AC Help
#12
10-20-2019, 05:29 PM
Doh... I should have thought about jumpering the low pressure switch connector - Captain Obvious.
The pressure on the low side is flat zero with the engine off or on - even with the compressor jumpered.
I get from your reply that the switch is a pressure switch and that there needs to be a minimum charge to close the switch - I bought a new bottle of refrigerant and will hook it up when my kid gets back - it's his daily driver right now.
I checked on the price of a whole accumulator is $24 so that's good. If the system is completely empty of course I can't rule out a leak, large or small.
@Christine - thanks for the tip on replacing just the switch - good to know.
Appreciate the help!
The pressure on the low side is flat zero with the engine off or on - even with the compressor jumpered.
I get from your reply that the switch is a pressure switch and that there needs to be a minimum charge to close the switch - I bought a new bottle of refrigerant and will hook it up when my kid gets back - it's his daily driver right now.
I checked on the price of a whole accumulator is $24 so that's good. If the system is completely empty of course I can't rule out a leak, large or small.
@Christine - thanks for the tip on replacing just the switch - good to know.
Appreciate the help!
You either have:
A failed low pressure switch at the accumulator
Insufficient pressure at that switch to close it (usually > 30-50 psi)
A wiring or connector problem
What is the low pressure reading at the low pressure port with the engine off?
What happens if you pull the connector at the low pressure switch and jumper it with a paper clip for just a couple of seconds? Does the compressor clutch engage?
George
A failed low pressure switch at the accumulator
Insufficient pressure at that switch to close it (usually > 30-50 psi)
A wiring or connector problem
What is the low pressure reading at the low pressure port with the engine off?
What happens if you pull the connector at the low pressure switch and jumper it with a paper clip for just a couple of seconds? Does the compressor clutch engage?
George
#13
10-20-2019, 08:53 PM
Why did you replace the accumulator?
Was the system fully charged and now its completely empty? If so, you must find the location of the leak.If you don't have an electronic detector, look for small amounts of oil leaks and/or use a spray bottle of soapy water around connections, joints, etc.
George
Was the system fully charged and now its completely empty? If so, you must find the location of the leak.If you don't have an electronic detector, look for small amounts of oil leaks and/or use a spray bottle of soapy water around connections, joints, etc.
George
#14
10-21-2019, 04:01 AM
No the accumulator was not changed. Only troubleshooting so far. The vehicle is new to me and I have only owned it for 10 days. AC was not blowing cold when I bought it so I don't have the history.
Why did you replace the accumulator?
Was the system fully charged and now its completely empty? If so, you must find the location of the leak.If you don't have an electronic detector, look for small amounts of oil leaks and/or use a spray bottle of soapy water around connections, joints, etc.
George
Was the system fully charged and now its completely empty? If so, you must find the location of the leak.If you don't have an electronic detector, look for small amounts of oil leaks and/or use a spray bottle of soapy water around connections, joints, etc.
George
#15
10-21-2019, 09:22 AM
I’m getting the OP and OP2 mixed up. This should have been a new thread. In any event I reread the thread to get it straight.
if you have zero pressure in the system then there is definitely a leak and you need to find it. Also if there is zero pressure then the system should charge to the same pressure as the can of refrigerant when attached. That pressure varies with outside temp. That’s not enough for a full charge, the system has to be started to take in the rest of the charge but if nothing is going in then something is wrong. Faulty can, faulty shader valve, can is empty, etc.
sisnce the system is at zero pressure then it may be contaminated. After the leak is discovered and fixed, the system will have to be evacuated and charged properly to the weight on the nameplate under the hood. There is a chance that just charging it will work ok but air and moisture in the system can cause a failure of the compressor or sub standard cooling and if you have to open the system to fix the leak then there will be contaminants in the system.
