An LG indoor-outdoor split air conditioner set shown on a white background, including a ceiling-mounted indoor unit, outdoor condenser unit, and a handheld remote control.

LG 42,000 BTU Mini Split System - Multi Position AHU LGRED°, R32 | KSSLA421A

LG System Model: KSSLA421A AHRI-matched outdoor + indoor pair

✅Stock Status: In Stock: 4 complete systems — ships from our warehouse

54 in stock

Regular price $7,739.98
/
Shipping & Delivery
  • Free nationwide shipping — no freight surcharges at checkout.
  • Scheduled delivery included — LTL freight and single-system orders are delivered on a scheduled window coordinated with you or your site contact.
  • At delivery: inspect before signing and note any damage or shortage on the BOL/delivery receipt — it keeps a freight claim quick and clean.
LG experts standing by — for contractors & commercial operators
Model matching, application and electrical questions, availability, submittal support. This is a trade desk, not a homeowner hotline.
Call the LG desk 610-860-5220
Outfitting a project or buying 5+ systems?
Volume pricing on multi-unit orders · Net terms for qualified contractors · Tax-exempt purchasing
Request a Project Quote →
  • Complete factory-matched ducted system — KUSXA421A condenser + KNSLB421A multi-position air handler in one SKU
  • 19 SEER2 / 12.5 EER2 / 9.8 HSPF2
  • One 208-230V 1Ø circuit — 32 A MCA / 40 A MOP
  • Factory-charged R32, pre-charged for line sets to 24.6 ft
  • Heating rated down to -13°F outdoor ambient
  • 10-year parts & compressor limited warranty with LG registration
Full specifications, documents & submittals below ↓
30-day returns
  • 10% restocking fee when refunded as store credit
  • 25% restocking fee when refunded to your original payment
  • Free even exchange if you need a different part for your model
  • Wrong item shipped or defective on arrival? Full refund, no fee — we pay return shipping
Full return policy

KSSLA421A is LG's officially matched 42,000 BTU (3.5-ton) single-zone system — a Multi Position AHU LGRED° multi-position air handler paired with its matching outdoor condenser, exactly as LG designed it.

  • Outdoor unit: KUSXA421A
  • Indoor unit: KNSLB421A
  • LG System Model: KSSLA421A
  • R32 refrigerant, factory-matched capacity

This Multi-Position air handler installs upflow, downflow, or horizontal and connects to standard ductwork rather than mounting on a wall, and pairs with a wired LG wall controller (no included infrared remote). Rated heating operation down to -13°F outdoor ambient.

Effective July 15, 2026. Applies to orders placed on or after that date.

We know a return usually means a job didn't go as planned, so we've made the rules simple and put them right on every product page — no surprises. You have 30 days from delivery to start a return, and you always keep more of your money when you choose store credit.

Restocking fees at a glance

Item type Refund as store credit Refund to original payment
Standard items 10% restocking fee 25% restocking fee
Niche items (marked on the product page — what's a niche item?) 20% restocking fee Up to 50% restocking fee
Our mistake — wrong item shipped, defective on arrival, or damaged in shipping Full refund, no fee. We pay the return shipping.

Free exchanges for the wrong part

Ordered a board or part that doesn't fit your model? Exchange it for the correct one with no restocking fee — an even swap. If the correct part costs more or less, we'll charge or credit the difference. Not sure which part you need before you order? Use the model number search on the product page or contact us and we'll confirm compatibility.

Electrical components

Circuit boards, control boards, thermostats, sensors, inverters, and other electrical components can only be returned unopened, in factory-sealed packaging. Once an electrical part has been opened or installed, it cannot be resold and is not returnable. Defective electrical parts are covered by the manufacturer's warranty — contact us and we'll help you file the claim.

What are niche items?

Niche items are parts for less common systems and applications. They're marked on the product page, and they're just as ready to order as anything else we sell — the difference only shows up on the return side. Because these parts serve a much smaller market, a returned one (even unopened, in perfect condition) can sit a long time before the next contractor needs it. That added cost of restocking and reselling is why returns on niche items carry a higher restocking fee.

The best way to avoid the fee entirely: if you're not 100% sure the part fits your application, reach out before ordering — we'll confirm compatibility for free.

Condition requirements

  • Items must be uninstalled, unused, and in their original packaging with all hardware, manuals, and accessories. Our parts are commercial and industrial grade products intended for installation by licensed HVAC professionals.
  • Items returned damaged, incomplete, showing installation marks (tool marks, indentations), or with writing on the part or packaging may receive a reduced refund or be returned to you. Returned items must be resellable as new.
  • Return shipping is the customer's responsibility unless the return is due to our error. We'll provide the return address with your RMA — some returns go to our warehouses and some directly to the manufacturer.

Defective on arrival

Notify us of any defective product within 7 calendar days of delivery (based on tracking). Do not attempt to install a part you believe is defective — keep it in new, unused condition and contact us first so we can walk you through next steps. Some manufacturers require a tech support call or a diagnosis by a licensed professional before authorizing a defect claim; we'll let you know if that applies and handle the paperwork with you.

Damaged freight (LTL) deliveries

Inspect all freight shipments before signing the delivery receipt — it's your right to take a few minutes with the driver present. If you see damage, note it on the Bill of Lading (or refuse the delivery for significant damage) and notify us within 24 hours with photos. For concealed or hidden damage discovered after the driver has left, notify us within 5 days of delivery. We'll make it right at no cost to you.

Manufacturer warranties

We honor all manufacturer warranties applicable to parts sold on our website. Each manufacturer has a different warranty process, but we're experienced with all of them and will make sure you're taken care of.

