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After brazing the liguid lines and suction lines between a residental condenser and fan coil is it necessary to evacuate the system and what is the easiest way to do it

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  • witt7229 Jun 03, 2010

    its abrand new system

  • witt7229 Jun 03, 2010

    yes thankyou

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Yes it is absolutely necessary to evacuate the system. But before evacuation of the system, a pressure test should be performed with compressed nitrogen to check and verify that there are no leaks within the system.

The only way to properly evacuate a system is with a vacuum pump. Most professionals prefer a dual stage pump that can evacuate quickly and then kicks into a lower gear to complete the process.

A triple evacuation is the best method, whereas the system is pulled down to 500 microns, and then the vacuum is broke with dry nitrogen. This process is repeated 3 times to complete evacuation. Once the system has been pulled below 500 microns for the third time, the system should be left in a vacuum for at least 5 minutes and verify there is no more leaks or moisture in the system. If after 5 minutes, your micron reading has not elevated, then your good to go. If it has, then you need to continue working.

The reason the system needs to be evacuated is to remove all the moisture from the system. Moisture and refrigerant do not mix and elevated moisture levels within a refrigeration system can cause severe damage to all the components including the compressor, expansion valves, filter driers, reversing valves, service valves, etc.etc... These damages could also void the warranty due to improper installation and start-up practices and procedures.


Posted on Jun 03, 2010

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Hi,

Please check the link bellow and go through the article to have an in-depth knowledge about your query…
http://www.firstfives.org/faq/AC/ac_charge.html

http://www.air-conditioner-selection.com/evacuation-air-conditioning-system.html

let us know if you want somethin more else please accept the suggestion.

Thank You for contacting Fixya.com

Posted on Jun 03, 2010

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Ad50uss is not producing water. Fan and compressor is running . Coils are not getting cold, is refrigerant low? Or could it have a leak? How do u check for refrigerant leak and how do u add refrigerant and...


Compressors have 3 or 5 tubes coming out of the can. Probably 3 in this case. The largest is the suction and the smaller one is the hot gas line. The 3rd is crimped and brazed over. The suction line should be cool or cold (no frost or ice) and the small one should be hot. Be careful of fans. Also, that small line is normally hot enough to burn you. If they are the same temperature, its either low or out of refrigerant (Very common), the liquid line could be plugged (Rare), or the compressor is not pumping (also rare). From here on, you need a compound refrigeration gauge and a line tap. An amp probe would be nice but not needed at this point. If you have an amp probe and the compressor is running and not pumping, the amps will be lower than the name plate RLA or FLA by quite a bit. The name plate should tell you what type of refrigerant it takes. 134A is the new standard but it could be different (R12). Knowing the right type is a must. I have seen compound gauges, line taps, and R134A in hardware stores but you can't add any refrgerant on less your sure no air has gotten in. If the pressure in the suction line matches up close to the ambient temperature when the compressor is off, it has refrigerant. With the gauge on the suction line, start the compressor. If the gauge drops into a vacuum of 25 inches or more, the compressor is probably OK but the refrigerant is gone. If the leak is on the suction side, there will be air in the system. The moisture in the air will freeze immediately at the metering device and it wont get cold. If it all leaked out its another whole process to find and repair the leak, evacuate the system and weigh in the proper charge. I hope this helps. There is a whole process for all of this. Let me know if you have the equipment. I'll get you through.

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How to evacuate system after installing air conditioner air handler?


The service valves are closed. Therfore once you solder to the stubs on the valves your gauges will read what is in the line set and evaporator coil. Pressure test to 150 and let sit. If determined your pressures held then evacuate with vacuum pump. You are evacuating the line set and evap coil only because your service valves are closed. THIS IS THE PROPER WAY TO DO THIS. Once evacuated to 500 microns, close manifold and open valves. You will then see your refrigerant charge and determine if more refrigerant is needed. Good Luck !!

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1 Answer

I have got a gree 60000btu under ceiling unit, the suction pipe is icing up back to compressor its running on 360kPa suction and if I top up the refrigerant it does not change


major causes of evap.freezing dirty coil,evap fan motor or capacitor low on freon.moisture in system. first turn off cooling run fan to completely thaw unit. if possible clean coils and blower wheel. any unit running efficiently the evap coil will be at freezing or below. the key is to have enough airflow across the coil to remove the heat and humidity.its very easy to introduce air and moisture into the system. i have seen alot of techs. over the years make the same mistakes over and over again. when hooking up guages they dont purge the lines back; worst case is only to evacuate freon pull a vacume and recharge

May 22, 2012 | Heating & Cooling

1 Answer

Hi, I need to relocate the split air conditioner, but I don't know the first step and next steps. Thank you,


