If the original condenser on the vehicle looks like this:
AND
Your replacement condenser looks like this:
YOU CANNOT USE THE SAME REFRIGERANT CHARGE!
The parallel flow style condenser may require ~20% less refrigerant than the piccolo style condenser.
Using the factory recommended charge specified for the piccolo condenser will overcharge and damage the new condenser.
For further guidance on verifying the proper refrigerant charge, watch the video below.
Using the factory recommended charge specified for the piccolo condenser will overcharge and damage the new condenser.
For further guidance on verifying the proper refrigerant charge, watch the video below.
WATCH
Replacing the Condenser: Check the Charge Before You Install
How to verify condenser charge by temperature testing
Replacing the Condenser: Check the Charge Before You Install
How to verify condenser charge by temperature testing
Video Transcript:
The need to replace the condenser when replacing a failed compressor on later model vehicles has been recommended for several years. Generally, a 2000 or later model vehicle will have some style of "multi flow" or parallel flow condenser. The piccolo tube style used by Ford had 30 to 40 6mm diameter tubes in two rows grouped in manifolds, 10-12 at a time. Although effective for heat exchange, the grouping of these manifolds made flushing ineffective because contaminates in the condenser could not be thoroughly cleared.
The parallel flow condenser is designed with 20-40 flat tubes attached to zoned header pipes that direct refrigerant back and forth across the condenser 3 to 4 times before exiting. Each individual tube may contain 10-18 passages that can measure less than 1mm in diameter. The result is 400-600 extremely small passages that can stop up from debris coming from the failing compressor, restricting refrigerant flow, causing high head pressure, and further damaging the compressor. THESE RESTRICTIONS ARE IMPOSSIBLE TO CLEAR WITH FLUSH. And failure to replace the condenser will likely cause repeat compressor failure.
High head pressure due to a restriction in the condenser may not be evident if the high side charging port is located between the condenser and evaporator. However, condenser efficiency CAN be determined by temperature testing. A parallel flow condenser should have a temperature change of 35 to 50 degrees from inlet to outlet. A temperature difference over 60 degrees indicates a restriction in the condenser which means the condenser needs to be replaced.
Once you have identified the correct replacement condenser and compressor and thoroughly flushed the system prior to installation, special attention must be given to any differences in tube size and tube count between the original condenser and the replacement condenser. The factory refrigerant charge CANNOT be used if there is ANY difference between the two condensers. Manufacturers generally design replacement condensers to match the external dimensions of the original equipment, but tube size and count may vary. Most condenser manufacturers now offer a parallel flow style condenser as a replacement for the factory piccolo style condenser.
The installer will be responsible for identifying this change in condenser style and determining the proper refrigerant charge for the system. The parallel flow condenser will typically require less refrigerant than the piccolo style. If the factory charge specified for the original piccolo style condenser is used for the replacement parallel flow style condenser, the system will be overcharged and liquid refrigerant will build up in the bottom of the condenser, preventing condensation and reducing the available area for heat transfer. For older systems, the difference in refrigerant charge will be very significant.
Temperature testing is the BEST method to determine the correct charge for your new condenser. The installer’s goal will be to maximize the temperature drop across the condenser, ideally a 35 to 50 degree change from inlet to outlet. Temperature at the evaporator can also be monitored. Take note that temperature testing at the evaporator will be different for an orifice tube system versus an expansion valve system.
In the orifice tube system, it is imperative that the evaporator stays flooded with liquid refrigerant. This occurs when the temperature on the line behind the orifice tube and the temperature of the line coming out of the evaporator before the accumulator is the same or within 2 degrees.
On the expansion valve system, the suction line coming out of the firewall should be monitored while refrigerant charge is reduced to achieve the lowest possible temperature. This temperature change can also be monitored through the center dash vents.
To Recap:
The need to replace the condenser when replacing a failed compressor on later model vehicles has been recommended for several years. Generally, a 2000 or later model vehicle will have some style of "multi flow" or parallel flow condenser. The piccolo tube style used by Ford had 30 to 40 6mm diameter tubes in two rows grouped in manifolds, 10-12 at a time. Although effective for heat exchange, the grouping of these manifolds made flushing ineffective because contaminates in the condenser could not be thoroughly cleared.
The parallel flow condenser is designed with 20-40 flat tubes attached to zoned header pipes that direct refrigerant back and forth across the condenser 3 to 4 times before exiting. Each individual tube may contain 10-18 passages that can measure less than 1mm in diameter. The result is 400-600 extremely small passages that can stop up from debris coming from the failing compressor, restricting refrigerant flow, causing high head pressure, and further damaging the compressor. THESE RESTRICTIONS ARE IMPOSSIBLE TO CLEAR WITH FLUSH. And failure to replace the condenser will likely cause repeat compressor failure.
High head pressure due to a restriction in the condenser may not be evident if the high side charging port is located between the condenser and evaporator. However, condenser efficiency CAN be determined by temperature testing. A parallel flow condenser should have a temperature change of 35 to 50 degrees from inlet to outlet. A temperature difference over 60 degrees indicates a restriction in the condenser which means the condenser needs to be replaced.
Once you have identified the correct replacement condenser and compressor and thoroughly flushed the system prior to installation, special attention must be given to any differences in tube size and tube count between the original condenser and the replacement condenser. The factory refrigerant charge CANNOT be used if there is ANY difference between the two condensers. Manufacturers generally design replacement condensers to match the external dimensions of the original equipment, but tube size and count may vary. Most condenser manufacturers now offer a parallel flow style condenser as a replacement for the factory piccolo style condenser.
The installer will be responsible for identifying this change in condenser style and determining the proper refrigerant charge for the system. The parallel flow condenser will typically require less refrigerant than the piccolo style. If the factory charge specified for the original piccolo style condenser is used for the replacement parallel flow style condenser, the system will be overcharged and liquid refrigerant will build up in the bottom of the condenser, preventing condensation and reducing the available area for heat transfer. For older systems, the difference in refrigerant charge will be very significant.
Temperature testing is the BEST method to determine the correct charge for your new condenser. The installer’s goal will be to maximize the temperature drop across the condenser, ideally a 35 to 50 degree change from inlet to outlet. Temperature at the evaporator can also be monitored. Take note that temperature testing at the evaporator will be different for an orifice tube system versus an expansion valve system.
In the orifice tube system, it is imperative that the evaporator stays flooded with liquid refrigerant. This occurs when the temperature on the line behind the orifice tube and the temperature of the line coming out of the evaporator before the accumulator is the same or within 2 degrees.
On the expansion valve system, the suction line coming out of the firewall should be monitored while refrigerant charge is reduced to achieve the lowest possible temperature. This temperature change can also be monitored through the center dash vents.
To Recap:
- If there is any difference in condenser style, tube size or tube count between the original condenser and replacement condenser, you MUST take caution. Using the original factory recommended refrigerant charge will damage the new compressor.
- Temperature testing is the best method to verify proper refrigerant charge.
- For normal operation there should be a 35 to 50 degree temperature difference from inlet to outlet
- If the temperature difference from inlet to outlet is 60 degrees or higher, there is an internal restriction in the condenser.
- If the temperature difference from inlet to outlet is 25 degrees or less, the condenser is overcharged. This could also be a sign of poor airflow across the condenser and radiator.
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