# Air con making funny noise - should i worry?



## 4ePikanini (Aug 29, 2007)

Just had my AC gassed.
This valve is making a funny noise when i engage the aircon. almost like a pressure release sound. when i listen to it via a stethoscope i cycles on and off. is this normal?


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## 4ePikanini (Aug 29, 2007)

anyone with an opinion?


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## 4ePikanini (Aug 29, 2007)

ttt


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## twinair (May 12, 2008)

*Re: Air con making funny noise - should i worry? (fourie_marius)*

I'm not getting a pic.


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## 4ePikanini (Aug 29, 2007)

http://img300.imageshack.us/im...2.jpg


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## ziddey (Apr 16, 2006)

*Re: Air con making funny noise - should i worry? (fourie_marius)*

maybe try adding a few ounces of oil?


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## 4ePikanini (Aug 29, 2007)

its newly oiled and gassed


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## 4ePikanini (Aug 29, 2007)

aircon pressure gauge on the way. gonna check it cus the ****** guy gassed it by feel. i hate that! i like precision.
anyway will let you guys know when ive hooked up the gauge.


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## twinair (May 12, 2008)

*Re: (fourie_marius)*

If its the TXV making the sound it is normal for it to "hunt" meaning it is consttanly adjusting or metering refrigerant flow through the evaporator coil based on vapor line temperature. Also unless you understand what you're looking at when you're checking pressure there really is no point in checking. At 80 degree outside ambient the vent should put out 45 degree air at medium fan speed. Also if the guy who gassed it didn't evacuate the system first then you need to recover the charge, evacuate, then recharge making sure not to introduce atmosphere into the system. This will also cause the TXV to hunt more noticably and not cool well.


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## 4ePikanini (Aug 29, 2007)

Thanks. It was vacuumed prior to gassing
Is that TXV a mechanical valve cus i dont see any electrics going to it?


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## 4ePikanini (Aug 29, 2007)

*Re: (fourie_marius)*

bump. i also noticed that it the compressor doesnt cycle on and off. should i worry? 
pressure is in spec with accurate gauge.


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## twinair (May 12, 2008)

*Re: (fourie_marius)*

It is mechanical and meters refrigerant based on evaporator outlet temperature.


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## twinair (May 12, 2008)

*Re: (fourie_marius)*

what is the air temperature coming out of register?


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## 4ePikanini (Aug 29, 2007)

dont have a probe but its pretty cold. id guess between 8 and 12 degrees celsius


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## 4ePikanini (Aug 29, 2007)

that makes sense to me then. thanks
it just still doesn't really explain why the compressor is not cycling on and off


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## 4ePikanini (Aug 29, 2007)

ok. so after reading this page
http://www.crtech.com/txvResponse.html
i understand how the thing works and controls flow. does that mean that the TEV is the regulating equipment and that the compressor will always be engaged and pumping?
That seems to be an inefficient way of doing things, don't you think?
OR - is there another valve maybe in the pump itself that only allows the pump to pump up to a certain pressure and the TEV will make it happen that the pump is sometimes just turning but not actually pumping?


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## 4ePikanini (Aug 29, 2007)

ok. i think ive figured it out now.
temp to evaporator is controlled by thermostatic expansion valve that mecahnically measures flow and temp from outlet of evaporator and so controls flow into evaporator. This will help the evaporator to not freeze over.
BUT then we have a problem of excessive build up of pressure before the TEV if the compressor does not cut (which mine doesn't). 
I have now found (through hours of google) that the compressor has a valve that makes the pump a VARIABLE displacement pump. hence that is how it controls pressure no not exceed dangerous levels and TEV controls temp going into the evaporator.
NOW.....I just gotta live with the noise. (i suppose its a affirmation that it is working)
Thanks for all the input and let me know if i missed something or maybe got it all wrong.


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## 4ePikanini (Aug 29, 2007)

its a bit of an inefficient system and i found it strange that i had to figure this by adding lots of small pieces of info on the web. absolutely nowhere could i find this system explained as a whole on the web.


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