Help! A/C coolant not filling correctly

[grotflo]

I'm stuck. I just installed an A/C system in my car. Evacuated it without any problems or leaks, held a vacuum for a half hour to test. I'm trying to charge it with cans of r12a, but something's not right. I jumped the trinary switch so that the compressor comes on when the blower is on. The compressor clutch is working fine. When I fill the low side with coolant, it goes to about 40psi. I turn on the blower and compressor, but nothing happens. The low side is still at 40psi and the high side is still under a slight vacuum. Any ideas what is happening?

The compressor is a Sanden clone, filled with the proper amount of ester oil. Everything brand new, no leaks that I could find. 

 

 

Edited April 16, 2017 by grotflo

[Stevenc22]

Likely a bad gauge or bad connection. Not likely to have no pressure on the high side. Try open the tap on the high side alittle, see if any pressure escapes.

[ray_]

The gauge valve is open, right?

 

[Vicleonardo1]

Not too off topic I hope..

 

Some hydrocarbon based R12a refrigerants (like Red Tek) do not need to be highly pressurized. Low side pressure gauge should read 32-38 psi. If it is installed  at higher pressure it becomes much less effective and and may damage your compressor.(if greater than 60 psi-on the low side) 

 

Also the vacuum pressure at startup needs to be zero, not negative before adding the R12a . It can only be installed on the low side service port. 

 

Cheers! 

[grotflo]

Well, turns out the manifold gauge set I borrowed from Autozone isn't working as it should. I was able to hook up the can of refrigerant directly to the low side port and fill it that way. And that's good to know about the lower pressure needed for Red Tek. Thanks for the replies everyone. 

[grotflo]

One quick question about the negative pressure before filling. So after I pull a vacuum to remove any moisture, should I let air back into the system to get to zero pressure, then fill it up? Does r12a differ from r134 in that regard?

[zinz]

R12 works well when the sight glass has a few bubbles... Helpful in keeping from over pressuring the system, as well. 

[TobyB]

Quote

, should I let air back into the system

NOOOOOOOOOooooooooooooo!!!!

 

The whole pont of a real vacuum (like microns, not mm hg)

is to keep oxygen and h2o contamination to a minimum....

 

t

[grotflo]

That's what I thought Toby. Maybe I misread Vicleonardo1's last paragraph...

[ray_]

4 hours ago, grotflo said:

That's what I thought Toby. Maybe I misread Vicleonardo1's last paragraph...

 

Yeah. What toby said. I'd be interested to see where Vicleonardo got his info...

 

 

Cheers,

[Vicleonardo1]

21 minutes ago, ray_ said:

 

Yeah. What toby said. I'd be interested to see where Vicleonardo got his info...

 

 

Cheers,

 

 

From RED TEK: http://redtek.com/English/product.asp?ID=50

 

R12a aerosol can: Bold is their emphasis not mine: 

 

A) PRE-CHARGE INSTALLATION
1)	Start the engine. Inspect the system and determine if the system is operating correctly. Any repairs should be carried out prior to recharging the A/C system.
2)	Check the system for refrigerant leaks using appropriate leak detection procedures and tools (stock # 606).
3)	Minor leaks from O-ring shrinkage and/or hardening can be repaired instantly by installing RED TEK® LeakStop™ A/C Seal Repair (stock # 401). Leaks in metal lines, condensers, evaporators, fittings, and rubber hoses can be repaired effectively by installing RED TEK® ProSeal™ Advanced Seal Treatment (stock# 402).
4)	Use a duct thermometer (stock# 605) to capture and record the center vent temperature. This will supply the installer a temperature reference, allowing the installer to compare before and after passenger compartment temperature readings.
5)	Determine the type of refrigerant currently in the a/c system. The OEM tag is located inside the engine compartment. The OEM tag indicates the type and amount of refrigerant in the system. If missing, contact the OEM for further information. This must be determined before initiating a RED TEK® 12a recharge.
6)	Evacuation of the refrigerant in the system is recommended prior to installing RED TEK® 12a refrigerant. Recover all existing refrigerants into a suitable approved container and mark appropriately, as FEDERAL REGULATIONS PROHIBIT THE VENTING OF REFRIGERANTS INTO THE ATMOSPHERE. Although RED TEK® 12a is compatible with most existing refrigerants and oils, DO NOT MIX REFRIGERANTS. Mixing refrigerants is illegal in Canada and the US and will not offer the maximum performance available from RED TEK® 12a.
7)	Locate low and high side service ports of the A/C system. Generally, the low side service port is covered by a blue dust cap. The high side service port is usually covered by a red dust cap. All current R134a systems are compatible with RED TEK® 134a Installation Kit (stock# 502).
	Note: R-12 A/C systems will require a RED TEK® Low Side Conversion Fitting (stock# 503) and High Side Conversion Fitting (stock# 504 or 505 or 506) which can be purchased separately.
8)	Determine the correct amount of RED TEK® 12 a Refrigerant required in the system with the use of the OEM refrigerant information and the RED TEK® 12a Conversion Chart.
9)	RED TEK® 12a Refrigerant is installed through the LOW SIDE SERVICE PORT AND IS CHARGED AS A LIQUID INTO A "0" ATMOSPHERIC CONDITION. DO NOT INSTALL INTO A SYSTEM WHERE A HARD VACUUM EXISTS. DANGER!! DO NOT INSTALL ON HIGH SIDE SERVICE PORT.

