Unable to Charge AC System - Team Camaro Tech
Heating & Cooling Heating, cooling and air conditioning

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 21 (permalink) Old Apr 23rd, 11, 02:47 PM Thread Starter
Gold Lifetime Member
Larry
 
Join Date: Oct 1999
Location: Alamogordo, NM, USA
Posts: 1,034
Unable to Charge AC System

I am trying to charge a 68 with a factory stock R12 system. During the mechanical restoration I did, the entire AC system was disassembled. Has a new, rebuilt compressor and a new receiver. All lines and components were flushed. System holds vacuum.

When I try to charge it, I can only get 7 ounces to go in. The cylinder is not cold, it's in a bath of hot water. The pressure in both low and high side is 85 PSI at 80 degrees ambient with engine not running. Pressures do not change with engine running and compressor clutch engaged. I confirmed that both schraders are being opened by the hose fittings. I even tried to charge directly from the cylinder to the low and then the high side, nothing, no flow.

It acts like there is only 10% of the system's volume available to charge. I can't believe there would be a blockage, in fact, there would have to be two to isolate the rest of the system. How can that be possible? I don't see how I could have assembled the system incorrectly. Everything pretty much falls into place.

I am totally flabbergasted and puzzled on this! Please help!

Larry

Current Project:
69 Z/28 Resto-Mod
Next In Line:
83 Z28 Restoration
69-er is offline  
Sponsored Links
Advertisement
 
post #2 of 21 (permalink) Old Apr 23rd, 11, 03:13 PM
Senior Tech
Hector
 
Join Date: May 2010
Location: Mass
Posts: 835
Re: Unable to Charge AC System

Are you using a good set of gauges...

68 Camaro Coup, BBC ,2457 headers, th400 , ford 9", Hotchkiss connectors,
Speedjester is offline  
post #3 of 21 (permalink) Old Apr 23rd, 11, 03:27 PM
Senior Tech
Hector
 
Join Date: May 2010
Location: Mass
Posts: 835
Re: Unable to Charge AC System

85 is high for the low side...and the system should just balance when the compressor is off...when the compressor is running high side should be more than 85...

If your using a prof set of gauges are you using them correctly... You are closing the high side valve when you are filling by the low side correct.. Otherwise if both valves are open you will balance both high and low side and produce positive pressure into the can... And if it gets high enough the can could burst...

68 Camaro Coup, BBC ,2457 headers, th400 , ford 9", Hotchkiss connectors,
Speedjester is offline  
 
post #4 of 21 (permalink) Old Apr 23rd, 11, 05:56 PM Thread Starter
Gold Lifetime Member
Larry
 
Join Date: Oct 1999
Location: Alamogordo, NM, USA
Posts: 1,034
Re: Unable to Charge AC System

New set of ProSet gauges.

The pressures are with the engine off or on. Both gauges are balanced at 85 PSI which is about right for the static pressure with 80 degree ambient temp.

7 oz is all I can get in with the engine off or on with both valves open with engine off and only low side open when running.

Current Project:
69 Z/28 Resto-Mod
Next In Line:
83 Z28 Restoration
69-er is offline  
post #5 of 21 (permalink) Old Apr 23rd, 11, 06:06 PM
Senior Tech
Hector
 
Join Date: May 2010
Location: Mass
Posts: 835
Re: Unable to Charge AC System

The system should only be balanced with ac off... Once running the high side comes up... If you open up both valves when running you balance both sides and most likely create positive pressure..

Your compressor may be turning but is the clutch engaging correct.. If it's low you might need to energize it with a jumper..to get the clutch to engage
.
Shut your high side off or disconnect it completely.. Start the car.. Energize the compressor so the clutch engages open the bottle then the low pressure side..

68 Camaro Coup, BBC ,2457 headers, th400 , ford 9", Hotchkiss connectors,
Speedjester is offline  
post #6 of 21 (permalink) Old Apr 23rd, 11, 06:20 PM
Super Moderator
Bess-68's rule
 
Everett#2390's Avatar
 
Join Date: Sep 2000
Location: Va Beach VA
Posts: 32,177
Garage
Re: Unable to Charge AC System

A plug/cap on the evap/POA and/or condensor?

Give a man a rescued dog for the health of both their souls. May 2017 ROTM Winner - Thank you!
'
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
CUBS - 2016 World Series Champions - Thank you, Joe Madden enjoy your next chapter.
Everett#2390 is online now  
post #7 of 21 (permalink) Old Apr 23rd, 11, 06:35 PM
Senior Tech
Hector
 
Join Date: May 2010
Location: Mass
Posts: 835
Re: Unable to Charge AC System

Well I re read your post.. You are engaging the clutch... The only thing left would be something blocking the system....could you have left a plug in?? Did u change the orifice tube??

68 Camaro Coup, BBC ,2457 headers, th400 , ford 9", Hotchkiss connectors,
Speedjester is offline  
post #8 of 21 (permalink) Old Apr 23rd, 11, 08:36 PM Thread Starter
Gold Lifetime Member
Larry
 
Join Date: Oct 1999
Location: Alamogordo, NM, USA
Posts: 1,034
Re: Unable to Charge AC System

Quote:
Originally Posted by Speedjester View Post
Well I re read your post.. You are engaging the clutch... The only thing left would be something blocking the system....could you have left a plug in?? Did u change the orifice tube??
Speedjester and Everett,

I thought about that. I'm not sure if it could be possible unless it was a plug down inside a fitting where I didn't see it.

