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MRCOOL / DIY 5th Gen Multi-Zone

MRCOOL DIY 5th Gen Multi-Zone 55k 6-Zone Outdoor Unit

Model data is drawn from manufacturer, retailer, and certification sources. Missing specifications remain marked as not published.

6 zoneDIY installDIY-marketedCurrent
Data completeness: 97%
Last verified
Jul 20, 2026

SplitAtlas score

not yet rated - data incomplete

Methodology
  • no scoring run is available

1. Summary

The DIY 6-Zone 55k is the largest and coldest-rated condenser in MRCOOL's self-install multi-zone line: up to six heads, 55,000 BTU nominal, and - uniquely in this family - rated to operate down to -22F rather than -13F. It is the pick when a large home needs both maximum zones and the deepest documented cold-weather operation.

Rated cooling

Certified per indoor-unit combination, not per outdoor unit

Rated heating

Certified per indoor-unit combination, not per outdoor unit

2. Best-fit use cases

A large home in a genuinely cold climate that needs many zones and the deepest documented low-temperature operation from a single outdoor unit - the case where the -22F rating, not efficiency numbers, drives the choice.

3. Key specifications

Manufacturer
MRCOOL
Brand
MRCOOL
Product line
DIY 5th Gen Multi-Zone
Model number
DIY-MULTI6-55HP230D-O
Indoor unit model
Indoor heads are selected separately on a multi-zone system
Outdoor unit model
DIY-MULTI6-55HP230D-O
Number of zones
6
Max indoor units
6 unitsVerified - manufacturer technical document
Rated cooling capacity
Certified per indoor-unit combination, not per outdoor unit
Rated heating capacity
Certified per indoor-unit combination, not per outdoor unit
Voltage
208-230VVerified - manufacturer technical document
MCA
43 AVerified - manufacturer technical document
Maximum fuse or breaker size
45 AVerified - manufacturer technical document
Breaker needed
not published
SEER2
Certified per indoor-unit combination, not per outdoor unit
EER2
Certified per indoor-unit combination, not per outdoor unit
HSPF2 (Region 4)
Certified per indoor-unit combination, not per outdoor unit
HSPF2 (Region 5)
Certified per indoor-unit combination, not per outdoor unit
COP
not published
COP at 47F
not published
COP at 5F
not published
Minimum outdoor heating temperature
-22 FVerified - manufacturer technical document
Minimum outdoor cooling temperature
-22 FVerified - manufacturer technical document
Maximum outdoor temperature
122 FVerified - manufacturer technical document
Indoor noise range
Indoor heads are selected separately on a multi-zone system
Outdoor noise rating
64 dBAVerified - manufacturer technical document
Indoor weight
Indoor heads are selected separately on a multi-zone system
Outdoor weight
245.81 lbVerified - manufacturer technical document
Refrigerant
R-454BVerified - manufacturer technical document
Refrigerant charge
151.68 ozVerified - manufacturer technical document
Manufacturer coverage
not published
Line-set size
1/4 in liquid / (3/8 x4), (1/2 x2) suction
Included line-set length
Indoor heads are selected separately on a multi-zone system
Maximum line-set length
221 ftVerified - manufacturer technical document
Max line set per indoor
75 ftVerified - manufacturer technical document
Maximum elevation difference
33 ftVerified - manufacturer technical document
Max height between indoor units
24 ftVerified - manufacturer technical document
Wi-Fi support
Indoor heads are selected separately on a multi-zone system
Energy Star status
not published
AHRI certification number
Certified per indoor-unit combination, not per outdoor unit
Warranty
5 years parts / 7 years compressor
DIY installation status
DIY-marketed
Retail price
$3,809.00
Installation type
DIY install
Available retailers
HVACDirect
Manual links
AHRI certificate for DIY-MULTI6-55HP230D-O, MRCOOL DIY Series Multi-Zone Installation & Owner's Manual, MRCOOL R-454B Compatibility, MRCOOL DIY 5th Gen Multi-Zone 55k 6-Zone Outdoor Unit MRCOOL support article, MRCOOL DIY 5th Gen Multi-Zone brochure
Specification sheet
MRCOOL DIY 5th Gen Multi-Zone brochure
Last verified date
Jul 20, 2026

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Paid link

Check price at HVACDirect

$3,809 / Fresh price - checked Jul 20, 2026

Compatible indoor units

This is an outdoor unit. You choose its indoor heads separately - up to the maximum this condenser supports - and you can mix room sizes and styles across the zones. The models below are the heads this unit is documented to pair with.

  • Hybrid air handlers

    24k, 36k

    Model numbers
    • 24k: DIY-24-HP-MUAH-230D25-O
    • 36k: DIY-36-HP-MUAH-230D25-O

  • One-way ceiling cassettes

    6k, 9k, 12k, 18k

    Model numbers
    • 6k: DIYCASSETTE06HP-230D25-O
    • 9k: DIYCASSETTE09HP-230D25-O
    • 12k: DIYCASSETTE12HP-230D25-O
    • 18k: DIYCASSETTE18HP-230D25-O

  • Wall-mounted air handlers

    6k, 9k, 12k, 18k, 24k, 36k

    Model numbers
    • 6k: DIY-06-HP-WMAH-230D25-O
    • 9k: DIY-09-HP-WMAH-230D25-O
    • 12k: DIY-12-HP-WMAH-230D25-O
    • 18k: DIY-18-HP-WMAH-230D25-O
    • 24k: DIY-24-HP-WMAH-230D25-O
    • 36k: DIY-36-HP-WMAH-230D25-O

Sizing note: do not just add up the rooms. Multi-zone condensers have a maximum total connected capacity, and connecting more head capacity than the unit is rated for is a common installer mistake that hurts efficiency and comfort. Match total head capacity to the condenser's rating.

