Just a little note first, below I was working with a mains-powered device, with potential(sic) dangerous results - if you don't understand EXACTLY what you are doing, please, please don't try anything below, if you do know what you are doing, it's easy!
So...our aircon would work well for about 7 mins, then the cool air would slowly become less cold, then it would blow warm air!
After a little investigation, it turned out that the fan for the under-seat unit was not working so it couldn't get rid of it's heat, then the compressor overheat/overload would trip.
This is what I found out:
The fan has 2 speeds, and is automatic, low speed runs at startup (with the power for the fan running through a 220 Ohm, 20 watt resistor) and when the temperature in the fan output area gets too warm, a thermostat bypasses the resistor, and the fan runs faster to be able to remove more heat.
What had happened:
The weight of the resistor (which was supported only by it's wire "tails") combined with driving vibration had caused one of the stiff wires to snap off, right at it's base, thus no power to the fan!
What it should look like:
What mine looked like:
So I went down to jaycar electronics, but the highest rating resistors they had were 10 watt, so I needed to wire 2 x 470 Ohm, 10 Watt ones in parallel, to give me the equivelant (ish - 235 Ohm) at 20 watts.
Once I'd wired them together, i put them back where the original one was, but this time I mounted it with a small amount of silicone (Don't use anything else as it probably won't handle the heat they produce
so now no vibrating resistor and a working aircon!!!
Now:
Cover back on and all is as good as new!
So...our aircon would work well for about 7 mins, then the cool air would slowly become less cold, then it would blow warm air!
After a little investigation, it turned out that the fan for the under-seat unit was not working so it couldn't get rid of it's heat, then the compressor overheat/overload would trip.
This is what I found out:
The fan has 2 speeds, and is automatic, low speed runs at startup (with the power for the fan running through a 220 Ohm, 20 watt resistor) and when the temperature in the fan output area gets too warm, a thermostat bypasses the resistor, and the fan runs faster to be able to remove more heat.
What had happened:
The weight of the resistor (which was supported only by it's wire "tails") combined with driving vibration had caused one of the stiff wires to snap off, right at it's base, thus no power to the fan!
What it should look like:
What mine looked like:
So I went down to jaycar electronics, but the highest rating resistors they had were 10 watt, so I needed to wire 2 x 470 Ohm, 10 Watt ones in parallel, to give me the equivelant (ish - 235 Ohm) at 20 watts.
Once I'd wired them together, i put them back where the original one was, but this time I mounted it with a small amount of silicone (Don't use anything else as it probably won't handle the heat they produce
so now no vibrating resistor and a working aircon!!!
Now:
Cover back on and all is as good as new!
