New condensing unit-drier question

[plea5ehelp]

I had a new condensing unit put in. Does the installer need to come out after a month and put in a new dryer? He says he put in a line dryer but not a suction dryer. Is that a problem?

[beenthere]

Made this its own thread.
You are not permitted to post in other peoples threads in the AOP forums. Please read our site rules, thank you.

[BaldLoonie]

Only if you put a new outdoor unit on a contaminated lines & coil. Then he should have put in a suction drier too.

[skippedover]

The purpose of a liquid line dryer is to collect minute bits of debris or to absorb small traces of moisture that could be now or in the future, in the system. Ideally the liquid line dryer is installed indoors near where it enters the air handler. A suction line dryer is installed in situations where larger amounts of contaminants are likely to be found. As Baldloonie stated, this is not the case unless the old compressor was a burn-out electrically. If it was, then a suction line dryer should be installed for a short period of time, then removed and/or changed as necessary. After the final removal, an acid neutralizer should be added to the system to prevent any remaining residue from starting a new round of contamination leading to a new burn out. It is my personal habit to install a single vial of acid neutralizer whenever I'm changing out a compressor or condenser, just for a little added insurance that some acid was present, though testing did not reveal it.

[plea5ehelp]

This condensing unit was replaced because of multiple compressor failures with the old condensing unit. The coil has already been replaced. I'm afraid the whole system is somehow contaminated. Should I insist the installer come back out and put in a suction dryer,then come back out in a month and remove the dryer andadd acid neutralizer? Is there anything that can be done to asure the new(now two month old) condensing unit will not fail? Thanks

it

The purpose of a liquid line dryer is to collect minute bits of debris or to absorb small traces of moisture that could be now or in the future, in the system. Ideally the liquid line dryer is installed indoors near where it enters the air handler. A suction line dryer is installed in situations where larger amounts of contaminants are likely to be found. As Baldloonie stated, this is not the case unless the old compressor was a burn-out electrically. If it was, then a suction line dryer should be installed for a short period of time, then removed and/or changed as necessary. After the final removal, an acid neutralizer should be added to the system to prevent any remaining residue from starting a new round of contamination leading to a new burn out. It is my personal habit to install a single vial of acid neutralizer whenever I'm changing out a compressor or condenser, just for a little added insurance that some acid was present, though testing did not reveal it.

[second opinion]

This condensing unit was replaced because of multiple compressor failures with the old condensing unit. The coil has already been replaced. I'm afraid the whole system is somehow contaminated. Should I insist the installer come back out and put in a suction dryer,then come back out in a month and remove the dryer andadd acid neutralizer? Is there anything that can be done to asure the new(now two month old) condensing unit will not fail? Thanks

it

The cause of the compressor failures should be determined through diagnostics. Compressors do not just die, something is causing the failures and by having multiple failures and nothing being changed but the compressor is a good indication that the new one will also fail.

As for the drier, if it was a mechanical failure the liquid line dryer is fine, but if the compressor had an electrical failure, "burn out" then a suction line drier is required for clean up of the acid and must be removed after 72 hours of run time along with an acid test to see if system is clear of acid and if not procedure should be repeated.

[plea5ehelp]

Replacing the entire condensing unit was supposed to solve the compressor problem, since a new condensing unit would not be contaminated. I am now wondering if the new condensing unit( and therefore the compressor) could become contaminated from the coil or lines.should I insist on the suction dryer/acid neutralizer or just trust that the installer did things correctly,even though the original system &/or installation 5years ago was obviously flawed?How should I proceed?thanks

[jaypslugger]

If you experienced multple failures and they have all been electrical, an acid condition likely exists. At the very least, an acid test should have been performed in order to prevent condemning the replacement units to the same fate.

The problem is that the oil, which travels throughout the system, becomes acidic when the compressor windings "burn out". The acid is a result of moisture in the system combined with high temperatures. When the condensing unit is replaced, some of the contaminated oil from the previous unit is still elsewhere in the system. When the new unit is started up, that contaminated oil is drawn back to the compressor, and the stage is set for motor insulation and winding breakdown (in other words, a new unit).

Before the new condensing unit is installed, a procedure known as an acid clean up should be performed, along with installing a suction line drier (in addition to the liquid line drier). The suction drier may or may not remain in the system, depending upon how badly contaminated the oil was. I would probably remove yours, and perform another acid test. As Skip mentioned, neutralizer is a good idea as well.

[plea5ehelp]

So what should be done now?The new condensing unit was put in 2months ago.Should the line dryer be replaced in addition to a suction drier installed?Then when should the suction drier be taken out?Should the acid neutralizer be added &/or an acid test? Is my new condensing unit now ruined? Thanks

If you experienced multple failures and they have all been electrical, an acid condition likely exists. At the very least, an acid test should have been performed in order to prevent condemning the replacement units to the same fate.

The problem is that the oil, which travels throughout the system, becomes acidic when the compressor windings "burn out". The acid is a result of moisture in the system combined with high temperatures. When the condensing unit is replaced, some of the contaminated oil from the previous unit is still elsewhere in the system. When the new unit is started up, that contaminated oil is drawn back to the compressor, and the stage is set for motor insulation and winding breakdown (in other words, a new unit).

