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Amo

A/C temp control

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I have freon added every year.  It'll be low, but not bad.  I know the 85/88 series isn't known for its cooling ability.  It has worked well years ago.  Just curious if the tempature knob ever goes bad.  I'll go to turn it down in the evening and it never changes.   I just have to turn the blower knob on and off.  Yet during the heat of the day, it barely cuts it and a lot of times it doesn't cut it.  Thinking even though I can turn the knob that something isn't adjusting like it should.  I asked my when he was adding freon and he said no, but I'm not sure he understood my question either.

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I see very few thermostatic switches go bad IT does happen ! But I see a very high percentage of tractors with a dirty evaporator and with the little foam dams along the side missing that with a deteriorated top foam allows air to go around  the high  resistant  of a dirty evaporator

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it is possible that the switch is getting bad and not kicking in/out properly, there is two little adjustment screws on them switches to adjust cut in and cut out temps but you need a thermometer to stick in your vents to know what temps the switch cuts in/out at. like r190 said probably a dirty evaporator core

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I have a piece of foam insulation over the top of everything.  I don't think there's ever been any other "insulation" up there.  Just the foam thing that I replaced with Styrofoam insulation underneath the access panel from the top.

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On a cooler part of he day with  tractor cold, out of the sun, doors and windows closed,  Turn temp control off. Start tractor. Now in very small increments, turn temp control up and watch compressor for  on and off.  Normal would be that at lowest setting, compressor will turn on but shut off soon, little more turning,  comp run for a bit and turn off.  This should work for first part of test but even a good control might not keep turning compressor on and off at higher setting  as system may not be capable of reaching temp needed to turn comp off.  If you can't see compressor turn off and on a test light in the circuit to compressor will show you power on off. 

Also, make darn sure the coolant valves are shut off to heater and evaperator

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Ok here's what I got.  The evaporator is the radiator thing, right?  Yes, the lines are shut off from the radiator

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Radiator is clean

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Am I blind as I am not seeing the sensing tube from the temp control inserted in between the fins on the evaparator from top down, maybe about middle side to side, a row back from front. 

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30 minutes ago, pete23 said:

Am I blind as I am not seeing the sensing tube from the temp control inserted in between the fins on the evaparator from top down, maybe about middle side to side, a row back from front. 

It's on the left edge of the evaporator pic.  There's like a #9 wire looking thing on the left edge of the evaporator pic.  It's stuck down through the fins of the evaporator.

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1 hour ago, Amo said:

It's on the left edge of the evaporator pic.  There's like a #9 wire looking thing on the left edge of the evaporator pic.  It's stuck down through the fins of the evaporator.

OK,  I normally put them more  toward the center front of evaperator behind first coil. 

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I agree with everybody's thoughts------and going one step further:

I had the temp sensing tube broken off from the temp switch (resulting in the temp switch not working on my 2090 Case

I straight wired a simple pull/push switch to get to going over the weekend.

It will tell you if the compressor is working.   Uhhhhhb-------I am still running it by turning the compressor off occassionally.  If the compressor runs continuously--------more than likely the coil will ice over.

Air flow is normally the culprit.

 

Good luck------hot weather is here today in Mississippi.

 

DD

.

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In my experience when its smoking hot mine runs alot. My 1086 is getting weak because on a hot day I can feel it cycle on and off. I just charged the system and pressures are great.

On those dudes. Clean the condenser coils and radiator good with coil cleaner. If the fan cant move air through strike 1. I leave them on recirc or put a piece of cardboard inside your cab filter then stick your filter back in so it has to recirc. Both of my luvers are froze up. Next use coil cleaner on evap up top. Flush them good and blow out your pan drains to keep it from leaking all over in the cab on hills. Make sure its pressures look good on gauges and they should be comfortable. Mine on a super hot day keep you cool. They work hard. My thermostat switches turn about 1/4 turn past where they should and I often wonder if I should run them there or where they should be. It's like a freightliner gas pedal. Theres an indention in the floor board where you give it just another little bit. Lol

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Never thought about the thing being stuck open that let's outside air in vs recirculating

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6 hours ago, Amo said:

Never thought about the thing being stuck open that let's outside air in vs recirculating

Oh yah. Takes 5 minutes to carve out some cardboard then just stuff the filter back in. Easy and nobody knows any better. These old cabs leak enough fresh air it's not a problem. Makes a noticable difference 

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