Hello, I'm trying to bypass the original thermostat on my waeco CRX140lt 12v/240v compressor fridge with a digital thermostat and wondering if anyone has done the same and can provide some assistance in identifying the various coloured wires coming out of the block adjacent to the compressor.
I managed to wire up and operate the digital thermostat on the test bench using a 12v lamp but now need to connect to the fridge itself and unsure which wires are which?. Thanks in advance
DeBe said
10:30 AM Nov 29, 2017
Can you post a picture of the compressor controller on your fridge & one of the thermostat you are using.
ROAD RUNNER said
09:05 PM Nov 29, 2017
Hi, haven't sent pictures before so hope they show up. The digital thermostat is the one on the LHS reading 33c
You will need to remove the bottom white wire T , as this is where one of the thermostat wires goes to. The other thermostat wire goes to C but leave the grey wire connected to it. You will meed a 650 ohm resistor in the circuit so the compressor runs at 3000RPM this is the value for a BD50 compressor. Power for the thermostat will come from A+ & C-- , this is 12V dc that feeds the internal lighting in the fridge.
-- Edited by DeBe on Wednesday 29th of November 2017 09:40:10 PM
-- Edited by DeBe on Wednesday 29th of November 2017 09:43:11 PM
The 1.5K resistor was for a BD35 compressor. Interested to know why you want to change to an electronic thermostat? A good clear picture of the circuit diagram on the back of the fridge would be usefull to.
-- Edited by DeBe on Wednesday 29th of November 2017 09:52:21 PM
Peter_n_Margaret said
07:52 AM Nov 30, 2017
BD35 manuals can be downloaded.
Running one at 3000rpm will provide maximum cooling, but will also be least efficient. If the insulation is reasonable it will use less total power if you run the compressor at a slower speed.
Longer cycles at lower speed are more efficient.
Cheers,
Peter
DeBe said
09:07 AM Nov 30, 2017
Waeco upright fridges need every bit of cooling compared to the portable ones. Also his fridge has a BD50F compressor in it. My 80L upright has a BD35F in it.
ROAD RUNNER said
09:09 PM Nov 30, 2017
Thanks D.L. and Peter for your great advice and detailed wiring help, much appreciated. The reason for going digital is that the standard WAECO thermostat appears to work well in summer however becomes quite "lazy" in the winter and the temperature can rise to around 8c or more before the compressor comes on so I think the gap between on and off is far too wide.
A friend of mine with the same model fridge had a "winter" kit installed by the WAECO dealer in Adelaide which alleviated the problem to a degree but the cost was far in excess of an ebay digital controller for around $20, plus I can see at a glance what the temp is.
Thanks again for your valuable advice. Eddy
Hello, I'm trying to bypass the original thermostat on my waeco CRX140lt 12v/240v compressor fridge with a digital thermostat and wondering if anyone has done the same and can provide some assistance in identifying the various coloured wires coming out of the block adjacent to the compressor.
I managed to wire up and operate the digital thermostat on the test bench using a 12v lamp but now need to connect to the fridge itself and unsure which wires are which?. Thanks in advance
Hi, haven't sent pictures before so hope they show up. The digital thermostat is the one on the LHS reading 33c
You will need to remove the bottom white wire T , as this is where one of the thermostat wires goes to. The other thermostat wire goes to C but leave the grey wire connected to it. You will meed a 650 ohm resistor in the circuit so the compressor runs at 3000RPM this is the value for a BD50 compressor. Power for the thermostat will come from A+ & C-- , this is 12V dc that feeds the internal lighting in the fridge.
-- Edited by DeBe on Wednesday 29th of November 2017 09:40:10 PM
-- Edited by DeBe on Wednesday 29th of November 2017 09:43:11 PM
The 1.5K resistor was for a BD35 compressor. Interested to know why you want to change to an electronic thermostat? A good clear picture of the circuit diagram on the back of the fridge would be usefull to.
-- Edited by DeBe on Wednesday 29th of November 2017 09:52:21 PM
Running one at 3000rpm will provide maximum cooling, but will also be least efficient. If the insulation is reasonable it will use less total power if you run the compressor at a slower speed.
Longer cycles at lower speed are more efficient.
Cheers,
Peter
A friend of mine with the same model fridge had a "winter" kit installed by the WAECO dealer in Adelaide which alleviated the problem to a degree but the cost was far in excess of an ebay digital controller for around $20, plus I can see at a glance what the temp is.
Thanks again for your valuable advice. Eddy