3.5 Ton EcoTemp R-454B Multi-Positional Cased Coil, W5AM42M21XA
Crossing into 3.5 tons changes the plumbing: the W5AM42M21XA is the first coil in the EcoTemp R-454B line with a 7/8 in. suction connection, matched to a 21 in. wide, 29-3/4 in. tall cabinet and a 1050 to 1750 CFM airflow rating. It produces 58.7 MBH gross at 1400 CFM, and like every W5AM coil it arrives with a refrigerant-specific TXV already installed, both vertical and horizontal FRTP drain pans, factory UV knockouts, and the complete A2L leak dissipation system that R-454B installations require.
Is a 3.5 Ton Cased Coil the Right Size?
A 42,000 BTUH nominal coil typically lands under 3.5 ton condensers serving homes in the 1,800 to 2,400 sq. ft. range, or smaller homes with heavy glazing, high ceilings or a hot-climate design day. Capacity data is published at 1050, 1400 and 1750 CFM, so the coil covers a wide operating window — but the top of that window demands a blower that can actually deliver it against the coil, filter and duct static combined.
Two things separate this size from the 3 ton coils below it. The cabinet widens to 21 in., which means the furnace or blower underneath needs to be 21 in. or fitted with an offset adapter kit. And the suction line steps up to 7/8 in., so a straight reuse of an older 3/4 in. line set is not automatic — the line set has to be sized for the outdoor unit, not for convenience. Confirm the AHRI-certified match first, then work backward through duct, blower and line sizing.
Ideal for: 1,800 to 2,400 sq. ft. homes, 3.5 ton changeouts on 21 in. furnace cabinets, high-ceiling or heavily glazed spaces, and Sun Belt installations where design-day sensible load runs above what a 3 ton system will hold.
Need more capacity? Step up to the 4 Ton EcoTemp W5AM48M21XA Cased Coil, which adds a half ton in an identical 21 in. by 29-3/4 in. cabinet with the same 7/8 in. suction connection.
Recommended applications are general guidelines only. Actual coil selection depends on the AHRI-certified system match, blower capability, duct static, and local design conditions. Request free sizing assistance, contact Budget Heating, or call 813-885-7999.
What's Included
| Model Number | W5AM42M21XA — 3.5 Ton Multi-Poise Cased Evaporator Coil |
|---|---|
| Nominal Capacity | 3.5 Ton / 42,000 BTUH |
| Coil Type | Vertical A-Coil, Cased |
| Airflow Configuration | Multi-Poise — Upflow, Downflow, Horizontal-Left, Horizontal-Right |
| Refrigerant | R-454B Only |
| Cabinet Width | 21 in. |
| Cabinet Height | 29-3/4 in. |
| Suction Line Connection | 7/8 in. Sweat |
| Liquid Line Connection | 3/8 in. Sweat |
| Metering Device | Factory-Installed R-454B TXV |
| Rated Airflow Range | 1050 – 1750 CFM |
| Operating Weight | 72.3 lb |
| Leak Dissipation | Complete A2L Dissipation System Included |
| Warranty | 5-Year Parts Limited; 10-Year with Registration Within 90 Days |
Pair the coil with the 3.5 ton EcoTemp W5A5S42AKAWA condenser or the W5H5S42AKAAA heat pump. Because the suction connection moves to 7/8 in., order the line set to the outdoor unit's specification and add a liquid line filter drier. Other coils in this size class are on the 3.5 to 4 ton cased coil page.
Cabinet & Coil Features
W5AM42M21XA Cabinet & Construction
- 21 in. wide cabinet on the tall 29-3/4 in. body
- 23.4 in. depth consistent with the rest of the W5AM range
- 24-gauge pre-painted taupe metallic steel
- Foil-faced R-2.1 insulation lining the entire casing
- Two FRTP drain pans, one vertical and one horizontal
- Unsurpassed pan strength with engineered drainage slope
- Primary and secondary 3/4 in. FPT drain connections
- Factory UV knockouts for fast UV lamp installation
- 72.3 lb operating, 80.0 lb shipping weight
- Ships 30.5 in. high by 21.6 in. wide by 23.4 in. deep
W5AM42M21XA Coil, Metering & Installation
- 58.7 MBH gross at 1400 CFM, 67°F EWB, 45°F SST
- First size in the series with a 7/8 in. suction connection
- 3/8 in. liquid line connection with factory TXV screen
- Refrigerant-specific R-454B thermostatic expansion valve installed
- Sweat connections with straight tube for braze-less compression fittings
- Side tubing routing for coil cleaning and TXV serviceability
- Complete A2L dissipation system, sensor factory mounted
- 2100 psi minimum burst pressure — three to five times application pressure
- Split delta plate and tool-free front coil removal
- AHRI rated performance, UL and c-UL listed
Specifications & Manuals
Size 4221 data appears in the dimensional, capacity and static pressure drop tables. The installation instructions detail brazing procedure with a nitrogen purge, TXV bulb placement and insulation wrap, and the recommended condensate trap geometry.
Frequently Asked Questions
What suction line size does the W5AM42M21XA require?
7/8 in. suction with a 3/8 in. liquid line. This is the first W5AM size to move up from 3/4 in. suction, so verify the line set rather than assuming an older run will serve.
Will a 3.5 ton W5AM42M21XA fit a 21 in. air handler cabinet?
Yes, the casing is 21 in. wide. If the furnace or blower below is a different width, ICP coil adapter kits NAHB00101CA, NAHB00201CA and NAHB00301CA cover no-offset, single-offset and double-offset transitions.
What airflow can the 4221 coil handle?
1050 to 1750 CFM, with published capacity data at 1050, 1400 and 1750 CFM. Check the coil static pressure drop table before designing to 1750 CFM — the blower has to overcome coil, filter and duct losses together.
How does the 42-size compare with the 4 ton 48-size coil?
Identical cabinet: 21 in. wide, 29-3/4 in. tall, 7/8 in. suction. The 4821 adds a half ton of capacity, raises the airflow range to 1200–2000 CFM, and weighs about 5 lb more. Same footprint, more coil.
Is a liquid line filter drier recommended with this coil?
Yes. A liquid line filter drier should be installed on any changeout, and it is standard practice on new R-454B installations to protect the TXV from system debris and moisture.
What is the burst pressure rating of the coil?
The coil meets or exceeds 2100 psi burst pressure, which the manufacturer notes is at least three to five times the pressure it would see in actual application.
W5AM Technical Specifications
