MRCOOL Signature Series 42k BTU 3.5-Ton 13.4 SEER2 Packaged Air Conditioner

The MRCOOL Signature Series 3.5 Ton 42,000 BTU 14 SEER Packaged Air Conditioner is a self-contained packaged air conditioner that combines the compressor, condenser, and air handler into a single outdoor cabinet — eliminating the need for separate indoor and outdoor components. Designed for residential and light commercial cooling, this cooling-only unit runs on 208-230V single-phase power with R-410A refrigerant and supports both rooftop and ground-level installation through its multi-position duct design.

Key specifications

• Cooling capacity: 42,000 BTU nominal (40,000 BTU AHRI-rated); sized for spaces up to approximately 1,750–2,100 sq. ft.
• Efficiency: 14 SEER / 11.0 EER — AHRI Certified to Standard 210/240
• Power supply: 208-230V, single-phase, 60Hz; minimum circuit ampacity 27.5A; max 40A fuse/HACR breaker
• Refrigerant: R-410A (environmentally friendly) — copper tubing with enhanced fin coils; 108 oz. factory charge
• Certifications & warranty: ETL Listed (Intertek), AHRI Certified; 10-year limited parts and compressor warranty

One cabinet, no split-system complexity

Traditional split systems require a matched indoor air handler, refrigerant line sets run through walls or ceilings, and precise field charging — adding labor hours and potential leak points. This packaged unit arrives pre-charged and factory-assembled, so installation comes down to ductwork connections, a single electrical circuit, and a condensate drain. The insulated cabinet minimizes heat loss and keeps operating sound at a low 78 dBA, making it a practical fit for occupied residential and light commercial settings.

Key Applications

• Residential rooftop: Designed to mount on a roof curb (sold separately), making it a direct replacement for aging rooftop packaged air conditioning units on homes with flat or low-slope roofs.
• Ground-level pad install: The compact 47.66 × 47.66 in. footprint fits a standard equipment pad alongside structures that lack attic or basement mechanical space.
• Light commercial: Sized for small-to-medium offices, retail spaces, or workshops where a single self-contained unit handles the full cooling load without a dedicated mechanical room.
• Replacement unit: The included horizontal and downflow duct covers allow the unit to drop into existing packaged unit installations without modification to ductwork orientation.
• Manufactured and modular housing: Packaged units are a standard system type for manufactured homes with ductwork configured for a single-cabinet unit.

Built-in protection and serviceability

• Drain pan float switch monitors condensate level continuously and shuts the unit down if the drain line becomes clogged — preventing water damage before it starts.
• Constant torque blower motor maintains consistent 1,400 CFM airflow across a wide static pressure range; the slide-out blower housing allows full service access without major disassembly.
• One-piece "no leak" top and louvered coil guard protect refrigerant components from weather and physical damage in outdoor installations.
• Antimicrobial insulated drain pan and internal service gauge ports reduce maintenance time and support long-term system hygiene.

Electrical and duct requirements

This unit requires a dedicated 208-230V, single-phase, 60Hz circuit with a minimum circuit ampacity of 27.5A and a maximum 40A fuse/HACR breaker. Both horizontal and downflow duct configurations are supported — duct covers for both orientations ship with the unit. Utility connections are located on the right side of the cabinet, and optional kits enable bottom power entry through the base pan for clean below-roof installations. The unit weighs 460 lbs. and requires a matching roof curb for rooftop applications (sold separately). Optional electric heat kits — MHK05P (5kW), MHK07P (7.5kW), MHK10P (10kW), MHK15P (15kW), and MHK20P (20kW) — are compatible with this model and add resistance heating capability when required.

Why choose the MRCOOL Signature Series MPC421M414A-2?

The MRCOOL Signature Series MPC421M414A-2 is well-suited for buyers who need a straightforward, independently certified cooling solution without the installation complexity of a split system. Its AHRI Certification means the 14 SEER efficiency rating is third-party verified — not a manufacturer claim. The 10-year limited parts and compressor warranty reduces long-term ownership risk, and the multi-position design handles rooftop, ground-mount, horizontal, and downflow configurations from a single SKU, keeping the ordering and installation process simple.