Started up my truck a few weeks back and I heard a loud pop and hiss...I thought it was just an issue with fuel as the truck was sitting for awhile. Get back in it a week later and run AC and it's not blowing cold at all so I blew something up. Hopefully just a hose. Any way to pressurize the lines with air to leak check?

 

Could have blown a hose or pressure relieve valve on compressor. Had this happen on another vehicle.  If so something maybe causing it to overcharge. Only way I know how to check is with a set of manifold gauges and freon.

 

I ended having a plugged condenser causing on overcharge and it set the pressure relief valve on the a/c compressor off 

Edited August 29, 20178 yr by 01cummins4ever

If you have the gauges you could rig up something on the freon fill line and hook your air compressor to it. I was going to do that to mine but my circumstances changed and I no longer needed to.

,  I would pull a vacuum test on it first just to see if it will hold a vacuum. If not a couple cans of cheap freon should show a leak.  If you don't have the tools they usually can be rented at an auto zone or something. They usually not the best quality but should get the job done. Your pretty much in the dark trying to trouble shoot an a/c system without them.

Wal mart freon is cheap at $4.88 a can.

Do not introduce compressed air into your ac system bad things will happen as in needing to replace the receiver dryer/accumulator because of the moisture in the air. Any time you open the system those should be replaced anyway. Really should be left up to someone who has a/c certification if you are going to be doing much more than using the crap in a can that they pass as freon(more propelents and other junk than anything). The EPA is pretty strict on ac work being performed by unlicensed individuals. Got a few techs in my shop that don't have ac certification and they can't do any ac work with out risk of big fines. Just sayin

1 hour ago, CumminsTech said:

Do not introduce compressed air into your ac system bad things will happen as in needing to replace the receiver dryer/accumulator because of the moisture in the air. Any time you open the system those should be replaced anyway. Really should be left up to someone who has a/c certification if you are going to be doing much more than using the crap in a can that they pass as freon(more propelents and other junk than anything). The EPA is pretty strict on ac work being performed by unlicensed individuals. Got a few techs in my shop that don't have ac certification and they can't do any ac work with out risk of big fines. Just sayin

I cannot disagree with what you say at all. As one who repaired his own and is a neophyte at it, I cant help but wonder why you can buy everything you need to do it almost anywhere. Kind of a conundrum at the least.  

 

Do you know how much of a difference there is between the different brands of freon out there and how you can tell the difference between them.?

You can use compressed air for testing but you'll need to pull vacuum for more time to ensure the system is truly dry again. As for leak checking vacuum test is kind of flawed. Like in my last job the system held vacuum fine. Leaked badly. Vacuum test passed becaused it sucked a bug in the hole of the condenser and blew off after Freon was added.

 

Do not attempt to run the compressor with compressed air. 

Edited August 29, 20178 yr by Mopar1973Man

here's a good article

ac repair.mht

I cant get this article to open, maybe somebody else might have better luck posting it than I

Edited August 30, 20178 yr by 01cummins4ever

Url issue. Yeah I know about it. 

If your going to pressure test best to use nitrogen if you have access to it. It's what I use in our shop. Was just passing on what I was taught about not using compressed air for pressure testing. Spent 4 very boring days at Peterbilt's corporate training facility on HVAC systems and that was a big thing the trainer touched on. Not saying it won't work but like Michael said gonna have to vacuum it a lot longer to make sure it's dry I still would replace the accumulator then if you do use shop air. 

2 hours ago, dripley said:

 

 

Do you know how much of a difference there is between the different brands of freon out there and how you can tell the difference between them.?

No not really. I use straight freon in a 30lb keg on our ac machine. I know theirs propane and other garbage that can damage the ac recovery machine if it's not properly filtered. We try not to work on stuff that has been recharged with the do it yourself came if at all possible 

Edited August 30, 20178 yr by CumminsTech
Spelling

Here is where business and private person draw lines in the sand.

 

Business folks have to play by the rule book and do it the "Right Way". Then there is the "Common Joe" that don't have access to a bunch of fancy tools and machines most here have at least the manifold gauge set and vacuum pump either electric or air driven. Technically to be absolutely perfect about it yes the business side would be right. Since the Common Joe doesn't have the funds or the tools then most times out of ten Common Joe takes a few shortcuts that might cause problems but if they take the extra time you can get away with it. 

 

Using compress air from a compressor that is drained and not been running in awhile should be safe. You'll need to run vacuum longer to draw any moisture out. Still in all any new accumulator, you open the ends up to the atmosphere is no different that using compress air as same just compressed. 

Edited August 30, 20178 yr by Mopar1973Man

5 hours ago, Mopar1973Man said:

Here is where business and private person draw lines in the sand.

 

Business folks have to play by the rule book and do it the "Right Way". Then there is the "Common Joe" that don't have access to a bunch of fancy tools and machines most here have at least the manifold gauge set and vacuum pump either electric or air driven. Technically to be absolutely perfect about it yes the business side would be right. Since the Common Joe doesn't have the funds or the tools then most times out of ten Common Joe takes a few shortcuts that might cause problems but if they take the extra time you can get away with it. 

 

Using compress air from a compressor that is drained and not been running in awhile should be safe. You'll need to run vacuum longer to draw any moisture out. Still in all any new accumulator, you open the ends up to the atmosphere is no different that using compress air as same just compressed. 

