In Focus｜MRCOOL® 27k 5th Gen 4-Zone DIY® Multi-Zone Bundle (9k + 18k) Air Handlers, (25ft + 50ft) Pre Charged R-454B Line Sets, 230V) — DIYM227HPW03D09

Product Description 
Model: DIYM227HPW03D09
Short Description
The MRCOOL DIYM227HPW03D09 bundle combines the DIY-MULTI4-27HP230D-O 27k 4-zone condenser, a 9k DIY wall mount air handler, an 18k DIY wall mount air handler, and two pre-charged QuickConnect® R-454B line sets (25 ft + 50 ft). This 5th Gen MRCOOL® DIY system is perfect when you need one standard line run and one long 50 ft run—ideal for upstairs rooms, detached spaces, or tricky installs—delivering efficient, smart-controlled heating and cooling for up to ~1,000–1,200 sq. ft. without hiring an HVAC pro.
Long Product Description
 
Overview: 27k Multi-Zone DIY Comfort with a Long-Run Line Set
The MRCOOL® DIYM227HPW03D09 Multi-Zone Bundle is built for homeowners who need two zones and flexible line set lengths, without paying contractor pricing.
 
This manufacturer bundle includes:

DIY-MULTI4-27HP230D-O – 27k BTU 4-Zone Multi-Zone Outdoor Condenser (230V, R-454B)
DIY-18-HP-WMAH-230D25-O – 18k BTU DIY 5th Gen Wall-Mount Air Handler (up to ~800 sq. ft.)
DIY-09-HP-WMAH-230D25-O – 9k BTU DIY 5th Gen Wall-Mount Air Handler (up to ~400 sq. ft.)
DIY25-1438-O – 25 ft Pre-Charged QuickConnect® Line Set (1/4” x 3/8”)
DIY50-1412C-O – 50 ft Pre-Charged QuickConnect® Line Set with DIYPRO® Cable (1/4” x 1/2”)

 
Use the shorter 25 ft line for a closer indoor unit and the 50 ft line for harder-to-reach zones like bonus rooms, upstairs areas, or detached offices. With up to 23 SEER2 and 9.5 HSPF2-4, this 5th Gen R-454B system is engineered for quiet, efficient, year-round comfort.
 
True DIY Install – Even on Long Runs
MRCOOL® designed the DIY series so serious DIYers can install it themselves:

Pre-charged R-454B QuickConnect® line sets – DIY25-1438-O and DIY50-1412C-O arrive pre-filled and sealed. No vacuum pump, no gauges, no refrigerant handling.
DIYPRO® cable with the 50 ft DIY50-1412C-O line set eliminates traditional electrical conduit and protects wiring from weather and critters.
Matching ports between DIY-MULTI4-27HP230D-O and the DIY wall mounts make hook-up clean and repeatable.

 
If you can mount brackets, drill through walls, and follow instructions, you can install this system yourself and save thousands over a contractor-installed multi-zone.

Smart, Quiet Comfort with Independent Zones
Both indoor units in this DIYM227HPW03D09 bundle are 5th Gen MRCOOL® DIY air handlers with full smart control:

SmartHVAC® app (iOS / Android)
Alexa & Google Assistant voice control
Follow Me® function (targets the remote’s location)
Dry Mode, Sleep Mode, Quiet Mode, multiple fan speeds

 
The 9k wall mount is perfect for a bedroom or office, while the 18k wall mount handles a big living space or open area. Each zone runs independently, so you can cool one room harder and keep the other mild—no more fighting over the thermostat.

Ideal Use Cases for DIYM227HPW03D09
This bundle is perfect when you need:

Zone 1 – 9k (DIY-09-HP-WMAH-230D25-O)

Bedroom, office, nursery, small den up to ~400 sq. ft.

Zone 2 – 18k (DIY-18-HP-WMAH-230D25-O)

Larger living room, open-concept area, big bonus room, shop, or studio up to ~800 sq. ft.

Long line run using the 50 ft DIY50-1412C-O –

Upstairs room far from the condenser
Finished attic, garage apartment, or detached office
Back-of-house room where a standard 16–25 ft line set won’t reach

 
Because the DIY-MULTI4-27HP230D-O condenser supports up to 4 indoor units, you still have expansion room to add more MRCOOL® DIY indoor units later (within total BTU guidelines).

R-454B, 5th Gen Efficiency & Future-Ready Refrigerant
This system uses R-454B, MRCOOL’s new, lower-GWP refrigerant:

Helps future-proof your HVAC investment
Works with MRCOOL’s 5th Gen multi-zone platform
Delivers strong efficiency with 23 SEER2 / 9.5 HSPF2-4

 
Paired with a DC inverter compressor, the system ramps capacity up and down instead of constantly cycling on/off like old-school systems, which means better comfort, less noise, and lower energy use.

Why Buy from the USA’s #1 Most Trusted MRCOOL Dealer
Buying this MRCOOL DIYM227HPW03D09 bundle from MRCOOL Direct – the USA’s #1 most trusted MRCOOL dealer means:

Verified, factory-fresh 5th Gen R-454B product
Help matching your line set lengths, breaker size, and zone layout before you order
Real support if you have questions during install or setup
No guessing which line sets or indoor units you need — this kit is already matched for 9k + 18k + 25 ft + 50 ft

Not sure if this is the right bundle for your home or project?
Call us before you buy and we’ll help confirm sizing, line set routing, and expansion options so you get it right on the first install.
 
