DBK
LIFE MEMBER
There have been a few thread on here about fitting a PC cooling fan to the back of the MH fridge to improve performance in hot weather. Although we haven't suffered from poor cooling in hot weather we also haven't suffered any extreme temperatures either so far but I guess it is only a matter of time before we do so I went ahead this week and fitted a fan to our fridge.
The following describes what I did.
The two main parts are a temperature controller, which although not essential I felt it was a bit more "elegant" a solution to have a controller rather than just switch the fan on and off when I felt we needed it. The other was the fan itself and I went for quite an expensive one as I wanted the fan to be quiet and the one I bought is almost inaudible but you can get much cheaper ones.
The temperature controller was this one, part number SKU107685 bought from here for the massive price of £3.29 with free postage. Broken Link Removed
This came within a couple of days but it was free of any instructions but a bit of Googling found this website which explains what the terminals are and how to use it. Broken Link Removed
The fan I bought was this one: Broken Link Removed
The installation after I had finished looks like this:
Of course in our PVC access to the fridge is very easy as it is behind one of the rear doors.
The temperature controller was fitted inside a modified Raspberry Pi case but you could use more or less anything which holds it in place. As mentioned you can get cheaper ones but this one is very quiet. This fan has three wires, the red is positive 12v, black negative and the yellow is the control wire which is not needed. It comes with a second bit which has a resister in it to make the fan run slower and even more quietly which I modified by cutting off the resister and using what was left as the connection to the temperature controller after pulling out the yellow wire from the plug.
The fan and the Raspberry Pi box were all held in place using cable ties fitted through the plywood shelf the cooker fits on.
In the picture above the leftmost cable tie is holding the temperature sensor. The tie which runs transversely is securing the temperature controller and the bottom of the Raspberry Pi box.
Rather than try and draw a wiring diagram I will explain the wiring using the four terminals on the temperature controller which are marked K1, K0, +12v and GND, which you can see on one of the pictures here; Broken Link Removed
The +12v terminal was connected through an in-line 1 amp fuse I bought from Halfords to a 12 volt supply I took off the back of the cooker where there was a convenient terminal block I could tap into. The GND was connected to the negative wire from the cooker.
The K0 and K1 I initially thought were for the load but they are simply connected to the contacts in the relay and close when the set temperature has been reached. So to get the power to the fan I connected a loop of wire from the GND terminal to K0 and the connected the fan across the +12v and K1 terminals with the red wire going to the +12v terminal of course. This does mean the fan is permanently "live" as the switch is in the return but this was just the way it happened. It would be better to have the switch in the positive feed I think but this can easily done. You might be able to see how it is wired this in the picture below:
The red and black wires coming out at the bottom are the supply to the fan. The little white plug in the top right is the connection to the temperature sensor.
There are three little buttons on the temperature controller. If you press the one marked "set" once the display will flash and you can then use the + and - buttons to set the temperature the fan controller will come on. I set it to 25C at first so I could test everything worked as you can then hold the sensor in your fingers to warm it up and after seeing the fan start up you can let go and when the temperature gets to 23C the fan will switch off.
You could do this for under £10 although I spent a bit more. It isn't a perfect installation as the 12v feed from the cooker is permanently on and is not part of the "Aux" circuit which is controlled from a switch inside the MH but I couldn't find any 12v switched supply anywhere near the fridge other than its own 12 volt supply which only comes on when the engine is running. So at the moment the fan can only be permanently switched off by removing the fuse - which isn't hard but I need to put a switch in there somewhere.
The following describes what I did.
The two main parts are a temperature controller, which although not essential I felt it was a bit more "elegant" a solution to have a controller rather than just switch the fan on and off when I felt we needed it. The other was the fan itself and I went for quite an expensive one as I wanted the fan to be quiet and the one I bought is almost inaudible but you can get much cheaper ones.
The temperature controller was this one, part number SKU107685 bought from here for the massive price of £3.29 with free postage. Broken Link Removed
This came within a couple of days but it was free of any instructions but a bit of Googling found this website which explains what the terminals are and how to use it. Broken Link Removed
The fan I bought was this one: Broken Link Removed
The installation after I had finished looks like this:
Of course in our PVC access to the fridge is very easy as it is behind one of the rear doors.
The temperature controller was fitted inside a modified Raspberry Pi case but you could use more or less anything which holds it in place. As mentioned you can get cheaper ones but this one is very quiet. This fan has three wires, the red is positive 12v, black negative and the yellow is the control wire which is not needed. It comes with a second bit which has a resister in it to make the fan run slower and even more quietly which I modified by cutting off the resister and using what was left as the connection to the temperature controller after pulling out the yellow wire from the plug.
The fan and the Raspberry Pi box were all held in place using cable ties fitted through the plywood shelf the cooker fits on.
In the picture above the leftmost cable tie is holding the temperature sensor. The tie which runs transversely is securing the temperature controller and the bottom of the Raspberry Pi box.
Rather than try and draw a wiring diagram I will explain the wiring using the four terminals on the temperature controller which are marked K1, K0, +12v and GND, which you can see on one of the pictures here; Broken Link Removed
The +12v terminal was connected through an in-line 1 amp fuse I bought from Halfords to a 12 volt supply I took off the back of the cooker where there was a convenient terminal block I could tap into. The GND was connected to the negative wire from the cooker.
The K0 and K1 I initially thought were for the load but they are simply connected to the contacts in the relay and close when the set temperature has been reached. So to get the power to the fan I connected a loop of wire from the GND terminal to K0 and the connected the fan across the +12v and K1 terminals with the red wire going to the +12v terminal of course. This does mean the fan is permanently "live" as the switch is in the return but this was just the way it happened. It would be better to have the switch in the positive feed I think but this can easily done. You might be able to see how it is wired this in the picture below:
The red and black wires coming out at the bottom are the supply to the fan. The little white plug in the top right is the connection to the temperature sensor.
There are three little buttons on the temperature controller. If you press the one marked "set" once the display will flash and you can then use the + and - buttons to set the temperature the fan controller will come on. I set it to 25C at first so I could test everything worked as you can then hold the sensor in your fingers to warm it up and after seeing the fan start up you can let go and when the temperature gets to 23C the fan will switch off.
You could do this for under £10 although I spent a bit more. It isn't a perfect installation as the 12v feed from the cooker is permanently on and is not part of the "Aux" circuit which is controlled from a switch inside the MH but I couldn't find any 12v switched supply anywhere near the fridge other than its own 12 volt supply which only comes on when the engine is running. So at the moment the fan can only be permanently switched off by removing the fuse - which isn't hard but I need to put a switch in there somewhere.
Last edited:
