The 4-Ton R-32 Sweep Bend — Tony’s Rule for Getting Suction Lines Arou

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By Tony — because R-32 punishes bad bends faster than any refrigerant you’ve ever worked with.

🌀 1. Introduction — Why R-32 Changes Everything About Line-Set Bending

If you’ve ever installed a 4-ton AC system using R-410A, you probably think you know how copper behaves:

Bend it gently
Don’t kink it
Keep the radius reasonable
Insulate the suction line
Brazing fixes most sins

But here’s the truth:

Everything you learned bending copper for 410A becomes twice as important — and twice as unforgiving — with R-32.

R-32 is:

Higher pressure
Higher heat transfer per pound
More turbulence-sensitive
More friction-loss sensitive
More reactive to sharp angles
More dependent on smooth suction-line airflow

When homeowners call me because their new R-32 4-ton Goodman isn’t cooling right, 80% of the time I already know the culprit:

A suction line bent like an elbowed garden hose.

R-32 doesn’t tolerate sharp turns, crushed copper, or kinked tubing the way 410A sometimes did.

That’s why I follow one golden rule:

On R-32 systems, every bend is a sweep bend — or you’re losing capacity.

Today I’ll show you exactly why that rule exists, how tight corners steal tonnage, and how to bend the suction line around an impossible corner without sacrificing performance.

4 Ton 14.5 SEER2 120,000 BTU 80% AFUE Goodman Upflow Air Conditioner System with Models GLXS4BA4810, CAPTA6030D3, GR9S801205DN

🔍 2. The Science: Why Tight Bends Kill R-32 Efficiency

Let’s break down the physics.
R-32 is a high-pressure, high-velocity refrigerant.
That means:

✔️ Pressure drop matters more

Every sharp bend creates friction and local turbulence.

✔️ Velocity spikes at the inner radius

This causes micro-eddies where refrigerant twirls, stalls, or recirculates.

✔️ Turbulence = heat transfer loss

The suction line’s entire job is to retain cooling.
Turbulence dumps BTUs right back into the refrigerant.

✔️ Sharp bends flatten the tube

Flattening = reduced internal cross-section = reduced mass flow.

Mass flow is EVERYTHING for a 4-ton system.

If you take away internal volume by flattening or kinking copper, your 4-ton system might be operating like:

3.6 tons
3.2 tons
Sometimes even 2.5 tons under load

And you’ll never know unless you look at:

Suction saturation
Superheat
Temperature split
Compressor amp draw
Coil frost pattern

That’s why manufacturers (Goodman included) are obsessed with proper bend radius on R-32 systems.

🔧 3. Tony’s Rule #1: Minimum Radius = 6x the Tubing Diameter

This rule saves systems.

For a 4-ton Goodman R-32 system, the suction line is typically 7/8" OD.

Tony’s Minimum Bend Radius Formula

Radius = 6 × tubing diameter
6 × 7/8" = 5.25" minimum radius

Most installers use a radius of:

2"
3"
Whatever their hand torque provides
Whatever their bender allows

But if your radius is less than 5 inches, the internal flow becomes a heat-transfer disaster.

Why 6× matters

It guarantees:

No flattening of the copper
No airflow choke points
Minimal turbulence
Predictable superheat
Maximum capacity retention

This is the difference between:

🔥 A 4-ton system delivering 4 tons,
and
🥶 A 4-ton system cooling like a 3-ton.

🧰 4. Tony’s Tools for R-32 Sweep Bends

You cannot make proper R-32 bends with:

Your knee
Your foot
Your hands
A cheap bending spring
A plastic hardware-store bender

These methods will flatten the copper at the bend — guaranteed.

Tools Tony Actually Uses

✔️ Lever-style tubing bender (high leverage, long arms)

Allows smooth, constant-radius sweeps.

✔️ Ratchet-style tubing bender

Good for tight mechanical rooms with limited space.

✔️ Forming springs (only for micro-adjustments)

NOT for major bends — just to guide copper so it doesn’t collapse.

✔️ Pipe mandrel + helper

For big sweeping 6"+ radiuses where tools are awkward.