 

AEROSOL CHARGING PROCEDURE
Follow all RED TEK® 12a safety precautions before initiating charging process.
1)	Before installing can taper (stock# 508) or Installation Kit (stock# 502) make sure valve is fully turned counter clockwise. Thread the can tap assembly on to the RED TEK® 12a can (stock# 301).
2)	Locate Low Side Service Port and connect hydraulic coupler by pushing onto male service port making sure hydraulic coupler is fully secured.
3)	Start the engine and place the A/C on maximum setting.
4)	Turn can tap valve clockwise into the can piercing the can seal.
5)	Invert the can. (Turn upside down). Make sure can is inverted through entire charging process.
6)	Slowly turn can tap valve counter clockwise allowing refrigerant to flow slowly into system.
7)	Continue with charging process as determined by the RED TEK® 12a conversion chart and adequate cooling is attained. Low pressure gauge should read between 30 and 38 psi. DO NOT OVERCHARGE! EXCEEDING 60 PSI ON LOW SIDE CAN DAMAGE COMPRESSOR!
8)	After RED TEK® 12a charging procedure is completed, turn can tap valve clockwise until valve is fully closed.
9)	Remove hydraulic couplers and charging hoses from low and high side service ports. Do not remove can tap if there is remaining RED TEK®12a inside can. Store unused RED TEK® 12a refrigerant in a well ventilated place away from open flames.
10)	Apply RED TEK® refrigerant identification tags in a highly visible area near charging port.

 

Edited April 17, 2017 by Vicleonardo1

[ray_]

That's pretty interesting. 

 

I see their FAQ says that corrosion from moisture is not an issue with their product.

 

http://www.redtek.com/win_12a_faq.html

 

http://www.redtek.com/win_12a_prod.html

 

Q. Are RED TEK® Refrigerants corrosive to air conditioning systems? [top]
	A. No. RED TEK® Refrigerants are non-corrosive, non-caustic, and do not form acids in combination with system moisture.

 

 

[grotflo]

Well shoot, that's interesting.  It's also interesting that you're supposed to charge R12a as a liquid (i.e. turn the can upside down).  From what I understand, R134a is supposed to be charged as a gas because compressors aren't designed to compress the liquid.

 

Based on these instructions, how does one achieve "0 atmospheric condition" without allowing air and moisture back into the system?

[Stevenc22]

Very interesting, seems specific to their product.

 

However these days i dont see the point of using R12. Not only is it harder and harder to get, you really do need to take proper precautions when venting and depressurizing a system.

 

Replaced the Sanden on my system this weekend and hit 35 degrees on R134a.

 

 

[Stevenc22]

8 minutes ago, grotflo said:

Well shoot, that's interesting.  It's also interesting that you're supposed to charge R12a as a liquid (i.e. turn the can upside down).  From what I understand, R134a is supposed to be charged as a gas because compressors aren't designed to compress the liquid.

 

Based on these instructions, how does one achieve "0 atmospheric condition" without allowing air and moisture back into the system?

 

Would have to let air back in!