This is the outdoor condenser unit for a Carrier Infinity 25 multi-zone ductless heat pump system — it is not a complete system by itself. It's built for homeowners who plan to run up to five indoor heads (wall, cassette, ducted, or floor/ceiling) off one outdoor unit, sold and installed by a licensed HVAC contractor.
Note: If you would like to review the manufacturer Product Specifications, Warranty, Brochure, etc., for this system, please refer to the "Resources (System Manuals and Warranty)" Tab above on this page.
The 37MGHAQ18CA3 is the 18K outdoor condenser in Carrier's Infinity 25 multi-zone lineup, built to pair with AHRI-matched indoor heads (wall mount, slim one-way cassette, 4-way cassette, concealed duct, or floor/ceiling) across up to five zones. It uses a variable-speed inverter compressor and Puron Advance (R-454B) refrigerant. Sound pressure and capacity figures below reflect the 18K column specifically, not the family "up to" maximums shown elsewhere in Carrier's literature. Note: If you would like to review the manufacturer Product Specifications, Warranty, Brochure, etc., for this system, please refer to the "Resources (System Manuals and Warranty)" Tab above on this page.
System Components
- Outdoor condenser unit: Carrier 37MGHAQ18CA3, family 37MGHA, 18K size, variable-speed compressor, R-454B refrigerant — included in this listing.
- Indoor unit(s): sold separately. Choose from Carrier's AHRI-matched indoor head lineup (wall mount, cassette, ducted, or floor/ceiling) rated for the 18K outdoor capacity — not included in this listing.
Installation Requirements & Accessories
- Voltage: 208/230V; 1 Phase; 60Hz.
- Refrigerant: R-454B (A2L, mildly flammable) — professional installation required.
- Standard piping length per indoor unit: 24.6 ft (7.5 m). Minimum: 10 ft (3 m). Maximum with no additional charge: 73.8 ft (22.5 m) per indoor unit. Total maximum system piping length: 196.9 ft (60 m).
- Line set is sold separately — not included with this outdoor unit.
- Both refrigerant lines must be insulated separately per the manufacturer installation documentation.
- Not compatible with 115V-only circuits.
- Not a listed match for indoor units outside Carrier's AHRI-certified 37MGHA-family combinations.
- Wall sleeve, mounting bracket, and indoor unit(s) are NOT included with this outdoor condenser listing.
Pro-Installer Tip
R-454B systems are unforgiving of sloppy flare connections — a flare nut torqued by feel instead of spec is the single most common cause of a slow refrigerant leak that shows up months later as an "E" communication fault or a no-cool callback. Vacuum the line set down properly before charging, and torque every flare joint with a calibrated digital torque wrench rather than a standard wrench — don't estimate the pull. This isn't optional paperwork: EPA Section 608 certification is required to handle R-454B refrigerant, and proper evacuation directly protects the system's rated SEER2/HSPF2 efficiency numbers over the life of the equipment.
Key Benefits
- Variable-speed inverter compressor delivers steady, low-fluctuation comfort rather than on/off cycling.
- Outdoor sound pressure as low as 61.5 dB(A) at the 18K size.
- Rated heating capacity of 19,000 Btu/h maintained down to 5°F outdoor ambient — built for cold-climate performance.
- Puron Advance (R-454B) refrigerant reduces global warming potential by 75% versus older refrigerants while remaining non-ozone-depleting.
- Supports up to five indoor zones off a single outdoor condenser for whole-home zoning flexibility.
- ENERGY STAR certified at up to 25 SEER2 and 11.3 HSPF2 (family-level; confirm exact 18K HSPF2 in the table below).
| Spec | Value | Unit |
|---|---|---|
| Model | 37MGHAQ18CA3 | — |
| Component Role | Outdoor Condenser (Outdoor Unit Only) | — |
| Cooling Rated Capacity (DOE A2, 95°F) | 19000 | Btu/h |
| Heating Rated Capacity (DOE H12, 47°F) | 20000 | Btu/h |
| Heating Maximum Capacity (17°F) | 19000 | Btu/h |
| Heating Maximum Capacity (5°F) | 19000 | Btu/h |
| SEER2 | 25 | Btu/h.W |
| HSPF2 (Region IV) | 10.5 | Btu/h.W |
| EER2 (DOE A2, 95°F) | 15 | Btu/h.W |
| Voltage | 208/230; 1Ph; 60 | V;Ph;Hz |
| Outdoor Sound Pressure Level | 61.5 | dBA |
| Net Weight | 137.35 | lb |
| Refrigerant Type | R-454B | — |
| Compressor Type | Variable-speed | — |
| Unit Height | 31.89 | in |
| Unit Width | 37.24 | in |
| Unit Depth | 16.14 | in |
| Min Piping Length per Indoor Unit | 10 (3) | ft (m) |
| Standard Piping Length per Indoor Unit | 24.6 (7.5) | ft (m) |
| Max Piping Length (no additional charge) | 73.8 (22.5) | ft (m) |
| Total Maximum Piping Length per System | 196.9 (60) | ft (m) |
| Outdoor Airflow | 2130.7 | CFM |
| MCA / MOCP | [NEEDS VERIFICATION] | — |
Note: See "Resources (System Manuals and Warranty)" Tab above for full specifications.
Compatibility & Fitment
- Compatible with 208/230V; 1 Phase; 60Hz dedicated circuits only.
- Designed to pair with Carrier indoor heads that are AHRI-certified as matched combinations with the 37MGHA family at the 18K size.
- Supports up to five indoor zones on this outdoor unit per the manufacturer overview.
- Not compatible with 115V-only circuits.
- Not a listed match for indoor units outside the AHRI-certified 37MGHA family combinations.
- Line set, wall sleeve, mounting bracket, and indoor unit(s) are NOT included with this listing — all sold separately.
FAQ
What breaker size do I need for this system?
[NEEDS VERIFICATION] — the manufacturer data provided does not list a breaker size (MCA/MOCP) for the 37MGHAQ18CA3. Confirm with the nameplate or installation manual before wiring.
Is professional installation required to keep the warranty valid, or is this a true DIY kit?
This is not a DIY kit. It uses R-454B refrigerant (an A2L mildly flammable refrigerant) and requires professional installation by a licensed HVAC contractor to maintain the manufacturer warranty.
Is the line set included, and if not, what size do I need to buy?
The line set is not included and is sold separately. For the 18K size, the standard piping length per indoor unit is 24.6 ft (7.5 m), with a minimum of 10 ft (3 m) and a maximum of 73.8 ft (22.5 m) per indoor unit with no additional refrigerant charge, up to a total system maximum of 196.9 ft (60 m).
Does this system work in cold climates (low-ambient heating)?
Yes. The 18K outdoor unit is rated for a heating maximum capacity of 19,000 Btu/h at 17°F and 19,000 Btu/h at 5°F outdoor ambient temperature.
How many indoor heads can I run off this outdoor unit?
The manufacturer overview text states support for up to five indoor units on this multi-zone system (some sections of the source documentation reference up to six zones — confirm exact zone limit for the 18K size with the installation manual: [NEEDS VERIFICATION]).
Compliance & Warranty
Installation by a licensed HVAC professional is required to maintain warranty. This unit uses R-454B (A2L) refrigerant, which requires EPA Section 608 certification to handle. Under Carrier's Consumer Choice Warranty, upon timely registration on eligible equipment, buyers may select either a 10-year parts-only limited warranty or a 5-year parts plus 3-year labor limited warranty. This unit is ENERGY STAR certified. Line set, wall sleeve, mounting bracket, and indoor unit(s) are sold separately and are not included with this outdoor condenser purchase.