If you are not a service technician you probably won't have the tools you will need to accomplish the move. Here is what it takes, step bye step. 1. Pull the fuses or turn off the electrical breaker in the house. 2. Hook up a gauge manifold to the Condensing unit ports for the liquid and suction lines. 3. Hook up a Refrigerant recovery machine to the manifold. 4. Recover the refrigerant into recovery tanks down to a trace, no vacuum. 5. Disconnect the electrical whip and control wiring from the condenser. 6. Close off the service valves on the liquid and suction lines at the condenser. 7. Slowly unscrew the copper line connections to the condensing unit to relieve any pressure that may exist from Refrigerant boiling out of the oil in the compressor and quickly cap them. 8. Move the unit to your new, firm and level location. 9. Remove the old electrical disconnect and whip and move it to the condenser. 10. Buy a new line set of the proper length or extend the old one with Refrigeration copper and couplings preserving the condenser couplings. 11. Replace the liquid line drier and reconnect the copper lines to the condensing unit. Replace the "O" Rings if needed to insure a good seal. 12. Hook up a vacuum pump to your gauge manifold. 13. Open the isolation valves on the condenser. Depending on the oil type in the system, evacuate to 250 Microns. 13. Charge system with 50 pounds of Nitrogen and a little Refrigerant for a trace test. 14. Watch your gauges for a drop in pressure indicating a leak. 15. Check all fittings and any splices with a good Halogen gas detector. 16. Evacuate the system again to the point of vaporization of the oil in the compressor being careful not to boil it off. 17. Close off all ports on your manifold and install a small drier to your Refrigerant line. 18. Re-install the recovered Refrigerant, running it through the small drier on your manifold. 19. Re-check for leaks. 20. Install the electrical whip on the contacter and the control wires on the contacter coil. 21.Start the AC and check the running amps against the name plate Full Load Amps (FLA) or Regular Load Amps (RLA) and check the Refrigerant charge against the units chart. Either in your owners manual or glued to the electrical access cover.
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Apr 01, 2011 | Heating & Cooling

2 Answers

I have had a repairman look at this refrigerator and he claims there is a slow leak. Can't a new freon line be installed?


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1 Answer

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1 Answer

I have a 99 chevy suburban that won't cool past 60 degrees and when idling is at 70 degrees. I have replaced the a/c compressor, orfice tube,the accumilator,rear expension valve, and fan clutch. My low...


These numbers are a little high depsite the high ambient conditions.Amazingly enough ,automotive low side suction pressure will equal the degrees its putting out at the evaporator coil...for instance,70 psi low side pressure will produce about 70 degrees of cooling. At 300 psi on the high side(which is high) this is about as low as the suction pressure will go....you need it to go lower.I would probably be concerned with the freon level as a slight overcharge could boost these numbers.Poor air flow through the condenser can also create a higher head pressure than desired.If possible,I would evacuate and re-charge the system with the correct amount of 134a refrigerant. Try to get those pressures lower...about 250/50 would be a decent pressure value in this ambient condition.Verify good airflow through the coils and pay close attention to any foreign debris like plastic grocery bags or wrappers covering the coils...Ive even seen these make their way between the small gap between the condenser and radiator so use a light and inspect carefully for this.Air flow through that condenser coil is vital and any deficit there will create high head pressure which obviously causes high suction pressures....good luck

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2 Answers

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This may be a bigger issue than you want to tackle alone, generally speaking the coil will have to be ordered from a dealer, as most wholesalers will not sell to the general public. Further, this will require brazing the new coil in, evacuating the system, installing a dryer and recharging.

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1 Answer

I have a centrex split systum and it keeps reading e4 can anyone help


E4 = Compressor Overload: this code means that one of the safety overloads on the compressor has activated.

Diagnosis: the compressor has both an electrical and a temperature overload device built into it. The thermal overload will trip if the internal temperature reaches 154.4° Fahrenheit. This error can be reset by turning the unit off and allowing cool down before turning back on.

Causes

Blockage in the refrigerant circle,
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If a blockage is diagnosed, the system must be evacuated, blown back and cleared.
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Compressor problem, if the compressor has developed internal faults, it could simply be starving for oil.
Any other internal problem with the compressor will mean replacement is necessary.

Compressor wiring, if the compressor and/or its capacitor have been wired incorrectly, the compressor could overload.
Rewire as necessary.

Please rate this solution.

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1 Answer

Extremely high head and suction pressures


disconnect the blower and turn on the ac.see if the coil frosts evenly.when you had the system open,you should have changed the liquid line drier.

Jul 29, 2008 | Heating & Cooling

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