✔️ 90° pre-formed long-sweep elbows

When bending is impossible, brazed long-sweep fittings are 100× better than tight hand-bends.

Fitting Rule

A long-sweep 90 is better than a deformed bend.
A deformed bend is worse than anything.

🧊 5. How Tight Bends Destroy Cooling Capacity — Real Numbers

Let me give you the numbers homeowners never see.

Scenario A — Proper Sweep Bend

Radius = 5.5"
Pressure drop = negligible
Capacity delivered = ~100%

Scenario B — Mildly Tight Bend

Radius = 3"
Pressure drop = 5–7%
Capacity delivered = ~93–95%

Scenario C — Hand-bend kinked to 2" radius

Pressure drop = 10–20%
Capacity delivered = ~80–90%

Scenario D — Crushed or partially flattened

Pressure drop = 25–40%
Capacity delivered = ~60–75%
Compressor amp draw skyrockets.
Suction temperature drops.
Coil starts frosting.
Discharge temperature spikes.

This is why 4-ton R-32 systems often get blamed for cooling poorly.

It’s not the refrigerant.
It’s the copper.

🧭 6. Tony’s Rule #2: Bend BEFORE You Insulate

Most rookies:

Tape the suction line
Add insulation
Zip-tie it
Then try to bend it

This creates:

Flat spots
Micro-kinks
Split insulation
Internal turbulence
Noise under load

You ALWAYS bend copper bare, before insulation is added.

After bending:

Check for roundness
Inspect for micro-creases
Confirm radius
Only then insulate

🏗️ 7. How Tony Gets a 7/8" Suction Line Around a Tight Corner (Step-By-Step)

Here’s the exact method I use on 4-ton R-32 installs in small basements, attics, and closets.

Step 1 — Pre-map the route

Do NOT start bending until the route is:

Visualized
Marked
Measured

Step 2 — Mark bend points on the copper

Use a Sharpie and indicate:

Start of bend
Middle of bend
End of bend

Step 3 — Pre-heat the area (optional)

A tiny bit of heat makes copper more compliant.
(Not glowing. Just warm.)

Step 4 — Use a 6× radius bender

Begin your bend slowly and evenly.

Step 5 — Keep constant pressure

Never jerk the lever.
Smooth increments = smooth radius.

Step 6 — Check for roundness at every 15° turn

If the tube deforms:

Stop immediately
Re-round with mandrel or forming spring
Restart

Step 7 — Anchor the bend every 12–16 inches

Unanchored bends vibrate under load.
R-32 compressors start/stop more aggressively.

Step 8 — Insulate AFTER confirming radius

Use thick insulation and full-coverage tape.

🧪 8. Testing for Bend Failure — Tony’s 3 Diagnostic Checks

After installation, I ALWAYS check:

✔️ 1. Suction Line Temperature at the Coil

If suction line temp is dropping below expected superheat values, you may have:

Pressure loss
Excess turbulence
A partially collapsed bend

✔️ 2. Coil Frost Pattern

Uneven frost = suction obstruction.

✔️ 3. Superheat and Subcool Stability

If readings “hunt” or fluctuate:
You likely have a bend restricting flow.

📘 9. Verified Technical Resources (6 Max)

Here are reputable, verified external resources supporting coil installation, condensate management, and TXV behavior:

ASHRAE Fundamentals – Coil Construction & Airflow (Technical)
https://www.ashrae.org/technical-resources/ashrae-handbook
HVAC Drainage Code Requirements (ICC)
https://codes.iccsafe.org/
EPA HVAC Moisture & Condensate Guidelines
https://www.epa.gov/mold
AHRI Air Coil Performance Standards
https://www.ahrinet.org/standards
RSES TXV Installation & Superheat Guidelines
https://www.rses.org
Goodman (Daikin) Coil & TXV Transition Resources
https://www.daikincomfort.com/
ACCA Manual D — Duct & Line-Set Routing Principles
https://www.acca.org/standards/technical-manuals
ISO 14903 — Refrigeration and Air-Conditioning Piping Integrity Standard
https://www.iso.org