Engel Conversion To Digital Thermostat

The Navara Forum

Help Support The Navara Forum:

Old.Tony

Administrator
Joined
Oct 3, 2009
Messages
15,345
Reaction score
11
Location
Mid Coast Region, NSW, Australia
Hey guys! My digital thermostat arrive and as promised, I've fitted it and taken some photos and have put together this how-to on what's needed. It's actually a piece of cake to do!

The only issue I can see is operation under 240V. I'll have to work on that, but it works perfectly on 12V. Will have to figure out what's wrong with the 240V and post the changes later.

Items you'll need:

2 to 3mm steel drill bit and cordless drill
Dremel/similar with metal cutoff wheel and wire brush
Soldering iron + solder
Electrical wire, 10A is more than enough, about 500mm total
Crimping tool plus one blue 6mm circle connector
Philips screwdriver PH2 and PH0 sizes
Electrical tape
Wire cutters, thin needle nose pliers
Small amount of enamel paint

Plus the digital thermostat, of course. I bought this one from eBay, and as you'll see it looks like it was meant to be there!

Okay, on with the required steps, there are 9 in all.
 

Old.Tony

Administrator
Joined
Oct 3, 2009
Messages
15,345
Reaction score
11
Location
Mid Coast Region, NSW, Australia
Step 1 - Get the fridge into a handy location. The tailgate of my ute was perfect.




Step 2 - Remove the 4 screws around the top of the fridge's side where the important stuff is. Watch out for washers, mine had two on the end screws above the handle and none on the narrow sides of the cover.



Step 3 - Check the circuit. Do NOT feed the digital controller's power from the permanent 12V power. As soon as you turn the unit on, it will latch the power and stay on until you remove the 12V plug. Connect the + in of the thermostat to the switched power. Use a soldering iron to pop the last connector (soldered onto the circuit board) out.




Step 4 - Mark out the location of the thermostat, not too close to the switch and look underneath to make sure it's not going to get in the way of the circuit housing.



... continued ...
 

Attachments

Old.Tony

Administrator
Joined
Oct 3, 2009
Messages
15,345
Reaction score
11
Location
Mid Coast Region, NSW, Australia
... continued ...

Step 5 - Cut the opening. I drilled the corners, then used a metal cutting disc on my Dremel to make the cut. My fridge had a steel case - take care not to let the Dremel run away and score anything! You will have to cut notches in the side for the thermostat retaining clips but that's going to be dependent on your thermostat.




Step 6 - Connect the wires. It's simple: disconnect the last pin from the circuit board, connect one wire of a pair to the circuit board and the other to the removed pin. Connect the other end of that cable to the relay connections of the thermostat (on my thermostat, marked S1 and S2). Positive power should be connected to the original switch's output - this lets you turn the fridge off!




Step 7 - I tested the connection with a multimeter, the frame of the Engel is connected to battery-negative, so the existing earth point near the circuit is quite appropriate for a negative battery connection for the thermostat. Make sure you have enough wire to allow easy removal of the control panel in case you need to service it. Crimp the connector on the end, put it under the screw and it's done.




Step 8 - my Engel has a plastic clip over where the refigerant and electrical lines go into the fridge. There's just enough gap for me to lay the wire without it impacting on the lid or the seal. I put some electrical tape to hold it in place. Done. While you have the electrical tape out, seal up the connection to the wire that came off the circuit board.



... continued ...
 

Attachments

Old.Tony

Administrator
Joined
Oct 3, 2009
Messages
15,345
Reaction score
11
Location
Mid Coast Region, NSW, Australia
Step 9 - TEST!! Mine ran perfectly under 12V (which means most of the time). It did seem to not behave as well under 240V - I'll investigate it.



So there you have it - digital control! All you have to do (because the Engel thermostat is still working) is turn the original switch all the way up to freeze and let the digital thermostat do its job.

Easy!
 

Attachments

Old.Tony

Administrator
Joined
Oct 3, 2009
Messages
15,345
Reaction score
11
Location
Mid Coast Region, NSW, Australia
Just to report back on how it's going.

1) It turns off when the fridge is fed 240V. Fine. I have to work on that, but not many of us use 240V while we're away camping anyway. I will get it sorted, because I do use 240V.

2) The thermostat has a "difference" function (if you buy the same one, hold the SET button until the display shows P0 then press SET again, it will show P2 and a number below. Set this to something reasonable - I've set mine to 1.0, so the fridge cools the contents until they reach 1.9C (I have the thermostat set to 2.0C and 1.9C is the next step below). The compressor turns off until the temperature rises to over SET + DIFFERENCE which in my case is 3.1C. Sure enough, as soon as it hits 3.1C the compressor comes back on.

Very happy with it so far, just have to work out the 240V issue.
 

Latest posts

Top