Cancellations

  • Orders placed before 2–4 PM (ET) are processed 15 minutes after they are placed and released to our warehouses the same business day. All other orders are released immediately the next business day. Once an order has been processed and released, it can no longer be cancelled.
  • If you need to cancel and you are within this window, email us immediately at parts@rapidhvacparts.com with your order number. Until you receive email confirmation of the cancellation, expect the product to arrive.
  • Orders cancelled before processing receive a full refund with no fee.

How to start a return

  1. Contact us at returns@rapidhvacparts.com or through live chat with your order number.
  2. We'll confirm your item's return tier, quote your refund amount in dollars for both options (store credit and original payment), and send a Return Merchandise Authorization (RMA) with shipping instructions. Returns sent without an RMA cannot be processed.
  3. Once we receive and inspect the item, your refund or store credit is issued within 5 business days.

Store credit never expires and can be used on any future order.

International orders

Orders shipped outside the United States may not include all applicable taxes, duties, and fees — you may be responsible for these at delivery. Items sent to a freight forwarding service may surrender return protections, as some manufacturers will not be held liable once another entity handles their items.

  1. Confirmation email: You'll immediately get an email confirming your order shortly.
  2. Invoice: You'll get an email with a copy of your invoice as soon as your order is processed by our team.
  3. Fast shipping: Most parts ship the same day, reaching you in 1-2 business days (nationwide & free!). Make sure to look at your specific parts language for shipping information as some items will take longer.
  4. Tracking updates: We'll send tracking info so you can follow your package's journey.

Need help? Just contact us!

At any time, you can log in to your account on our site and see the progress as well or use our chat feature. 

Have questions/concerns or just need a status update?  Call 610-860-5220 or email parts@rapidhvacparts.com.

In stock — 4 complete systems in our warehouse, ready to ship
Cooling / Heating42,000 / 46,000 Btu/h
SEER2 / EER2 / HSPF219 / 12.5 / 9.8
Power Supply208-230V · 1Ø · 60Hz
MCA / MOP32 A / 40 A
RefrigerantR32 · 106 oz factory charge, pre-charged to 24.6 ft
AirflowIndoor blower: up to 1,225 CFM

What’s in the KSSLA421A System

Outdoor Unit — Condenser
KUSXA421A

LG Single Zone Inverter Heat Pump Condenser, LGRED°, R32

  • Variable-speed inverter compressor with EEV refrigerant control
  • Sound pressure: 56 dBA outdoor
  • Operating range: 5°F to 118°F cooling · -13°F to 64°F heating
  • 54-17/48" × 37-19/48" × 13" (net weight not published)
  • Pre-charged for line sets up to 24.6 ft — no added refrigerant required
View individual component listing →
Indoor Unit — Multi-Position Ducted Air Handler
KNSLB421A

LG Multi-Position Ducted Air Handler, R32

  • Upflow, downflow, or horizontal installation orientations
  • Variable-speed blower, connects to standard ductwork
  • Pairs with a wired LG wall controller (no included infrared remote)
View individual component listing →

KSSLA421A Features

Factory-Matched System

KSSLA421A is LG's official system model number for this exact condenser/air-handler pairing — the combination LG rates and warrants. One SKU, no compatibility guesswork.

Inverter Compressor

Variable-speed operation modulates capacity to match load instead of cycling on/off — tighter setpoint control, quieter operation, and lower operating cost.

R32 Refrigerant

Ships factory-charged with R32, compliant with the 2025 AIM Act refrigerant transition. Pre-charged for line sets to 24.6 ft; add charge per LG spec on longer runs.

Low-Ambient Heating

Rated heating operation down to -13°F outdoor ambient — LGRED°'s extended low-temperature performance. Consult the LG engineering manual for capacity retention curves when specifying as primary heat.

Ducted, Multi-Position Air Handler

Installs upflow, downflow, or horizontal — connects to standard ductwork rather than mounting on a wall, and pairs with a wired LG wall controller (no included infrared remote).

EEV Refrigerant Control

Electronic expansion valve meters refrigerant precisely across the full modulation range for stable superheat control at part load.

KSSLA421A Specifications

Performance
Rated Cooling Capacity42,000 Btu/h
Rated Heating Capacity46,000 Btu/h
SEER219
EER212.5
HSPF29.8
Electrical
Power Supply208-230V / 60Hz / 1Ø
Min. Circuit Ampacity32 A
Max Overcurrent Protection40 A
Refrigerant & Piping
RefrigerantR32
Factory Charge106 oz
Liquid Line3/8" O.D.
Vapor Line5/8" O.D.
Pre-Charged Length (no added charge)24.6 ft
Refrigerant ControlEEV (Electronic Expansion Valve)
Sound & Airflow
Outdoor Sound56 dBA
Indoor Sound41 dBA
Indoor Airflow, Max1,225 CFM
Dimensions & Weight
Outdoor Unit (W × D × H)54-17/48" × 37-19/48" × 13"
Indoor Unit (W × D × H)21" × 21-3/8" × 55-3/16"
Indoor Unit Weight (Net)160 lb
Operating Range
Cooling (Outdoor Ambient)5°F – 118°F
Heating (Outdoor Ambient)-13°F – 64°F
Electric Heat Kit
Available Kits3–20 kW (field-installed)
Certification
LG System ModelKSSLA421A

Documents & Submittals

Warranty

10-year compressor / 10-year parts limited warranty when the system is registered with LG after installation.
Unregistered systems carry LG's base coverage (5-year parts / 7-year compressor).
Warranty applies to matched-system installations by a licensed HVAC contractor — register at lghvac.com and retain proof of purchase.

Specifications are drawn from LG submittal data. Always verify against the current LG submittal sheet before final equipment selection.