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Your Step By Step Guide to Compressor Replacement

KB Delta is an expert in understanding compressor valves and compressor valve parts. Rely on KB Delta to provide this helpful guide about compressor replacement.

Compressor Replacement - KB Delta

However, the repaired or replaced compressor could also fail after a few months if the source of the problem was not corrected properly.

For this reason, it is essential to know what can lead to compressor failure to ensure such problems are averted in the near future.

In the same vein, a step-by-step guide to compressor replacement can help you remedy these problems. It will ensure that the replacement you’ve installed does not break down when you least expect it.

Now work with us, and we’ll show you how to replace a compressor or clean a unit after experiencing a compressor burnout.


What Causes Compressor Failure?

System issues cause compressor failure. Some of these issues result from:

  • Charge loss
  • Motor burnout
  • Liquid slugging
  • Replacement issues
  • High condensing pressures
  • Flood back of the refrigerant


What Causes Compressor Burnout?

Compressor burnout can be attributed to the following:

1. Increase in the Compressor Motor Windings’ Temperature:

An increment in the temperature of the compressor’s motor windings or discharge area can lead to burnout.

Here’s why: A high temperature removes the motor windings’ insulation. This causes a loss in its electrical resistance, a short to the ground, as well as an open winding.

Also, high temperatures can cause the oil to break down, and as such, the lubrication provided will be insufficient, which increases friction within internal components.

2. High Condensing Pressures:

The returning gas (suction) cools the compressor, which helps to remove some amount of heat from the compressor’s motor.

However, if there is insufficient returning gas or improper airflow due to the high superheat value of the gas or charge loss, enough heat will not be removed from the motor. As such, it could overheat.

High condensing pressure can also be linked to the following:

  • Faulty fan motor
  • Dirty condensers
  • Incorrectly set fan controls
  • Inadequately sized condensers
  • Recirculation of the condenser air leaving the motor


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Is It Time for Compressor Replacement?

If a compressor grounds out upon testing, then it could be an indication that there are problems even though it may not indicate burnout.

However, the system needs to be cleaned out before the compressor is replaced.

There are 7 steps in compressor replacement:

1. Test the Refrigerant:

An acid test has to be carried out on the refrigerant using the correct oil test kit to ascertain if it is acidic.

This is because some burned-out compressors are acidic (others like compressors with hydrofluorocarbon refrigerants and polyester oils are not acidic if burnt), especially if the refrigerants are chlorinated.

The same applies if mineral oil was used to charge the compressor.

That being the case, if the refrigerant is slightly acidic, use a suction filter dry-out kit to clean the system.

2. Flush the System:

The next step is to flush the system, whether the system is acidic or not.

The aim is to remove winding insulation, burned oil, and other contaminants from the system. There is also a need to remove the TXV to prevent contaminants from being flushed into it.

On the same note, the evaporator and condenser need to be flushed in order for the flushing agent that comes out, in the end, to be as clean as possible. This process can be repeated in all refrigerant lines to ensure that residual oil-locking contaminants are removed from the system.

If they are not removed, they could plug up the unit and thereby contaminate the oil in the newly installed compressor. Also, check the water flow through the condenser loops and pass a descaler through the condenser loops.

3. Check the Oil in Other Compressors:

This is an optional step, but mandatory if the burned-out compressor is part of a parallel group of compressors and uses the same suction & oil equalization with other compressors it is connected to.

If that’s the case, it would also mean that the oil in other compressors may have discolored as a result of overheating or burned oil migrating to these compressors.

There are also chances that if the oil in the compressor is acidic, the oil in others will be acidic as well.

Therefore, the oil in these compressors needs to be checked for discoloration and replaced if need be.

4. Pump out the Refrigerant:

The refrigerant needs to be pumped out. Likewise, if the system is not acidic, but has been adequately flushed, you can install a liquid line drier with activated alumina as well as a molecular sieve desiccant.

For instance, install a catch-all filter drier in the suction line, an access valve on the gauge port, and an oversized liquid-line drier in the liquid line.

On the other hand, if the system was not acidic on testing, you need to install a suction line and remove the drier.

The latter is also required if the refrigerant in the unit is chlorinated. This could cause the acid it produces to cling to the insides, thereby making it difficult to remove.

5. Replace the Compressor:

Here, you can now replace the compressor.

However, you will also need to pump down the system for 24 hours to create a deep vacuum.

After that, the system can be recharged using a virgin refrigerant.

6. Perform System Checks:

After compressor replacement, you need to let it operate for 24 hours.

After that, you can check its acid and pressure drop across the suction drier core.

The system can be left to run for 48 more hours before the acid is rechecked. If there is no acid present, you can proceed to install a standard core as a replacement for the acid core.

Despite this, the unit has to be checked frequently to ensure that there is no acid. If that’s the case, you can proceed to install a felt element in the core and remove the filter.

7. Carry Out Maintenance Regularly:

The system may be up and running, but a good practice is to perform system checks regularly.

It will ensure that the lifespan of the unit is long, and you can easily find the signs of faulty compressors if any is evident.


compressor replacement - KB Delta



A step-by-step guide to compressor replacement will ensure that your newly replaced unit does not develop problems within a short time. You can also be aware of what causes compressor problems instead of just replacing the compressor and leaving it as it is.

In the end, you would’ve successfully improved the performance and lifespan of your compressor.

And feel free to contact KB Delta for all your compressor valve needs and information about compressor valve parts.

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