Few A/C questions.

[lubbockguy1979]

I would have it either on a thermostat or psi switch for fan activation. On much larger refrigeration and hvac they use either a headmaster or fan cycling to keep the pressures in line for optimal performance. On the hiway and in low ambient temps the fan likely isnt needed.

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[meir]

Ok. so i finished putting all the parts together over the weekend, minus the wiring for the fan that i still did not decide how to go about.
i had a master kit from my other cars, but i could not find an o-ring that will fit the compressor.
in fact, the o-ring i have fits the groove but it dont seem to make contact with the hoses surface once tightened.
so i ordered a kit from LMC Trucks, and guess what? the kit that i got has the same rubber o-rings i had.
this is the compressor i have on the truck:

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i found a youtube video that shows a similar compressor, and the o-rings looks different, so i went to the part store and grabbed a kit for the later models. basically the kit consists from two types of o-rings. green rubber, and a metal one (aluminium?)
here is a pic:

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im positive that the compressor is not the one that came with the truck, as there is a connector that doesn't fit. i think it's the pressure switch?
two pins on the compressor side:

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and only one pin on the connector:

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with the "metal" style o-ring, the compressor lines don't seat flush with the compressor body. is that the way it should be?

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i'm pulling vacuum as i'm typing this comment, so i will update later how it went, but i will appreciate if someone can comment about the o-rings i need to use on the compressor.
also about the blue connector, is that the switch i can use to trigger the fan?

thanks in advance.

 

[studigggs]

The blue pressure switch on the back of the compressor controls the fresh/recirc air door in your cabin. If you dont connect it ,the truck will never call for recirc/max when the high pressure rises. You can cut the single pin female connector off and install a two pin. Just splice onto the existing wire, then run the other wire from the connector to a ground. 2 pin connector part is FOUR SEASONS 37222 Harness Connector.

On second thought, since you are not using 134a, you probably want to ground the existing pigtail. When grounded, recirc will be enabled after 30s of AC operation when the fan is on high or medium speed. If you ever want fresh air, just move the temp selector one notch toward hot and the fresh air door will open.

 

[meir]

The blue pressure switch on the back of the compressor controls the fresh/recirc air door in your cabin. If you dont connect it ,the truck will never call for recirc/max when the high pressure rises. You can cut the single pin female connector off and install a two pin. Just splice onto the existing wire, then run the other wire from the connector to a ground. 2 pin connector part is FOUR SEASONS 37222 Harness Connector.

On second thought, since you are not using 134a, you probably want to ground the existing pigtail. When grounded, recirc will be enabled after 30s of AC operation when the fan is on high or medium speed. If you ever want fresh air, just move the temp selector one notch toward hot and the fresh air door will open.

Wow. That is some good info. I had no clue it works like that.
Thanks.

 

[meir]

So to the update.
I left the metal o-rings in place, pulled vacuum for about an hour, and let it seat for half hour.
Vacuum stood steady on -30, so I started with adding 4oz of oil, and then the Freon. I stopped at 6oz (2 cans) as the gauge showed 38 on the low, and 200 psi on the high. Ambient temp was about 88F.
The Redtek conversion chart shows that I need another oz, but i think 200 psi is a bit high. I’ll have to give them a call on Thursday and better understand their charts.
As of now, the AC blows cold. More then what I will probably use, but Let’s see if it will stand the test of time.
I wanted to measure the temperature when I got home, but my HF thermometer crapped out (I left the batteries inside and that’s not a good idea with the Florida humidity) so I will go get a new one tomorrow and take some measurements.
I’ll keep you guys posted.

 

[lubbockguy1979]

Pt chart in the 200psi range to show the temprature for subcooling and such

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[meir]

I would have it either on a thermostat or psi switch for fan activation. On much larger refrigeration and hvac they use either a headmaster or fan cycling to keep the pressures in line for optimal performance. On the hiway and in low ambient temps the fan likely isnt needed.

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are you suggesting to install something like this?
https://www.amazon.com/Derale-16759...rd_wg=TQRjN&psc=1&refRID=0GNH5M3KFQWXNDDXDZEC

 

[meir]

Pt chart in the 200psi range to show the temprature for subcooling and such

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thanks. i found some charts in the service manual, and on the redtek website. i'll post it later.,

 

[lubbockguy1979]

The page loads to amazon but says its a invalid link

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[meir]

strange. it works for me.
anyway, here is a screenshot.

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not to say that this is the one i will get, just want to know if that is what i need, and if so, what temp range should i aim for.
BTW, i drove the truck again today. AC is great, but i do feel difference at idle.
thermometer will be here tomorrow night, so i hope to take some measurements on the way home.