George
if you have zero pressure in the system then there is definitely a leak and you need to find it. Also if there is zero pressure then the system should charge to the same pressure as the can of refrigerant when attached. That pressure varies with outside temp. That’s not enough for a full charge, the system has to be started to take in the rest of the charge but if nothing is going in then something is wrong. Faulty can, faulty shader valve, can is empty, etc.
sisnce the system is at zero pressure then it may be contaminated. After the leak is discovered and fixed, the system will have to be evacuated and charged properly to the weight on the nameplate under the hood. There is a chance that just charging it will work ok but air and moisture in the system can cause a failure of the compressor or sub standard cooling and if you have to open the system to fix the leak then there will be contaminants in the system.
George
#16
10-22-2019, 05:35 AM
Yeah - sorry... Really bad Netiquette to hijack a thread like this - my bad...
I am pretty clear on things now. I am a pretty good wrench but have never delved into the mysteries of AC much other than the theory. I will try to chase down the source of leak (there must be one) and do repairs. Then I get that a purge and fill is the right answer. I sprayed soapy water on all the fittings topside but haven't been underneath at the radiator (condensor) fittings.
Is there a tool I can borrow from Autozone to pressurize the system without running the engine? That would help in the next phase.
I will break my thread out to a new one with any updates this weekend.
Thanks again for the AC lesson. I also have an S10 pickup with the same symptoms. Both compressors work when LP switch is jumpered anf both have zero pressure so likely both have leaks.
I am pretty clear on things now. I am a pretty good wrench but have never delved into the mysteries of AC much other than the theory. I will try to chase down the source of leak (there must be one) and do repairs. Then I get that a purge and fill is the right answer. I sprayed soapy water on all the fittings topside but haven't been underneath at the radiator (condensor) fittings.
Is there a tool I can borrow from Autozone to pressurize the system without running the engine? That would help in the next phase.
I will break my thread out to a new one with any updates this weekend.
Thanks again for the AC lesson. I also have an S10 pickup with the same symptoms. Both compressors work when LP switch is jumpered anf both have zero pressure so likely both have leaks.
I’m getting the OP and OP2 mixed up. This should have been a new thread. In any event I reread the thread to get it straight.
if you have zero pressure in the system then there is definitely a leak and you need to find it. Also if there is zero pressure then the system should charge to the same pressure as the can of refrigerant when attached. That pressure varies with outside temp. That’s not enough for a full charge, the system has to be started to take in the rest of the charge but if nothing is going in then something is wrong. Faulty can, faulty shader valve, can is empty, etc.
sisnce the system is at zero pressure then it may be contaminated. After the leak is discovered and fixed, the system will have to be evacuated and charged properly to the weight on the nameplate under the hood. There is a chance that just charging it will work ok but air and moisture in the system can cause a failure of the compressor or sub standard cooling and if you have to open the system to fix the leak then there will be contaminants in the system.
George
if you have zero pressure in the system then there is definitely a leak and you need to find it. Also if there is zero pressure then the system should charge to the same pressure as the can of refrigerant when attached. That pressure varies with outside temp. That’s not enough for a full charge, the system has to be started to take in the rest of the charge but if nothing is going in then something is wrong. Faulty can, faulty shader valve, can is empty, etc.
sisnce the system is at zero pressure then it may be contaminated. After the leak is discovered and fixed, the system will have to be evacuated and charged properly to the weight on the nameplate under the hood. There is a chance that just charging it will work ok but air and moisture in the system can cause a failure of the compressor or sub standard cooling and if you have to open the system to fix the leak then there will be contaminants in the system.
George
#17
10-22-2019, 09:05 AM
Pressure testing is done with dry nitrogen with a small amount of refrigerant for detecting. Once pressurized then all joints and other suspect areas are swept with an electronic detector. In olden days, that was a flame detector. A poor mans substitute is a spray bottle of soapy water. My favorite which I do before I use my leak detector is run my finger around all areas looking for a very small amount oil oil as it leaks out with the refrigerant. The most common locations are the Schraeder valves and anywhere that there is an o ring. Second most common is probably the belly band of the compressor. After that hoses, evaporator, condenser. Keep in mind that it’s against the law to intentionally vent more than a minimum amount of refrigerant into the atmosphere. That and cost is why nitrogen is used for leak testing. Don’t run the system for extended periods with no gas in the system as there will be improper cooling and oil movement.
George
George
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