Saga of the Fridge Part Two

UPDATE 31 January.

I've been working on the fridge on and off, checking the schematic and pictorial diagrams to make sure that I have correctly identified the wires that feed the fans. I'm glad I had a look because the positive is white and the negative is black.

My final idea was that rather than cut and splice into the original wiring I decided to connect the new fans in parallel with the original ones using new wire with spade connectors and a home made Y adaptor for both positive and negative. This way, when (if) I replace the original fans I won't have to deal with wires that had been cut and spliced.

When the fans first failed I had bypassed the thermal switch and found that one fan started. It later turned out that the connections on the switch were a bit tarnished. It is working fine now that I cleaned them up. The red wire is the new + feed for the new fans, connected here to one side of the thermal switch. The black and white wires are original. The short pigtail will connect to the original fan positive, the white. The black wire will connect to the top terminal of the switch.

I eventually tracked down a couple of 120cm fans, bought some wire and crimp connectors. I had some but not all the right ones.  A trip to the glass shop where I had the mirror cut yielded some anodized aluminum channel stock from their scrap bin which they cut down the middle to provide a couple of pieces angle stock. I cut 4 brackets from these and had two one inch pieces left over! Cost for the aluminum and the cutting: 30 pesos. About $2.50 Canadian dollars.

 Using our small folding table and a scrap of lumber from the restaurant and a pair of vice grip pliers I assembled a work bench.

I knew I had a hack saw someplace but even by almost emptying my large bin of tools and stuff I couldn't find it. I ended up cutting by holding the bare blade in my hand. Not the easiest thing to do.

It took much longer than expected to cut and shape the cutouts so the brackets wouldn't reduce the air flow.

Eventually I had 2 brackets cut and one fan mounted to them. The second set went a little quicker but not much.

By now my hands were sore and tired, enough for one day!










Yesterday I had bought a bag of zap straps--I already had some very large white ones which of course weren't long enough and I wanted some a bit thinner so I wouldn't have to drill too big a hole in the brackets. I also picked up a metre and a half of # 14 red/black parallel pair, though I'll only need about a third of the red wire for the positive lead. I'll make that at the thermal switch. The black negative will have to reach from the new fans down to the circuit board. Hope I bought enough!

 Today, Sunday, I paralleled the very thin red and black leads from the fans and crimped on the spade connectors. I then mounted the fans in their brackets into place, having spent quite a bit of time figuring out what would go where. They went in quite well, it took a bit of care to get the straps tight enough without pulling the fans upward. I only had to replace one strap that I had pulled too tight. :)





Once they were in place and secure it only took a few minutes to add the new wires. I had Gillian turn the fridge off  and I got to work:

I started at the top and first I dropped the black wire down to make sure it would reach the circuit board. It did! I plugged the negative ends together (top left corner of the left hand fan--hard to see in the picture) then the new positive lead to the new fans, then the pigtail to the positive wire that connects to one side of the thermal switch, then removed the jumper I had put and reconnected the other terminal from the switch.




Down the ladder to the ground. Now the nervous part. Could I remove the negative wire and plug in my new one without damaging the circuit board connection? Then I realised that I had to reroute both the original wires around a bracket to get enough slack for the pigtail. They came down from the top the up and over a bracket then over to the circuit board. It seemed to be a silly way to route them but a gently pull with a pair of long nose pliers and they came out quite easily and I passed them under the bracket. I connected the old wire to the pigtail and then carefully pressed the spade connector onto the lug. This had to be done by feel as it was almost impossible to see.



Then I had a small brainwave. Take the opportunity to try to clean the gas burner so the igniter would work. We have been running the fridge on the electric heating element because the gas flame had been intermittent and often wouldn't relight.

I "borrowed" one of Gillian's emery boards and gave it a good clean then put the cover back on.

 Now for the moment of truth: Turn the fridge back on. The fans came on! Up the ladder to check everything--the one original fan that had been working now was not. I thought perhaps the thermal switch had indeed failed so I put the jumper back in to no avail. I have left it in anyway.

The fins cooled to about 106F, the food inside the fridge is a very nice 38F, all seem well.

MONDAY; the fins are a bit warmer in the 87f heat of the afternoon, they were at around 110F.  This evening at 6:30 they are at 99, but the food is warmer! I'll have to keep an eye on this for a while.

I may be able to get some better cooling by adding a sheet metal baffle from the outside edge of the fans to the bottom corner of the fins to direct more air through the fins.  There appears to be more space in front of the fins that the specs call for. I'm going to post some of this and a photo or two on the RV.NET forums and see if one of the techs responds.