Hi , i know that switch can be adjusted but just don't remember how .
Do i have to turn it on left or right ? That's the one on the accumulator ( The adjustment is on the switch )
That's on a 88Gt 2.8 Liter 5 speeds .
Thanks

[This message has been edited by Robert 2 (edited 06-25-2011).]

ttt

bump maybe one day somebody's gonna answer .

I just went through the entire section on air conditioning (including all the troubleshooting charts) in the '88 service manual and found nothing related to the pressure cycling switch being adjustable. The service manual says it's supposed to cycle on between 41-51 psi and cycle off at 20-28 psi. The test procedures indicate that if it falls outside these specs, you must replace the switch.

Yeah this is what i did too ( have the 88 manual just sitting in front of me on the kitchen table )
Tommorow , i think you have an 88 ? take the connector off the switch and look , you will see a screw there , that is supposed to be the adjustment . I did it a few years ago but just don"t remember how .
Somebody on here told me how , don't remember who but i'll look a the number you just gave me tommorow . Not sure if that was the owner of an A/C center around my place .
Also how many cycle should i have within a minute to be good .
Thank for your answer .

I changed the switch 20.00$ tax included .

[This message has been edited by Robert 2 (edited 06-11-2011).]

IIRC the switch is adjustable by a screw, accessible when the switch is removed. It's been awhile since i've seen one, so I may be mistaken.

Accessible when you undo the connector .




Yes that is an adjustment , you can read it on the first line on the label but the guy at the A/C place told me not to play with it .
Told me they know how .
As for the cycling he told me that when it is very warm and humid , that the cycling can stay on all the time
As far as the kicking in at 20 and out at 50 ( mine is 40 kicking in and 70 kicking out ) he say that it doesn't matter . Could be that this switch is meant for R-12 and i have R-134A in mine .
But that's what he said , not me .
But i think he knows better than me ( hope )

Also you are supposed to just tight the cycling switch by hand so you'll not crush the little "O" ring , and you don't need to empty the system to change the switch , there is a shrader valve on the accumulater on back of the switch .
If the pressure is going too high the switch or pressure valve on the compressor is supposed to take it in charge .

[This message has been edited by Robert 2 (edited 06-11-2011).]

A comment on what you were told about cycling. The cycling is controlled by the pressure switches. Temperature or humidity have no input on the Fiero AC system. Given the same system pressure, the compressor will cycle just as frequently in the dead of winter as on a hot rainy summer day.

quote Originally posted by fierofool: A comment on what you were told about cycling. The cycling is controlled by the pressure switches. Temperature or humidity have no input on the Fiero AC system. Given the same system pressure, the compressor will cycle just as frequently in the dead of winter as on a hot rainy summer day.

And what is the cycling switch's on for then ? Just asking .
By the way thanks for the answer .

[This message has been edited by Robert 2 (edited 06-11-2011).]

During the cycle, the refrigerant changes back and forth between a liquid and a gaseous state. As the refrigerant changes to a gaseous state, it expands, increasing the system pressure. The AC pump is cycled on as the system pressure drops below a given set point. The compressor runs until the cycle switch senses a given high set point and turns off the compressor clutch so that the AC system doesn't over-pressure and explode. As the pressure drops to the low set point, the compressor clutch is energized again. I have had a cycling switch fail and it blew the overpressure valve out of the back of the compressor.

Just like the cooling fan switch should cycle on at 235 degrees and off at 195 degree to activate the cooling fan. There are no environmental inputs for the Fiero heating or air conditioning system.

[This message has been edited by fierofool (edited 06-11-2011).]

Thanks for the info .

quote Originally posted by fierofool: A comment on what you were told about cycling. The cycling is controlled by the pressure switches. Temperature or humidity have no input on the Fiero AC system. Given the same system pressure, the compressor will cycle just as frequently in the dead of winter as on a hot rainy summer day.

True, but a hot, humid day is going to increase the load on the a/c system, so at high fan settings and without recirculate the system may never trip the cycling switch.

quote Originally posted by masospaghetti: True, but a hot, humid day is going to increase the load on the a/c system, so at high fan settings and without recirculate the system may never trip the cycling switch.

What do you mean by high fan setting ?
The radiator fan , or the control panel for A/C set at "MAX"
On my GT 88 there is only one speed for the radiator fan .
Guess you mean the A/C control panel ?

quote Originally posted by fierofool: Temperature or humidity have no input on the Fiero AC system. Given the same system pressure, the compressor will cycle just as frequently in the dead of winter as on a hot rainy summer day.

That's misleading. Since the AC system operates with the refrigerant at the saturation (i.e.boiling/condensing) point, the operating pressures are directly related to external temperature, and the evaporator pressure is even indirectly affected by ambient humidity. In winter the operating pressures will be lower and the compressor will cycle on much less frequently than on a hot summer day.

Temperature and humidity are an indirect effect through convection. There is no sensor on the Fiero AC/heating system that measures temperature or humidity and inputs that information into the operation or cycling of the compressor. If there was a sensor, it would need to be in the cockpit since that is the area being affected by the climate control system. If such were present, the temperature slider control would cause the compressor to cycle more or less often due to the interior temperature. Yes, the compressor may cycle at a different rate as an indirect effect of outside temperatures, but the cycling is controlled strictly by the pressure set points of the switch.

Bump
For Bloozberry .
Did you find the little screw ?

[This message has been edited by Robert 2 (edited 06-25-2011).]