Photo may vary slightly — verify by model number before ordering.LG KSSCB421A 42,000 BTU 4-Way Ceiling Cassette Single-Zone Heat Pump System, R32, 21.5 SEER2 (KNSCB421A + KUSXB421A)
In stock and ordered before 1pm ET, Mon–Fri? It ships the same day from our US warehouse.
Not sure it's the right unit? Send the model and serial — help@totalhvacparts.com or 302-219-4994.
Need more than 4? Ask about factory lead time — we'll give you a real date, not a guess.
Min. order: 1 unit · Weight: 312.4 lb · Truck Freight
Overview
LG KSSCB421A is the complete 42,000 BTU (3.5 Ton) R32 single-zone 4-way ceiling cassette mini split heat pump system from LG's 4-Way Ceiling Cassette line: the KNSCB421A indoor unit and the KUSXB421A inverter outdoor unit, sold together as the matched, AHRI-rated pair. It is rated 21.5 SEER2, 13.50 EER2, 10.8 HSPF2, runs on 208-230/60/1 power (32 A MCA / 40 A MOP), and is the direct R32 replacement for the R-410A LC429HV (LCN429HV + LUU420HV).
Capacity modulates across 16,800 / 42,000 / 49,000 Btu/h in cooling and 18,000 / 48,000 / 57,600 Btu/h in heating (min / rated / max), so the system idles at part load instead of cycling. Heating continues down to -13°F outdoor, with 50,700 Btu/h available at 17°F and 43,500 Btu/h at 5°F.
What's in the bundle
- 1 × LG KNSCB421A 42,000 BTU 3×3 ceiling cassette indoor unit with Wireless Remote Controller PWLSSB21H
- 1 × LG KUSXB421A R32 inverter heat pump outdoor unit
What you still need
- 3/8 Flare × 5/8 Flare line set, 16.4 / 246 ft
- Interconnect cable, disconnect and breaker sized to the MCA/MOP in the specifications; pad or wall bracket; condensate drain
- Requires PT-AAGW0 grille (sold separately)
Typical coverage is roughly 1,800–2,200 sq ft depending on climate, insulation and layout. AHRI reference 214837927 (Energy Star, Energy Star Cold Climate). Installation and warranty registration should be completed by a licensed contractor who has completed LG training; the LG limited warranty document is linked under Documentation.
What's Included
This system ships as the LG-matched pair below. Each component is also sold separately — see Companion Units further down.
- Includes KNSCB421A indoor unit
- Includes KUSXB421A outdoor unit
Specifications
Values in italic are not yet confirmed from OEM documentation. Ask us to verify before ordering.
Documentation
Companion Units & System Bundle
After You Order
Order number and confirmation by email the moment you check out.
Pulled from our shelf — the same live count you saw on this page. In-stock orders placed before 1pm ET, Mon–Fri, leave the same business day.
Tracking number lands in your inbox the moment it leaves the building.
Check the part number on the label against your order before installing. Wrong or damaged? Tell us — we'll sort it out.
Ask the Parts Desk
Not sure this fits? Need more than what's in stock? Send the model and serial from the unit's data plate — a real person reads it and confirms before you order.
Common Questions
What is included with the KSSCB421A system?
KSSCB421A ships as Includes KNSCB421A indoor unit and Includes KUSXB421A outdoor unit. Line set, interconnect wiring, disconnect, pad or bracket and condensate drain are field supplied.
What does the KSSCB421A replace?
KSSCB421A is LG's current R32 model in this position and replaces the discontinued LC429HV, LCN429HV + LUU420HV. R32 and R-410A equipment cannot be mixed — replace the indoor and outdoor unit together.
What power does the KSSCB421A need?
208-230V, 1-phase. Minimum circuit ampacity and maximum overcurrent protection are listed in the Specifications table above and on the LG submittal under Documentation; size the breaker and wire to those values and local code.
Is the submittal sheet and installation manual available for KSSCB421A?
Yes — the LG submittal data sheet, engineering manual, installation manual and warranty document are all linked under Documentation on this page and can be downloaded without an account.
Is the stock number on this page real?
Yes — it's the live count from our own shelf, not an availability estimate. If it says 4, that's how many are physically here. When it hits zero, this page says so.
Is this a genuine LG unit, or aftermarket?
Genuine LG OEM equipment — not an aftermarket substitute.
I see this listed under a different name on other sites. Is it the same part?
Yes — manufacturers and distributors sometimes use different brand names or legacy labels for the same part number. Part number KSSCB421A is identical across all name variations.
What's the warranty on this part?
Warranty terms vary by manufacturer. Contact us with your order number for details specific to this part.
How fast does this ship?
In-stock items ship the same business day on orders placed before 1pm ET, Monday–Friday. Standard ground delivers to most of the continental US in 2–5 business days. This part ships by LTL freight, so transit runs on the freight schedule — we'll contact you to arrange delivery.
Does everything ship UPS or FedEx Ground?
This part ships by truck freight rather than parcel — still free, included in the price shown, and we'll contact you to schedule delivery before it ships.Most orders ship UPS or FedEx Ground. A small number of large or heavy parts across the catalog ship by truck freight instead — that's still free, and we reach out to arrange a delivery window before those orders leave the warehouse.