I hope I wouldn't be so stupid to do that. But, I can't think of anything else that would cause it.

I did crack a receiver fitting, it had pressure there. I guess I need to tear into it again.

BTW, it's the old sight glass system, with a POA and expansion valve. I can't remember the name of this type of system! But, they don't have orifice tubes.

Current Project:
69 Z/28 Resto-Mod
Next In Line:
83 Z28 Restoration
69-er is offline  
post #9 of 21 (permalink) Old Apr 23rd, 11, 08:57 PM
Senior Tech
Hector
 
Join Date: May 2010
Location: Mass
Posts: 835
Re: Unable to Charge AC System

Did not know they didn't have orifice tubes... To be honest I'm not to familiar with the older systems.... Figure there basically the same....

Before you go tearing it all down... Maybe you could pull the hose manifold... Block the low side of the maifold..start pulling vacuum and see if you can feel the vacuum building on the high side.. If you can feel vacuum building then the system is clear .... And would look at the compressor





Quote:
Originally Posted by 69-er View Post
Speedjester and Everett,

I thought about that. I'm not sure if it could be possible unless it was a plug down inside a fitting where I didn't see it.

I hope I wouldn't be so stupid to do that. But, I can't think of anything else that would cause it.

I did crack a receiver fitting, it had pressure there. I guess I need to tear into it again.

BTW, it's the old sight glass system, with a POA and expansion valve. I can't remember the name of this type of system! But, they don't have orifice tubes.

68 Camaro Coup, BBC ,2457 headers, th400 , ford 9", Hotchkiss connectors,
Speedjester is offline  
post #10 of 21 (permalink) Old Apr 24th, 11, 05:25 AM
Gold Lifetime Member
Rick
 
Camaro67_rcl's Avatar
 
Join Date: Apr 2006
Location: Philadelphia Pa
Posts: 360
Send a message via Yahoo to Camaro67_rcl
Re: Unable to Charge AC System

Working compressor should show some change in pressures - I'd look closer at that

Rick
67 RS/SS 355, Autogear M21 (w/Overdrive), 8.5w/3.42



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Camaro67_rcl is offline  
post #11 of 21 (permalink) Old Apr 24th, 11, 09:03 AM
Gold Lifetime Member
Jeff
 
yellow69RS's Avatar
 
Join Date: Jul 2007
Location: Aurora, IL
Posts: 5,269
Send a message via Yahoo to yellow69RS
Re: Unable to Charge AC System

Quote:
Originally Posted by 69-er View Post
Speedjester and Everett,
BTW, it's the old sight glass system, with a POA and expansion valve. I can't remember the name of this type of system! But, they don't have orifice tubes.
Since you know that I assume you also know how to charge this system. With the little experience I ever got on these old A/C systems I'll guess you are jumping the low pressure cutoff switch to engage compressor. I always suck the system down, put in one can (thru the low side) with high side closed. then jump sw start car and install the remaining. You're looking for pressures about 30 low side and 100 over Ambient on high side. R12 Freon is 70 PSI at 70 degrees so you 85 PSI sounds about right for a static system.

Jeff
yellow69RS is online now  
post #12 of 21 (permalink) Old Apr 24th, 11, 12:30 PM Thread Starter
Gold Lifetime Member
Larry
 
Join Date: Oct 1999
Location: Alamogordo, NM, USA
Posts: 1,034
Re: Unable to Charge AC System

UPDATE:

I've been disassembling the system. On the POA valve, should I be able to blow through it? I can detect an extremely small flow coming out of the compressor end.

Current Project:
69 Z/28 Resto-Mod
Next In Line:
83 Z28 Restoration
69-er is offline  
post #13 of 21 (permalink) Old Apr 24th, 11, 12:36 PM
Gold Lifetime Member
Daryl
 
1968RallySport's Avatar
 
Join Date: Apr 2007
Location: Northern California
Posts: 956
Garage
Re: Unable to Charge AC System

Here's a link about how to test it.

http://www.autoacforum.com/messagevi...threadid=16311
1968RallySport is offline  
post #14 of 21 (permalink) Old Apr 24th, 11, 12:45 PM Thread Starter
Gold Lifetime Member
Larry
 
Join Date: Oct 1999
Location: Alamogordo, NM, USA
Posts: 1,034
Re: Unable to Charge AC System

Yeah, I have that test procedure too. I might be testing it soon if I don't come up with anything else!

Current Project:
69 Z/28 Resto-Mod
Next In Line:
83 Z28 Restoration
69-er is offline  
post #15 of 21 (permalink) Old Apr 24th, 11, 01:16 PM Thread Starter
Gold Lifetime Member
Larry
 
Join Date: Oct 1999
Location: Alamogordo, NM, USA
Posts: 1,034
Re: Unable to Charge AC System

UPDATE 2:

I didn't want to do this, but with the POA valve removed, I applied shop air to the outlet of the evaporator. Air flowed easily through the system out through the compressor manifold's pressure port. My shop air is going through a desiccant dryer system so I feel confident it didn't overload the system with moisture.

Other than the POA not being able to flow, the rest of the system must be OK. Now I just need to determine if the compressor is OK.

Current Project:
69 Z/28 Resto-Mod
Next In Line:
83 Z28 Restoration
69-er is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome