A/C Question
Thread Starter
Burning Brakes
Joined: Sep 2006
Posts: 1,142
Likes: 0
From: Spring Grove Illinois
A/C Question
My engine is done and I'm wondering if there is some way to force the compressor to engage..It doesnt have freon but i wont to may sure it's O.K......Also with those do it yourself kits,,they must be used with the engine running right?? The low pressure switch keeps the compressor from comming on so if I try to fill it with the kit with the engine running will it fill??...I tried to fill w/o the engine running and it wouldnt fill.. Thanks In Advance
Racer
Joined: Sep 2005
Posts: 271
Likes: 0
From: New Freedom PA
A/c Refill
My engine is done and I'm wondering if there is some way to force the compressor to engage..It doesnt have freon but i wont to may sure it's O.K......Also with those do it yourself kits,,they must be used with the engine running right?? The low pressure switch keeps the compressor from comming on so if I try to fill it with the kit with the engine running will it fill??...I tried to fill w/o the engine running and it wouldnt fill.. Thanks In Advance
assuming you have done a proper 45 minute pump down.(Evacuation)this is a MUST!
1. Locate the low presure switch at the Accumulator(Receiver Drier)
2. Hook up your A/C gauges and have your Refrigerant ready to be installed.
3. Start engine and turn A/C on.
4. Remove wiring connector at Low Pressure switch and jump both terminals in the harness.
5. Start Refrigerant installation slowly , Compressor will cycle on and off very quickly until fully recharged.
6. After the first LB is installed you can remove the jumper and re-plug harness back into the low pressure switch.
7. Monitor outlet vent temp with a thermometer.
Best way to recharge any system is to use a A/C machine that weighs the freon, But it can be done with the old hose and gauge method if you are carefull. try not to over charge your system, High working system pressure will kill a compressor.
GOOD LUCK
Desert
Last edited by Desert1957; Mar 13, 2007 at 08:11 AM. Reason: add info
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
If the system was opened or exposed to the atmosphere, you need to suck the air/moisture out of it first. Mix refrigerant with either and you can blow it up (and yourself with it). Mixing two different refrigerants together can have the same effect - you need to make sure it's empty before trying something different.
You can disconnect and jumper the low pressure switch harness with a paper clip to see if the compressor will engage. That is of course if there's any oil left in it. Otherwise the compressor can seize and that will pretty much ruin everything - so if you do this and don't know if there's anything lubricating the compressor, do it for only a brief moment. As long as that harness has continuity, the compressor is going to remain engaged.
You can disconnect and jumper the low pressure switch harness with a paper clip to see if the compressor will engage. That is of course if there's any oil left in it. Otherwise the compressor can seize and that will pretty much ruin everything - so if you do this and don't know if there's anything lubricating the compressor, do it for only a brief moment. As long as that harness has continuity, the compressor is going to remain engaged.
Thread Starter
Burning Brakes
Joined: Sep 2006
Posts: 1,142
Likes: 0
From: Spring Grove Illinois
Thanks THe A/c unit was compleatly off along with the lines...So there is nothing in it..I put compressor oil in it and wanted to try to recharge it....so I'll cycle it while the engine is running untill I get a can of ref in it...Does this sound O.K. to do
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
No - it's not a safe practice to mix refigerant and air/moisture and leaving junk in it isn't going to make any cold air. It does have a high pressure switch so if the system pressure goes through the stratosphere, you hope it shuts down. Much better to vacuum/boil all of the bad stuff out of it first. You can buy a $10 displacement vacuum pump (if you have a good size compressor) from Harbor Freight Tools or you can get innovative and hookup the PCV side of your engine to a Manifold Gage Set or you can use an old compressor out of refrigerator to act as a vacuum pump. The important thing is to do it first.
Racer
Joined: Sep 2005
Posts: 271
Likes: 0
From: New Freedom PA
No - it's not a safe practice to mix refigerant and air/moisture and leaving junk in it isn't going to make any cold air. It does have a high pressure switch so if the system pressure goes through the stratosphere, you hope it shuts down. Much better to vacuum/boil all of the bad stuff out of it first. You can buy a $10 displacement vacuum pump (if you have a good size compressor) from Harbor Freight Tools or you can get innovative and hookup the PCV side of your engine to a Manifold Gage Set or you can use an old compressor out of refrigerator to act as a vacuum pump. The important thing is to do it first.
with the first half of this post , do it right , rent or buy a PROPER A/C Vacum Pump to evacuate the system.Desert
