Description
The MRCOOL Signature Series MCAEAMPEF42C21AA is a 3.5-ton multi-position air handler for R-454B split systems, matched with Signature Series heat pump and air conditioner condensers for AHRI-rated performance. It installs upflow, downflow or horizontal to fit closets, attics and crawlspaces. An ECM blower motor moves air quietly, and an optional MRCOOL electric heat kit adds supplemental or emergency heat.
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.
Key Features
- Configuration: Multi-position (upflow, downflow, horizontal)
- Design: Slim, space-saving profile for attics, closets, or crawlspaces
- Cabinet: Durable galvanized steel construction
- Blower Motor: High-efficiency ECM
- Coil: Copper “A” coils with enhanced aluminum fins for superior heat transfer & humidity control
- Insulation: Internal thermal insulation reduces energy loss, condensation & noise
- Filter: Built-in filter rack for easy maintenance
Product Specifications
| Blower Motor | ECM, 3/4 HP |
|---|---|
| Rated Airflow | 1254 CFM |
| Minimum Circuit Ampacity | 7.2 A |
| Maximum Fuse / Breaker | 10 A |
| Refrigerant Connections | 3/8" liquid, 3/4" suction |
| Sound Level | 54 dB(A) |
| Unit Dimensions (W x H x D) | 19.6" x 45.75" x 22" |
| Unit Weight | 131 lb |
| Brand | MRCOOL |
| Model | MCAEAMPEF42C21AA |
| Series | Signature Series (R-454B) |
| Capacity | 42k (≈3.5 ton) |
| Refrigerant | R-454B (low-GWP, eco-friendly) |
| Configuration | Multi-position (upflow, downflow, horizontal) |
| Design | Slim, space-saving profile for attics, closets, or crawlspaces |
| Cabinet | Durable galvanized steel construction |
| Blower Motor | High-efficiency ECM |
| Coil | Copper “A” coils with enhanced aluminum fins for superior heat transfer & humidity control |
| Insulation | Internal thermal insulation reduces energy loss, condensation & noise |
| Filter | Built-in filter rack for easy maintenance |
| Heat Option | Optional electric heat kit for colder climates |
| Thermostat Compatibility | Works with most third-party thermostats (smart home ready) |
Compatibility & Installation
- Matched system: Pairs with Signature Series R-454B heat pump (MCAESHS4T) and air conditioner (MCAESAS4T) condensers of the same tonnage.
- Line set: Sweat (brazed) connections; line set not included.
- Professional installation: Must be installed by a licensed HVAC contractor; R-454B is an A2L refrigerant.
