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Singnature Series
MRCOOL Signature Series 3.5 Ton Multi-Position Air Handler | MCAEAMPEF42C21AA
$1,321.69
In StockShips in 1-2 business days
High efficiency. Quiet performance. Easy installation.
A smart, reliable choice for year-round comfort.
Best for:
- Bedrooms
- Home Offices
- Additions
- Garages
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- Cooling
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- Heating
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- Quiet Inside
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- High Efficiency
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Brand Information
MrCool
- Support Number
- (270)366-0457
- Official Site
- MrCool Official Site
Product Overview Full product description Read the longer product copy, features, and application notes. +
MRCOOL — Air Handlers
MRCOOL Signature Series 3.5 Ton Multi-Position Air Handler | MCAEAMPEF42C21AA
MRCOOL Signature Series 3.5 Ton Multi-Position Air Handler | MCAEAMPEF42C21AA
Summary
The MRCOOL® Signature Series 42k Multi-Position Air Handler is built to provide consistent, energy-efficient comfort in any climate. Designed for flexibility and performance, this unit works with R-454B refrigerant, a low-GWP alternative that helps reduce environmental impact without sacrificing power or reliability. Its multi-position design allows for installation in upflow, downflow, or horizontal configurations, making it ideal for a variety of home layouts, from new construction to tight retrofits. With its slim, space-saving profile, it fits easily into closets, attics, or crawl spaces while still delivering full-capacity heating and cooling when paired with a compatible condenser or heat pump. Engineered for durability, the air handler includes a galvanized steel cabinet, a high-efficiency ECM blower motor, and copper "A" coils with enhanced aluminum fins for superior heat transfer and humidity control. Thermal insulation inside the cabinet reduces energy loss and prevents condensation, contributing to quiet operation and lower energy bills. Installation is fast and simple, helping to minimize labor time and disruption. An air filter rack allows for easy maintenance, while an optional electric heat kit is available for added heating performance in colder regions. Smart home compatibility comes standard, with support for most third-party thermostats so you can manage comfort on your terms; no proprietary systems required. Protected by a 10-year limited parts warranty, the MRCOOL® Signature Series 42k Multi-Position Air Handler offers long-lasting performance, space-saving design, and year-round efficiency for today's comfort-conscious homeowner.
Important
AHRI certified- meets industry standards.Register your productto activate warranty coverage.This air handler contains R-454B refrigerant, which is classified as an A2L refrigerant. To comply with safety standards, this unit must be paired with an R-454B condenser equipped with a leakage detection system. Failure to comply with these requirements may result in safety hazards and could void the warranty.
Key Features
- 42,000 BTU capacity (3.5 Ton)
- Multi-position installation (upflow, downflow, horizontal)
- Low-GWP R-454B refrigerant
- High-efficiency ECM blower motor
- Quiet operation (54 dBA)
- Durable galvanized steel cabinet
- Copper "A" coils with enhanced aluminum fins
- Built-in air filter rack for easy maintenance
- Compatible with most third-party thermostats
- Optional electric heat kit available
- Internal thermal insulation
- AHRI certified
- 5-speed blower motor for precise airflow control
Complete Technical Specifications
| Brand | MRCOOL |
| Series | Signature Series Multi-Position Air Handler |
| Model | MCAEAMPEF42C21AA |
| UPC | 840255595889 |
| GTIN | 00840255595889 |
| Unit Type | Air Handler |
| Configuration | Multi-Position |
| Certifications | UL Listed, CSA Listed, ETL Listed, AHRI Certified |
| Capacity | 42,000 BTU (3.5 Ton) |
| CFM | 1254 |
| Refrigerant | R-454B |
| Electrical | 208/230V 1 Phase 60 Hz |
| Min Circuit Ampacity | 7.2A |
| Max Fuse Breaker | 10A |
| Blower Motor Type | ECM |
| Blower Motor HP | 3/4 |
| Blower Motor Speeds | 5 |
| Blower Motor RPM | 1040 |
| Sound Rating | 54 dBA |
| Liquid Line Size | 3/8" |
| Suction Line Size | 3/4" |
| Drain Connection Size | 3/4" |
| Filter Type | Replaceable |
| Filter Size | 18" x 21" x 1" |
| Metering Device | Orifice |
| Auxiliary Heater Included | No |
| Auxiliary Heater Available | Yes (5kW, 7.5kW, 10kW) |
| Net Dimensions (HxWxD) | 45.75" x 19.625" x 22" |
| Net Weight | 131 lbs |
| Shipping Dimensions | 47.875" x 22.83" x 25.6" |
| Shipping Weight | 144 lbs |
Performance Features
| Compatible Equipment | Signature Series Top Discharge Condensers |
| Installation Flexibility | Multi-position (upflow, downflow, horizontal) |
| Refrigerant | Low-GWP R-454B refrigerant for reduced environmental impact |
| Motor Technology | High-efficiency ECM blower motor |
| Noise Reduction | Quiet operation (54 dBA) |
| Coil Technology | Copper "A" coils with enhanced aluminum fins |
| Cabinet Construction | Durable galvanized steel |
| Speed Control | 5-speed motor for precise airflow adjustment |
| Airflow Capacity | High-capacity 1254 CFM for maximum performance |
| Smart Home Compatibility | Works with most third-party thermostats |
| Heating Options | Optional electric heat kits (5kW, 7.5kW, 10kW) |
Warranty Information
- Registered Warranty: 10 years parts, limited compressor
- Base Warranty: 10 years parts, limited compressor
- Registration may be required for full warranty coverage
Manuals & Certifications
Safety Information
PROPOSITION 65 WARNING: This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.
Advanced Technology
The MRCOOL Signature Series 42k Multi-Position Air Handler features advanced ECM motor technology with a powerful 3/4 HP motor that delivers superior energy efficiency and precise airflow control across five speed settings. The copper "A" coils with enhanced aluminum fins provide exceptional heat transfer and humidity control for optimal indoor comfort in larger residential and light commercial applications. The durable galvanized steel cabinet ensures long-lasting performance, while comprehensive thermal insulation minimizes energy loss and prevents condensation. Operating at just 54 decibels, this 3.5-ton air handler maintains remarkably quiet performance despite its substantial 1254 CFM airflow capacity. The ECM motor's intelligent operation automatically adjusts airflow to maintain optimal system performance, while compatibility with most third-party thermostats enables seamless integration into modern smart home ecosystems for complete comfort control.
Installation Advantages
This 3.5-ton air handler provides exceptional installation versatility with true multi-position capability for upflow, downflow, or horizontal configurations, making it ideal for space-constrained installations in attics, closets, and crawlspaces. The high-efficiency ECM motor delivers superior performance with lower energy consumption while handling the substantial 1254 CFM airflow requirement for larger homes. The built-in air filter rack simplifies routine maintenance with easy access for quick filter replacements. The unit's streamlined design minimizes installation time and labor costs, while multiple optional electric heat kit sizes (5kW, 7.5kW, or 10kW) provide flexible heating capacity for various climate requirements. With its compact footprint and comprehensive compatibility with Signature Series Top Discharge Condensers, this air handler represents a premium, energy-efficient solution for residential and light commercial HVAC systems requiring robust performance in demanding applications and larger spaces.
Specs & Documents Product details Open technical specs, manuals, videos, and product documents. +
Product FAQs
Product FAQs
Helpful answers matched to this product, brand, specs, and configuration.Where should I purchase MRCOOL equipment?
MRCOOL products are sold through authorized retailers and distributors rather than directly by MRCOOL to consumers. Purchasing through an authorized seller helps confirm that the equipment is genuine and that the correct purchase records are available for product and warranty support.
Can MRCOOL components from different series, generations, or refrigerant platforms be mixed?
Do not assume that MRCOOL indoor units, outdoor units, line sets, controls, or accessories are interchangeable. Use only manufacturer-approved combinations for the exact model family; in particular, MRCOOL states that R-410A products are not compatible with R-454B products and the refrigerants must never be mixed.
What makes an eligible MRCOOL DIY system different from a conventional mini-split?
Eligible MRCOOL DIY systems are designed around installation-friendly components such as factory-precharged line sets and compatible connection hardware. The included components vary by generation and package, and electrical work, permits, clearances, and local code requirements still need to be followed.
Does MRCOOL send technicians to a home or jobsite?
MRCOOL does not dispatch field technicians. Its in-house team provides phone and email assistance for diagnosis, troubleshooting, and product guidance, while the owner arranges and pays for any local on-site technician unless a specific written warranty program states otherwise.
Why do I need the exact MRCOOL model and serial number?
The model and serial number identify the exact equipment, generation, capacity, and applicable documentation or warranty. Use the identification labels on the equipment and MRCOOL’s registration guidance rather than relying only on a product title or general series name.
Are all MRCOOL systems designed for do-it-yourself installation?
No. Only product families specifically identified by MRCOOL as DIY-capable should be treated as do-it-yourself systems. Other lines, including the Advantage Series, require professional HVAC installation, so always follow the installation requirements for the exact model.
Where can I find MRCOOL manuals, specifications, certifications, and installation documents?
MRCOOL maintains a documentation library and a product support center with model-specific installation manuals, owner manuals, technical documents, certifications, warranty information, and troubleshooting resources. Search using the exact model number because documents can differ by series, generation, capacity, and refrigerant.
What types of products does MRCOOL offer?
MRCOOL offers a broad range of comfort products, including ductless mini-splits, central ducted split systems, packaged heat pumps, geothermal systems, water heaters, fans, thermostats, line sets, and HVAC accessories. Available capacities, refrigerants, efficiencies, and features depend on the exact product family and model.
When should an MRCOOL system be registered?
Register the system as soon as possible after purchase and installation. Several MRCOOL residential warranty programs require registration within 60 days of installation, or within 60 days of purchase when the installation date cannot be verified, but the exact requirement is controlled by the warranty document for the specific product.
Where can I purchase replacement parts for an MRCOOL system?
MRCOOL recommends starting with the original place of purchase because many dealers can special-order replacement parts. If that is not available, use an authorized MRCOOL parts distributor and confirm compatibility with the exact model and serial number before ordering.
How can I contact MRCOOL customer or technical support?
MRCOOL provides support by phone at (270) 366-0457, by email at support@mrcool.com, and through its online support-request form. Have the exact model and serial number available so the support team can identify the correct product documentation and next steps.
Can MRCOOL support work with my local HVAC technician?
Yes. If a local technician is scheduled, MRCOOL’s in-house support team can help coordinate troubleshooting and product guidance with that technician. The technician should have the model, serial number, system configuration, measurements, error codes, and a clear description of the issue available.
Where can I find MRCOOL troubleshooting and error-code information?
MRCOOL’s support center provides separate technical-support sections for ductless systems, residential ducted systems, product-specific error codes, wiring guidance, installation procedures, and troubleshooting articles. Use the exact series and model because codes and procedures are not universal across all MRCOOL equipment.
How do I register an MRCOOL product for warranty coverage?
Register the product through MRCOOL’s online warranty-registration page. Be prepared to provide the serial number along with purchase, owner, installation-location, and installer information requested by the registration form.
Does every MRCOOL product have the same warranty?
No. MRCOOL publishes separate warranty terms for different product families, generations, and applications. For example, the current DIY 5th Generation warranty lists 5-year parts and 7-year compressor coverage, but that coverage should not be assumed for another MRCOOL series; always check the exact product warranty document.