Waeco ColdMachine constantly running

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livefats

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Our new-to-us Bavaria 30 has a Waeco Coldmachine CU-84 - our first ever boat with a fridge! However, it's struggling to get the temperature down to 10 degrees centigrade (in ambient temperatures of around 17-20.) The fan runs constantly too - no cut off at all, which I presume can't be right.

Any ideas? Googling suggests that the most common problem is icing up - I almost feel jealous about this!

BTW, I've cleaned the unit to get rid of dust, etc.

Thanks for any suggestions!
 
What's the airflow like around the machine? We had problems with constant running until we installed a computer fan next to the vent to extract the warm air. We also created more room around the heat exchanger at the top of the fridge.
 
Check where the thermostat probe is situated. We had the same compressor but with an "accumulator" evaporator plate. Had exactly the same problem and was at my wits end when in desperation I moved the probe from the side / outside of the evaporator to the front / inside, I just tucked it inside the plastic moulding. Completely solved the problem, went from running constantly to just 20 mins in the hour.
 
What Stork said ^^^

Ours leaked from the two brass coupling nuts connecting the compressor to the evaporator plate. Try tightening them. Imperial sizes. The engineer recommended checking the tightness once a year as there's a fair bit of vibration. I have a black marker pen line across both flats as a reference point.

Once you've done that, start the fridge. Take off the cover with the fan in it. The evaporator plate should be frosted all over. Ours was only frosted in the top right hand corner as there was insufficient gas in the system.

We were getting 8 degrees in the fridge with 25 ambient but the fridge was on 50 minutes out of 60.

After a re-gas we are getting 8 degrees on the warmest setting (0) and the compressor only runs for 3 minutes every 40.

Setting it to 7 we got down to negative figures in the bottom. Too cold.

Your comment re the fan running is just symptomatic of the fridge trying to get down in temperature, not a fault.

I have been advised not to go down the Halfords self-recharge route mentioned on here and have yet to read of a successful outcome.

Good luck.
 
Low refrigerant most likely cause and the one I'd address first. Certainly I'd not try and do it myself but get a refrigeration engineer in to do the job.
Over-icing usually results in the fridge working intermittently - I de-ice mine every month (of use, as I live 6/12 on the boat) - and not getting down to temperature. On battery mine (ASU-Isotherm, but exactly the same compressor as Waeco) runs 4/50' and draws 5.5 amps on start-up and 4.0 amps on normal power in 33C ambient.

PS Overfilling with refrigerant gives exactly the same symptoms as you report but is so unlikely that I'd discount it. However, any competent refrigeration engineer will find that out in the 1st few minutes of his servicing.

PPS One problem in UK is that there are few refrigeration engineers who are prepared to visit domestic units (they're quite busy enough with commercial work). I found that taking the unit to their HQ was the only way (and FOC) to get it done. I've just had to re-gas a cheap SMEG unit from JLP and "borrowed", the gear to do it. On the other hand a 38-year old, Freon 12, Neff unit only needed to have the shorting defrost heater disconnected, to start up immediately.
 
Last edited:
Thanks, guys. Lazy Kipper, the airflow seems fine - I've cleared up any dust around the unit and kept the cupboard door open with no result. Hadenough: for the life of me I can't find a thermostat probe - would it be sealed in the cold-box unit? Bav34/Stork - no frosting at all, so I guess it's a regassing opportunity. Charles_Reed - I hope that I'm able to find an engineer in Scotland! BTW, newbie question - how would I measure how many amps it's drawing? (I have a multimeter but not necessarily the understanding to use it effectively!)

Again, thanks for all your input.
 
livefats said:
Thanks, guys. Lazy Kipper, the airflow seems fine - I've cleared up any dust around the unit and kept the cupboard door open with no result. Hadenough: for the life of me I can't find a thermostat probe - would it be sealed in the cold-box unit? Bav34/Stork - no frosting at all, so I guess it's a regassing opportunity. Charles_Reed - I hope that I'm able to find an engineer in Scotland! BTW, newbie question - how would I measure how many amps it's drawing? (I have a multimeter but not necessarily the understanding to use it effectively!)

Again, thanks for all your input.
Click to expand...

we had the same symptoms a few weeks ago, i had already added the computer fan. a re gassing sorted our ancient weaco, its now 5 mins on 20 off
 
Hadenough: for the life of me I can't find a thermostat probe - would it be sealed in the cold-box unit?

May well be. Mine was fixed to the outside but I had one of the gell filled accumulator evaporators (waste of time!). Looking more and more like a re-gas!
 
As an aside, I'm amazed at the heat being pushed out by the computer fan, if it wasn't for the noise I'd add another. It's a quiet fan but wish there were near silent ones.
 
The most likely fault is lost gas due to leakage from the quick couplings. I usually remove these and braze the pipes instead if I install a new system as I get far too many call backs if they are in and through no fault of my own. The other common place for leaks is an aluminium roll bond place gets corroded around where it passes through to the outside of the cabinet or if the fridge is left wet and closed when the boat is not used any part inside the cabinet can rot away. NOTE : It is in my view essential to empty and dry a fridge when not in use and leave the door open to ventilate it. It will not be a thermostat problem if it is running constantly and not reaching temperature it just means the thermostat is working correctly! If you use a refrigeration engineer ask him to remove the gas and cut out the quick couplings and then evacuate the system and re gas it. this should mean many years of use without any need to top up. If there are no leaks it should never need topping up.
 
owen-cox said:
The most likely fault is lost gas due to leakage from the quick couplings...
Click to expand...

It is possible for a system to have too much gas? When I first installed my new fridge I got a load of ice on the very long pipe leading to the compressor, this was with the fridge open, so it was working flat-out. I put some lagging on the pipe, apart from the last 30cm.

Pity the fridge can't make ice inside.
 
livefats said:
Our new-to-us Bavaria 30 has a Waeco Coldmachine CU-84 - our first ever boat with a fridge! However, it's struggling to get the temperature down to 10 degrees centigrade (in ambient temperatures of around 17-20.) The fan runs constantly too - no cut off at all, which I presume can't be right.

Any ideas? Googling suggests that the most common problem is icing up - I almost feel jealous about this!

BTW, I've cleaned the unit to get rid of dust, etc.

Thanks for any suggestions!
Click to expand...

Is the compressor starting and then immediately stopping and then starting again some seconds later? (The fan may continue to run continously)

That is my problem when running off batteries. This is because the control unit detects a low voltage on the supply as the compressor starts. It then stops the compressor to protect the batteries, and the voltage then goes back up again to an acceptable level.

Either the wiring to the fridge is not good, or the circuit for measuring the battery voltage in the control unit is out of wack.
Or may be the compressor is too "stiff"????
 
livefats said:
BTW, newbie question - how would I measure how many amps it's drawing? (I have a multimeter but not necessarily the understanding to use it effectively!)
Click to expand...

Most multi-meters that can read current have three sockets for the test leads: common (or -), + for volts, ohms and maybe low current, + for current, usually max 10A. You need to use the latter and put the meter in series with the load: disconnecting a terminal, say, and placing one probe on each connector. Having finished testing it is extremely important to put the + lead back in its normal socket. Not doing so and attempting to measure volts will fry the meter and possibly cause other damage: this is a surprisingly common error.

A better solution is to get a clamp meter which can measure DC current by placing the jaws round a current carrying wire (single core, not multiple core cable). This avoids the need to disconnect anything and they will usually measure much higher currents. My reasonably cheap one will measure up to 400A so would do even for starting motor current. If considering this option, read the spec carefully: some clamp meters can only read AC current.
 
charles_reed said:
Low refrigerant most likely cause and the one I'd address first. Certainly I'd not try and do it myself but get a refrigeration engineer in to do the job.
Over-icing usually results in the fridge working intermittently - I de-ice mine every month (of use, as I live 6/12 on the boat) - and not getting down to temperature. On battery mine (ASU-Isotherm, but exactly the same compressor as Waeco) runs 4/50' and draws 5.5 amps on start-up and 4.0 amps on normal power in 33C ambient.

PS Overfilling with refrigerant gives exactly the same symptoms as you report but is so unlikely that I'd discount it. However, any competent refrigeration engineer will find that out in the 1st few minutes of his servicing.

PPS One problem in UK is that there are few refrigeration engineers who are prepared to visit domestic units (they're quite busy enough with commercial work). I found that taking the unit to their HQ was the only way (and FOC) to get it done. I've just had to re-gas a cheap SMEG unit from JLP and "borrowed", the gear to do it. On the other hand a 38-year old, Freon 12, Neff unit only needed to have the shorting defrost heater disconnected, to start up immediately.
Click to expand...

For info, I know where there is a bottle of Freon 12, left over from the days of being a restaurant owner
Stu
 
If ice is forming on the pipe to the compressor, it means there is too much gas, making too much liquid, which is not all evaporating in the evaporator. If this liquid gets to the compressor it will feck it!
Stu
 
livefats said:
Thanks, guys. Lazy Kipper, the airflow seems fine - I've cleared up any dust around the unit and kept the cupboard door open with no result. Hadenough: for the life of me I can't find a thermostat probe - would it be sealed in the cold-box unit? Bav34/Stork - no frosting at all, so I guess it's a regassing opportunity. Charles_Reed - I hope that I'm able to find an engineer in Scotland! BTW, newbie question - how would I measure how many amps it's drawing? (I have a multimeter but not necessarily the understanding to use it effectively!)

Again, thanks for all your input.
Click to expand...

Prob is, if you have to regas, where has the gas gone? It must be leaking somewhere, so, find the leak and fix first.
Stu
 
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