Bryan Orr, Eric Mele, and Joe Shearer teach the Kalos apprentices (and the YouTube audience) about HVAC system burnout. We cover the basics of burnout and dive into cleanout procedures. We also look at the Emerson-Copeland Bulletin AE24-1105 for some information inside manufacturer literature. You can read that bulletin at the following link: https://climate.emerson.com/CPID/GRAPHICS/Types/AEB/ae1105.pdf.
Burnout is a type of compressor failure where there is electrical arcing. A short-circuit to ground or from winding to winding burns the oil and refrigerant in the compressor. Burning that oil and refrigerant results in acids, wax, and other nasty residues inside and around the failed compressor. (Keep in mind that compressors use POE oil nowadays. So, if you swap a compressor on a system with mineral oil, the replacement will likely come with POE oil.)
Burnout is especially common in cases where moisture remains in the system due to improper evacuation. So, pulling good vacuums is a preventative measure for burnout. Solid contaminants and mechanical failures may also lead to burnout. However, not all contaminants are related to burnout. Non-condensables also do NOT contribute to burnout.
Emerson recommends the filter-dryer cleaning procedure. Every time you open a system for service, replace the liquid line filter-dryer. (Make sure to use a bi-flow dryer for heat pumps. If you use Emerson dryers, Joe Shearer recommends using bi-flow dryers on heat pumps AND straight-cool systems.) Replace the suction dryers, too. Eric Mele recommends slightly oversizing the dryers.
Some sources may recommend using charcoal in HH dryers to eliminate wax. However, we generally prefer using EK dryers with the most desiccant and activated alumina.
You will also want to clean filters and screens. In many cases, you may straight-pipe the dryers from their previous locations and install them in new locations. Emerson also recommends using a moisture indicator or sight glass for the cleaning procedure. While that is a good practice, it is not always necessary, especially in residential applications.
With the dryers installed, you can evacuate the system. After that, start the compressor and put the system in operation.
The bulletin recommends operating and watching the unit for 48 hours. Like some other practices, this practice is feasible for commercial HVAC but impractical for residential HVAC. In those cases, you don't need to follow the bulletin procedures to a T for residential HVAC (but they are still good to do if you have the time, money, and resources). Using your best judgment and communicating with the customer to develop a plan of action is the best you can do.
At a minimum, however, technicians must go back and check the pressure drop across the suction dryer, especially if they choose to leave it in permanently. If the pressure drop exceeds 3 PSI after stabilizing, you must remove the suction dryer.
Acid inhibition (Acid Scavenger/Acid-Away) products for treating burnout are controversial. These products react with the burnout acid and should neutralize, but you can decrease the compressor's lubrication abilities if you add too much. In short, they work under some circumstances but can also make things worse under other circumstances.
We also discuss pipe wipers, accumulators, and aftermarket flush as they relate to burnouts, even though Emerson doesn't recommend those in its literature. Joe Shearer doesn't necessarily like to have a suction dryer in the system at all times, but he replaces the suction accumulator when he cleans up burnouts. If the system is a heat pump, the reversing valve can also be affected by burnout or get in the way. So, it's best to pay attention to accessories on the suction line near the compressor inlet.
On the electrical side, make sure to replace the contactor and capacitor after a burnout on a single-phase unit. Check what the new compressor's capacitors are to make sure you get the correct one. Demonstrate extra caution when replacing the contactor if you have a crankcase heater. You can also make burnout worse if you keep resetting the circuit breaker without isolating the true cause of the burnout and attempting to fix it. Each time you reset the breaker, the short and arc will happen again and cause more burnout.
In the end, there is not a single one-size-fits-all solution for cleaning burnout, but it is important to discover why the compressor failed in the first place and prevent it from happening again.
Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.
Burnout is a type of compressor failure where there is electrical arcing. A short-circuit to ground or from winding to winding burns the oil and refrigerant in the compressor. Burning that oil and refrigerant results in acids, wax, and other nasty residues inside and around the failed compressor. (Keep in mind that compressors use POE oil nowadays. So, if you swap a compressor on a system with mineral oil, the replacement will likely come with POE oil.)
