic or simple thermostat, reverting to the simplest circuit and shorting the stat may help.However, WHERE did you measure the 13volts? It needs to be on the tags to the left of the compressor and someone else needs to switch it on while you're there.(using an analogue meter may help). As already mentioned, there's a high inrush, and the voltage may be dipping due to a bad contact at an inline fuse or switch. look for signs of overheating (discolouration). Also - does the fan run (or pump if it's water-cooled) and is it up-to-speed? These danfoss pumps run for 25 years (constant cycle) in houses and usually get noisy before they die, so it's almost bound to be an external problem.
 
He installed the WAECO 3 years ago and said its the small unit therefore the compressor is a BD35 with the fancy control box.This box is not comparable to the old junk..It uses half of the power of the older versions. Just let him do what I proposed its the common problem with this unit. Isoterm and the big compressor use the external pump for cooling.....
He wrote that he has the small unit.......
The thermostat can be shorted, but why not look for the most common problem first.....
 
Many thanks for replies.

I have tested the voltage at the main terminals, and as said the voltage is 13+ volts (battery on charge).

The unit is a CN 54 (maybe CU??)

I did take the thermostat off the cooler box wall, it seems to work mechanically, but am unsure what voltages and where they are.

The unit is wired to the battery via a switch on the control panel, and a in line fuse. When the switch off the voltage at the main terminal is zero. Have been unable to test as the unit is switched on (not enough arms, and they are too short!!)

I will ring Waeco and see what they say.
 
The way you measured is meaningless. The Controller initiates basically a very high load on the 12 Volt line for a very short time, and measures the voltage drop during these few milliseconds. You will not be able to do the same with your voltmeter. This compressor will not even start if you use e.g a cable with a length of 4 meters and .75 square (that’s the cable which is used for your lamp in the lounge) directly connected to the fully charged battery.
The reason for, it should prevent to completely discharge the battery. If you don’t believe me read the installation manual. It mentions that a heavy cable should be used.
Please excuse my English I am German and my English is not my mother tongue.
 
The way you measured is meaningless. The Controller initiates basically a very high load on the 12 Volt line for a very short time, and measures the voltage drop during these few milliseconds. You will not be able to do the same with your voltmeter. This compressor will not even start if you use e.g a cable with a length of 4 meters and .75 square (that’s the cable which is used for your lamp in the lounge) directly connected to the fully charged battery.
The reason for, it should prevent to completely discharge the battery. If you don’t believe me read the installation manual. It mentions that a heavy cable should be used.
Please excuse my English I am German and English is not my mother tongue.
 
Frank, I am sure you are right about my measurements with a volt meter.

I can only say that my battery is in good nick, and is well charged. The compressor was last run about three weeks ago. The compressor would not run even when the engine was running.

So something has changed.



Yes I have read the maual and I believe the low voltage cut out is about 10.7 volts.

I would put money on that the battery does not go that low even for a second or two.
 
You still didnt get it. If you have any bad contact the resistance will increase and you get a voltage drop. In oder to test the batterie the processor applies a large load, but just a few milli seconds. You will always measure full voltage with no load, but as soon as load is applied the voltage will drop.
If it is not an electrical failure you might have lost some of the cooling fluid. The fluid connector if they are too tight, they start leaking the fluid.
In case you have one of the old control unit (the darlington transistors normaly break and no more available) the control unit will be exchanged for the new Micro processor type.
The new unit has an LED which blinks in case of an error. The number of blinks represent the error. You can look it up. PDf is available on the Danfoss site.
 
Hi MJ,

don't know how good your memory is, but can you remember what the problem is as I have the same problem.

Initially the compressor wouldn't start when the boat was on shore power and the voltage was relatively high, but would start soon after when cruising and the voltage drops a bit. Now it won't even start at all, although I can hear a few 'thrumps' from the compressor as if it is trying to start... The compressor fan works OK, just no compressor. The thermostat seems odd as well, asbthe usual click only occurs around the turning off point.

I have a feeling the control unit has packed up, just hope you can get replacements as just started our 3 week holiday! Part number is CU-55.

Appreciate any assistance, and if you know a Thames dealer as we are currently at Cookham.

Thanks!
 
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