 
Key Specifications
System Type

Brand: MRCOOL®
Series: DIY 5th Gen Multi-Zone
Bundle Model: DIYM227HPW03D09
Outdoor Condenser: DIY-MULTI4-27HP230D-O – 27k BTU, 4-Zone, 230V

Indoor Units:

DIY-18-HP-WMAH-230D25-O – 18k BTU wall-mount air handler (up to ~800 sq. ft.)
DIY-09-HP-WMAH-230D25-O – 9k BTU wall-mount air handler (up to ~400 sq. ft.)

Refrigerant: R-454B

Performance

Total Capacity: 27,000 BTU (2.25 tons)
Condenser Cooling Capacity: 26,000 BTU
Condenser Heating Capacity: 26,000 BTU
Efficiency: 23 SEER2, 12 EER2, 9.5 HSPF2-4, 7 HSPF2-5
Zones Supported: Up to 4 (2 used in this bundle)

 
Electrical

Voltage: 208/230V, 1-Phase, 60 Hz

Outdoor Condenser (DIY-MULTI4-27HP230D-O):

Max Fuse / Breaker: 25A
Minimum Circuit Ampacity (MCA): 23A

Indoor Units: powered from condenser via communication/power cable (no separate 230V circuit to each air handler in standard DIY configuration; follow MRCOOL® install guide and local code)

 
Line Sets (Included)

DIY25-1438-O – 25 ft Pre-Charged R-454B QuickConnect® Line Set

Liquid Line: 1/4”
Suction Line: 3/8”

DIY50-1412C-O – 50 ft Pre-Charged R-454B QuickConnect® Line Set with DIYPRO® Cable

Liquid Line: 1/4”
Suction Line: 1/2”

Coverage

9k Zone: up to ~400 sq. ft.
18k Zone: up to ~800 sq. ft.
Typical Total Coverage: ~1,000–1,200 sq. ft. (depending on layout, climate, insulation)

Certifications

UL Listed
ETL Listed
AHRI Certified
ENERGY STAR® (for qualifying models in series)
Proposition 65 Compliant

What’s Included
IN THIS COMPLETE DIY BUNDLE – MRCOOL DIYM227HPW03D09:

(1) DIY-MULTI4-27HP230D-O – 27k BTU 4-Zone Multi-Zone Outdoor Condenser (230V, R-454B)
(1) DIY-18-HP-WMAH-230D25-O – 18k BTU 5th Gen Wall-Mount Air Handler (up to 800 sq. ft.)
(1) DIY-09-HP-WMAH-230D25-O – 9k BTU 5th Gen Wall-Mount Air Handler (up to 400 sq. ft.)
(1) DIY25-1438-O – 25 ft Pre-Charged R-454B QuickConnect® Line Set (1/4” x 3/8”)
(1) DIY50-1412C-O – 50 ft Pre-Charged R-454B QuickConnect® Line Set w/ DIYPRO® Cable (1/4” x 1/2”)
Wireless remotes for each indoor unit
DIYPRO® cable, install hardware, and documentation as supplied by MRCOOL®
Manufacturer installation manuals and warranty information

 
 Frequently Asked Questions (FAQ)
 
Q: What is special about the DIYM227HPW03D09 bundle compared to other 27k kits?
A: This bundle includes one standard 25 ft line set and one extra-long 50 ft line set, making it ideal when one zone is close to the condenser and the other is farther away (upstairs room, garage apartment, or bonus room).
 
Q: What breaker size do I need for this system?
A: The DIY-MULTI4-27HP230D-O condenser specifies a maximum fuse/breaker of 25A and a minimum circuit ampacity (MCA) of 23A. Always have a licensed electrician size wiring and breakers according to local electrical code.
 
Q: Are the line sets pre-charged for DIY install?
A: Yes. Both DIY25-1438-O and DIY50-1412C-O are factory pre-charged with R-454B and use QuickConnect® fittings. No vacuum pump, no gauges, and no refrigerant handling required.
 
Q: How many rooms can this bundle handle?
A: Out of the box, this bundle is built for two zones: a 9k zone up to ~400 sq. ft. and an 18k zone up to ~800 sq. ft. The condenser can support up to 4 indoor units total, so you can add more MRCOOL® DIY air handlers later.
 
Q: Is this a good option for upstairs or long-line installations?
A: Yes. The 50 ft DIY50-1412C-O line set is perfect when the condenser is on the ground and the 18k air handler is upstairs or far away. The 25 ft line works great for a closer 9k zone.
 
Q: Do I really not need an HVAC tech?
A: The MRCOOL® DIY series is specifically engineered so homeowners can install it themselves using pre-charged QuickConnect® line sets and DIYPRO® cable. If you’re comfortable with tools and following instructions, you can DIY it. If not, you can still hire an installer and benefit from the simplified design.
 
Q: Who can help me make sure this is the right bundle before I order?
MRCOOL Direct (the USA’s #1 most trusted MRCOOL dealer) can help verify sizing, line lengths, breaker requirements, and expansion plans so you pick the right kit the first time.
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