Before the new condensing unit is installed, a procedure known as an acid clean up should be performed, along with installing a suction line drier (in addition to the liquid line drier). The suction drier may or may not remain in the system, depending upon how badly contaminated the oil was. I would probably remove yours, and perform another acid test. As Skip mentioned, neutralizer is a good idea as well.

[second opinion]

So what should be done now?The new condensing unit was put in 2months ago.Should the line dryer be replaced in addition to a suction drier installed?Then when should the suction drier be taken out?Should the acid neutralizer be added &/or an acid test? Is my new condensing unit now ruined? Thanks

By installing a suction line filter dryer it will adsorb the acid and be removed from the system. The maximum time the suction line filter dryer should remain in the system is 72 hours of run time.

By adding an acid neutralizer to a system in order for it to neutralize the acid a chemical reaction must take place and will ad other constituents to the refrigerant circuit. Not a good idea

[gravity]

a suction drier can stay in the system indefinitely. a pressure drop should be taken. if there is more then a 3psi difference, the dryer should be replaced.

were the copper lines replaced? you said the evap coil was replaced? how well did they flush the lines.

[second opinion]

a suction drier can stay in the system indefinitely. a pressure drop should be taken. if there is more then a 3psi difference, the dryer should be replaced.

were the copper lines replaced? you said the evap coil was replaced? how well did they flush the lines.

What are you basing your statement on?

[gravity]

facts and experience.

if a suction drier has no pressure difference across it then it can stay in the system.
if the drier has a 3 or more psi difference then its time to replace the drier.
the whole 72 hours is BS. a lot of techs dont know how to check them, so if manufacturers say no more then 72 hours then there may be a chance it might get replaced.

we use a lot of core driers.

[plea5ehelp]

What are you basing your statement on?

Hi,
I really appreciate all of the input. This has been/continues to be a learning experience for me.I knew nothing about the HVAC process and have just trusted the installer-but look where its got me!
Anyway, when the coil was replaced, as well as the several times the compressor was replaced, he assured me he flushed the lines and took every precaution.Obviously that cannot be right since there have been so many problems. That I know of no copper lines were replaced.
Is it too late to take precautions for the new condensing unit installed 2 months ago? Should I have him come out and re-check the system for acid? Should I insist that a suction line dryer be put on for 72 hours and then re-checked to see if that needs to be repeated? Just want to know where to go from here...
thanks

[second opinion]

facts and experience.

if a suction drier has no pressure difference across it then it can stay in the system.
if the drier has a 3 or more psi difference then its time to replace the drier.
the whole 72 hours is BS. a lot of techs dont know how to check them, so if manufacturers say no more then 72 hours then there may be a chance it might get replaced.

we use a lot of core driers.

You might want to check you facts. There is not a single compressor manufacturer or filter manufacturer that promotes or condones leaving an acid core dryer in a system when used as a clean up measure. As the concentration of acid is adsorbed inside the filter dryer it will deteriorate the retaining sieves inside allowing the filter to separate.

Now a suction line dryer that is installed in a new system can remain in the system indefinitely unless there is a pressure drop shown across it.

[second opinion]

Hi,
I really appreciate all of the input. This has been/continues to be a learning experience for me.I knew nothing about the HVAC process and have just trusted the installer-but look where its got me!
Anyway, when the coil was replaced, as well as the several times the compressor was replaced, he assured me he flushed the lines and took every precaution.Obviously that cannot be right since there have been so many problems. That I know of no copper lines were replaced.
Is it too late to take precautions for the new condensing unit installed 2 months ago? Should I have him come out and re-check the system for acid? Should I insist that a suction line dryer be put on for 72 hours and then re-checked to see if that needs to be repeated? Just want to know where to go from here...
thanks

Have them do an acid test on the refrigerant to determine if it is indeed acidic.

By removing the entire condenser and replacing it and the indoor coil you have removed the majority of the contaminants, and if the lines where flushed it is probably fine, but an acid test is the only way to verify. When they do the acid test ask them for performance data on the system; pressures, temperatures, voltage, line size and length etc.

[plea5ehelp]

Have them do an acid test on the refrigerant to determine if it is indeed acidic.

By removing the entire condenser and replacing it and the indoor coil you have removed the majority of the contaminants, and if the lines where flushed it is probably fine, but an acid test is the only way to verify. When they do the acid test ask them for performance data on the system; pressures, temperatures, voltage, line size and length etc.

Sounds like a plan. Of course, I have no idea how to interpret the data, or even the acid test. If the system tests acidic, do they then put on the suction drier? Does anything need to be done with the line drier he said he installed?
thanks

[carmon]

I must agree...... if there is no pressure drop dont worry about it. I rarely use a suction drier...... not sure why..... just dont like them

[mark beiser]

Should I insist that a suction line dryer be put on for 72 hours and then re-checked to see if that needs to be repeated?

Not for free.

[second opinion]

Sounds like a plan. Of course, I have no idea how to interpret the data, or even the acid test. If the system tests acidic, do they then put on the suction drier? Does anything need to be done with the line drier he said he installed?
thanks

If it is acidic then the suction line acid core dryer should be installed, acid level retested after after 24 hours of run time and if clean remove dryer, if not repeat.

Chances are good that it will be negative since every thing except the refrigerant lines has been removed. The service data can be posted here to help determine if there is another issue that was killing the compressors such as air flow, kinked or restricted refrigerant line etc.