Year: 1989
Make: Citroen
Model: CX 2500 Turbo
Engine Size: 2.5 ltr
Refrigerant Type: R12a
Ambient Temp: 32
Pressure Low: 30
Pressure High: 95
Country of Origin: Denmark
I have just replaced everything but the Evaporator system is charged and cooling, maybe not quite enough but good results. I have operated the system without wrapping the expansion Valve in the black sticky stuff, as i would like to check for leaks. It did sit for an hour without any drop in vacuum before I proceeded to charge.
I read through a recent thread which dealt with heater and A/C mixing in order to create the proper cabin temp. I think that I might be in the same boat, i.e. that I won't be able to reduce the temp below approx 15 degree C as thats lowest setting. I will try the test you mentioned "how much hotter is the vent temp vs the outside temp" before cutting/bypassing hoses. Good suggestion.
I need to mention that it's a "H" block unit with a short 1" tube, (no external bulb)
1) But what impact does me not having wrapped the expansion valve yet?
2) And Can I wrap the expansion valve in some plastic to prevent the unit from being so unpleasant when removing it again, in case I need to e.g. flush my evaporator, which I didn't do
Thanks in advance
Preben
Edited: Wed July 30, 2008 at 12:05 AM by pridbor
Expansion valve can;t read the superheat of the core correctly without it being wrapped. No way to have proper performance without it wrapped!
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OK But can I wrap it in plastic first without perturbing it's functionallity?
Not in my opinion.
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Anybody know the "name" of the effect of generating cold through high pressure to low pressure?Ttypically the name of the fellow who figured it out
Just curious
Thanks
Preben
You can "google" the history of airconditioning and get many different answers and education, like THIS ONE If I had more time i'd go further, but Googling can really help answer questions like this...Hope this helps...
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Chick
Email: Chick
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Freedoms just another word for nothing left to lose
You must be asking about the "Joule-Thompson effect"
http://en.wikipedia.org/wiki/Joule%E2%80%93Thomson_effect
Other than that, it's just vapor compression refrigeration. There are other types of refrigeration also.
Also,
I believe it's "Prestite Tape" you want to wrap your TXV or thermal bulb or whatever in.
https://www.ackits.com/pc/250-292/Miscellaneous/Prestite+Tape
I wrapped the expansion valve I get some much better numbers than before I replaced the expansion valve, but not quite to my liking.
About 16 degree C at idle, but all the way down to 7-9 degree C when driving 60 miles an hour. The latter is not bad at all.
Going from an idle speed of 1000 to 2500 brought the temperature down from the 16 to about 10 - 11, is there a message in this?
E.g. is the Compressor running too slow at idle? I must mention that the A/C was made as an after thought on this car as it never was conceived with A/c from it's inception. The compressor is driven by the camshaft, running as you all know at 1/2 speed of the engine, so I don't know if the pulleys are bringing the Compressor RPM up to the correct speed
Question: Can anybody please inform me what RPM a compressor is supposed to run at?
Thanks
Preben
Most perform best between 1500 and 3000 RPM.
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