Burnout is especially common in cases where moisture remains in the system due to improper evacuation. So, pulling good vacuums is a preventative measure for burnout. Solid contaminants and mechanical failures may also lead to burnout. However, not all contaminants are related to burnout. Non-condensables also do NOT contribute to burnout.
Emerson recommends the filter-dryer cleaning procedure. Every time you open a system for service, replace the liquid line filter-dryer. (Make sure to use a bi-flow dryer for heat pumps. If you use Emerson dryers, Joe Shearer recommends using bi-flow dryers on heat pumps AND straight-cool systems.) Replace the suction dryers, too. Eric Mele recommends slightly oversizing the dryers.
Some sources may recommend using charcoal in HH dryers to eliminate wax. However, we generally prefer using EK dryers with the most desiccant and activated alumina.
You will also want to clean filters and screens. In many cases, you may straight-pipe the dryers from their previous locations and install them in new locations. Emerson also recommends using a moisture indicator or sight glass for the cleaning procedure. While that is a good practice, it is not always necessary, especially in residential applications.
With the dryers installed, you can evacuate the system. After that, start the compressor and put the system in operation.
The bulletin recommends operating and watching the unit for 48 hours. Like some other practices, this practice is feasible for commercial HVAC but impractical for residential HVAC. In those cases, you don't need to follow the bulletin procedures to a T for residential HVAC (but they are still good to do if you have the time, money, and resources). Using your best judgment and communicating with the customer to develop a plan of action is the best you can do.
At a minimum, however, technicians must go back and check the pressure drop across the suction dryer, especially if they choose to leave it in permanently. If the pressure drop exceeds 3 PSI after stabilizing, you must remove the suction dryer.
Acid inhibition (Acid Scavenger/Acid-Away) products for treating burnout are controversial. These products react with the burnout acid and should neutralize, but you can decrease the compressor's lubrication abilities if you add too much. In short, they work under some circumstances but can also make things worse under other circumstances.
We also discuss pipe wipers, accumulators, and aftermarket flush as they relate to burnouts, even though Emerson doesn't recommend those in its literature. Joe Shearer doesn't necessarily like to have a suction dryer in the system at all times, but he replaces the suction accumulator when he cleans up burnouts. If the system is a heat pump, the reversing valve can also be affected by burnout or get in the way. So, it's best to pay attention to accessories on the suction line near the compressor inlet.
On the electrical side, make sure to replace the contactor and capacitor after a burnout on a single-phase unit. Check what the new compressor's capacitors are to make sure you get the correct one. Demonstrate extra caution when replacing the contactor if you have a crankcase heater. You can also make burnout worse if you keep resetting the circuit breaker without isolating the true cause of the burnout and attempting to fix it. Each time you reset the breaker, the short and arc will happen again and cause more burnout.
In the end, there is not a single one-size-fits-all solution for cleaning burnout, but it is important to discover why the compressor failed in the first place and prevent it from happening again.
Read all the tech tips, take the quizzes, and find our handy calculators at https://www.hvacrschool.com/.
Dude had fake Fluke leads or some odd ball specialty leads. I've never had a set of Fluke leads that had any issues that weren't caused by poor treatment. Service area Kanata??
I really have to ask. I did a flush on a 404A , captube , 3 door display freezer and I am wondering if leftover flush would cause a high suction pressure and superheat? After flushing, this 404A system is running between 30PSIG and down to 25 at system is satisfied. It is running good superheat when its satisfied.
you guys are funny. no mention though difference of running burn out or starting burn out. Vacuum pumps are made to remove CRAPP(Contaminates Resulting in Addition Partial Pressure). But they can get CRUD(Contaminates Resulting in Undesirable Deposits) in them as Joe mentioned below in his reply, and has happened to me. But only once, many years ago. Funny that Bryan does not have a pool or hot tub. He did build a radio tower though. Sent radio signals into space. That is where the anomaly Jim Bergman came from.
can you make a similar video about how to clear liquid line restriction that is not due to filter dryer
The sporlan dryer pdf page 4, says that acid is usually present as a gas in the system
Great video. You are master in hvac I hope you will keep making videos
Great video. On sealed systems appliances I prefer the sporlan catch all driers over the pencil driers.