My AC Guy Says I Need a New Line Set Because I’m Switching Refrigerants
Your AC guy says:
“The new system uses a different refrigerant, so we have to replace the refrigerant lines.”
Maybe.
But switching refrigerants does not automatically mean the copper has to be replaced.
The existing line set may be reusable.
Or it may not be.
We need to evaluate it.
The Refrigerant Changed. The Copper Didn’t.
Your line set is the copper piping connecting the indoor and outdoor equipment.
With the transition from systems using refrigerants such as R-410A to newer A2L refrigerants such as R-454B and R-32, it’s reasonable for homeowners to wonder whether all that existing copper now has to come out.
Not automatically.
What matters is whether the existing piping is approved and appropriate for the new equipment.
That means we need to consider things like:
- line sizes
- line length
- vertical lift
- physical condition
- previous leaks
- contamination
- manufacturer requirements
- installation requirements for the new system
The equipment installation instructions get a pretty important vote here.
What About Oil and Refrigerant Left in the Lines?
That’s part of properly preparing an existing line set for reuse.
We don’t simply disconnect the old equipment, leave whatever happens to be inside the copper, attach the new system and yell:
SEND IT.
The piping needs to be prepared according to the new equipment manufacturer’s instructions and applicable procedures.
Exactly what’s required depends on the old system and the new equipment.
And We Pressure Test It
If we’re going to connect a brand-new AC to an existing line set—especially one hidden underground or inside walls—we’d really like to know that the piping doesn’t leak.
So we pressure test.
If it holds and everything else about the line set is appropriate?
Great.
If it doesn’t?
Now we have a reason to repair, replace or reroute it.
What If the Lines Are Underground?
We’ve dealt with both outcomes.
We’ve had Palm Coast installations where existing underground refrigerant lines had no concerning leak history, were appropriate for the new equipment and could be tested before startup.
Reuse them.
We’ve also had installations where underground lines needed to be abandoned and new copper routed overhead through the attic.
Replace them.
The difference wasn’t:
“New refrigerant.”
The difference was the condition and requirements of the actual installation.
When Would We Replace the Line Set?
There are plenty of legitimate reasons:
- incorrect pipe sizes
- confirmed leak
- history of recurring line-set leaks
- physical damage
- contamination that can’t reasonably be addressed
- manufacturer requirements
- installation conditions that make reuse inappropriate
Those are reasons.
“R-454B can’t go through old copper”
by itself isn’t much of one.
What Should You Ask?
Ask:
“Does the manufacturer require new refrigerant lines for this equipment, or can my existing line set be reused if it meets the specifications and passes testing?”
That’s the question.
The Klein Answer
Changing refrigerants does not automatically mean changing every inch of copper in your house.
Sometimes the existing line set is perfectly usable.
Sometimes it isn’t.
Check the new equipment requirements.
Check the sizing.
Check the condition.
Prepare it properly.
Pressure test it.
Then decide.
It’s the same basic philosophy we use with underground lines:
You don’t repipe your house because you bought a new water heater.
And we don’t tear perfectly good copper out of your house simply because the sticker on the new condenser lists a different refrigerant.