Very good point @Mopar1973Man .  I agree, when the system has been opened the accumulator should always be changed.  Most auto parts stores won't give you a warranty on AC components unless you buy an accumulator with it.

 

L8tr

D

2 hours ago, SilverMoose said:

when the system has been opened the accumulator should always be changed

 

Why?

 

So if I opened every joint and installed o-rings you would change the accumalator? I wouldn't. No sense in it. When you place a vacuum on the accumulator you automatically reconditioning the drier as the vacuum is pulling the moisture out of the drier in the accumulator. 

 

 

 

 

21 hours ago, Mopar1973Man said:

 

Why?

 

So if I opened every joint and installed o-rings you would change the accumalator? I wouldn't. No sense in it. When you place a vacuum on the accumulator you automatically reconditioning the drier as the vacuum is pulling the moisture out of the drier in the accumulator. 

 

 

 

 

 

Being uneducated about AC I can not answer that question.  I'm just speaking from experience.  All the components I've changed over the years a new accumulator has been part of it.  I guess it's like  when u get new tires, you get new valve stems wether they're needed or not (very loose analogy).  And the warranty.

 

L8tr

D

Warranty or black death... That's is the only reasons.

Edited August 31, 20178 yr by Mopar1973Man

Damage can occur if there’s excessive moisture inside an A/C system. It can cause corrosion, as well as possibly degrade the performance of the compressor’s lubricating oil.

The receiver/drier or accumulator should be replaced any time the system is opened for service, and most compressor warranties require it. The desiccant is only capable of absorbing a certain amount of moisture, and when the inside of the system and/or the receiver/drier or accumulator are exposed to the atmosphere, the desiccant can become very quickly saturated from humidity in the air. If this occurs, the desiccant is no longer effective, and will not provide future protection. Additionally, the filter inside the receiver/drier could be restricted by debris that may have been inside the system. This could diminish refrigerant and oil flow.

29 minutes ago, CumminsTech said:

The receiver/drier or accumulator should be replaced any time the system is opened for service, and most compressor warranties require it. The desiccant is only capable of absorbing a certain amount of moisture, and when the inside of the system and/or the receiver/drier or accumulator are exposed to the atmosphere, the desiccant can become very quickly saturated from humidity in the air. If this occurs, the desiccant is no longer effective, and will not provide future protection. Additionally, the filter inside the receiver/drier could be restricted by debris that may have been inside the system. This could diminish refrigerant and oil flow.

1

 

So during the time you open the new accumulator to the atmosphere to install its no different, you might as well throw that one away too using that logic. This why the vacuum is placed on the system so the desiccant is renewed and dried out. So now if you look up the boiling point of water in a vacuum you see the water will boil at below 100*F.

 

Technical the only way to install the new accumulator without moisture ever getting to the desiccant is to have the manufactured produce he accumulator unit in a vacuum and seal the unit in a vacuum chamber for shipping. Now load the truck up in an air tight chamber and pull a vacuum on the entire truck and then install the new unit inside this vacuum chamber. Far fetched?! Sure... A/C work if it was this critical we all be paying through the nose and most of us wouldn't have A/C today because it would be too expensive.

 

Again this is scare tactics. Accumulator desiccant can be renewed simply by a vacuum. Yes, warranties REQUIRE the replacement of the orifice tube and the accumlator for compressor replacement. If you open the system to replace o-ring you do not have to replace the orifice tube and accumulator again. Again all you have to do is pull a strong vacuum (>27 inHg) on the system for an extended period of time to renew the desiccant.

 

Now with black death that is a totally different story. Black death is when a compressor is ground up and pumped through the system. This REQUIRED a full replacement of orifice tube and accumulator this is to ensure no debris damages the new compressor. Some manufacturers require the condenser to be replaced because of the possibility of debris being caught up in the tubing of the condenser. Black death is a PITA no matter how you look at it either it's expensive to replace everything or attempting to flush out the system with A/C flush solvent which is expensive. 

Edited August 31, 20178 yr by Mopar1973Man

The minute or so that it is open before you install the lines on it  is not going to make a difference that can be recovered with a vacuum. it is when you have everything disconnected for hours on end replacing everything and the original is open to atmosphere the whole time is why it should be replaced. But to the each their own. I replace them.

32 minutes ago, CumminsTech said:

when you have everything disconnected for hours on end

 

Now that is a different story. If the system is open for an extended period of time. This is a new issue. Depending on condition and how long its left open to the elements. So if someone broke open the system and left it for days now even I would be worried about debris and other issues. But during the time of servicing HVAC system for o-ring or heater core. Just cap the ends and proceed. No different than how the accumulator is shipped to you from a parts store.

 

In the time to service, an o-ring is not an issue. If you're replacing a compressor you going to be replacing an accumulator and orifice anyway for warranty.  Service a heater core. Plug your tube ends and proceed as typically and place a vacuum on the system and reuse the accumulator. 

Edited August 31, 20178 yr by Mopar1973Man

Well. I since I don't have a vac pump, I will have to take it somewhere to find the leak I guess. Have no real idea whether it has popped off due to a condensor clog, crapped out compressor, or just a busted line.