4. Strengths

  • The deepest cold rating in the DIY multi-zone family: operation documented to -22F, versus -13F on every smaller sibling.
  • Highest capacity here - up to six zones, 55,000 BTU nominal, from one condenser.
  • DIY Quick Connect line sets; self-install-friendly 5/7-year warranty.
  • R-454B.

5. Weaknesses

  • No certified combination efficiency rating (multi-zone; see the page).
  • 43 A minimum circuit ampacity - the heaviest electrical load in the family; panel capacity must be confirmed.
  • A six-zone install is a major undertaking - most owners will hire the labor even on this DIY-capable unit.
  • Part-load efficiency penalty is real when a large home runs only a zone or two off a 55k compressor.
  • Size to the connectable-capacity limit, not the sum of the rooms.

6. Climate suitability

Minimum heating ambient
-22 FVerified - manufacturer technical document
Rated heating at 5F
Certified per indoor-unit combination, not per outdoor unit
Rated heating at 17F
Certified per indoor-unit combination, not per outdoor unit
Rated heating at 47F
Certified per indoor-unit combination, not per outdoor unit

7. Electrical requirements

Voltage
not published
Voltage range
208-230VVerified - manufacturer technical document
Phase
1Verified - manufacturer technical document
Frequency
60 HzVerified - manufacturer technical document
MCA
43 AVerified - manufacturer technical document
Breaker needed
not published
Maximum breaker size
not published
Maximum fuse size
45 AVerified - manufacturer technical document
Maximum cooling current
not published
Maximum heating current
not published
Manufacturer wire notes
not published

8. Installation considerations

Liquid line
1/4 inVerified - manufacturer product page
Suction line
(3/8 x4), (1/2 x2)Verified - manufacturer product page
Precharged length
not published
Included line-set length
Indoor heads are selected separately on a multi-zone system
Maximum line-set length
221 ftVerified - manufacturer technical document
Max line set per indoor
75 ftVerified - manufacturer technical document
Max height between indoor units
24 ftVerified - manufacturer technical document
Indoor dimensions
Indoor heads are selected separately on a multi-zone system
Outdoor dimensions
37.48 x 16.34 x 52.48 inVerified - manufacturer technical document
Indoor weight
Indoor heads are selected separately on a multi-zone system
Outdoor weight
245.81 lbVerified - manufacturer technical document
Drain size
not published

9. Operating-cost estimate

not published

10. Comparable models

not published

Frequently asked questions

Can I install the MRCOOL DIY 5th Gen Multi-Zone 55k 6-Zone Outdoor Unit myself, or do I need a pro?
MRCOOL DIY 5th Gen Multi-Zone 55k 6-Zone Outdoor Unit is sold as a DIY-installable system. The electrical circuit is the part that is not DIY: plan on a licensed electrician for the dedicated circuit, and check whether your local permit office requires a permit for the install.
Will the MRCOOL DIY 5th Gen Multi-Zone 55k 6-Zone Outdoor Unit keep heating in a cold winter?
Rated heating operation extends down to -22 F. Match that published heating floor against your climate's design temperature - below the low-ambient rating, output can fall off or the system can pause to protect itself.
What electrical circuit does the MRCOOL DIY 5th Gen Multi-Zone 55k 6-Zone Outdoor Unit need?
Published electrical requirements: 208-230V voltage, 43 A minimum circuit ampacity, and 45 A maximum breaker or fuse sizing. Confirm the final circuit against the unit nameplate and local code with a licensed electrician.
How far can the outdoor unit be from the indoor head?
The published maximum line-set length is 221 ft. Longer runs than the included set allows typically mean added refrigerant and a pro visit, so measure the planned routing before ordering.
What warranty does the MRCOOL DIY 5th Gen Multi-Zone 55k 6-Zone Outdoor Unit carry?
The manufacturer publishes 5 years parts coverage and 7 years compressor coverage. Registration requirements and proof of qualified installation commonly affect coverage, so read the warranty terms before install day.

11. Data sources

  • MRCOOL: MRCOOL DIY 5th Gen Multi-Zone brochureVerified - manufacturer technical document

    Covers Frequency, Maximum fuse size, Minimum circuit ampacity, Phase, Voltage range, Outdoor dimensions and more

  • MRCOOL Support: MRCOOL DIY 5th Gen Multi-Zone 55k 6-Zone Outdoor Unit MRCOOL support articleVerified - manufacturer product page

    Covers Liquid line size, Suction line size

  • MRCOOL: MRCOOL DIY Series Multi-Zone Installation & Owner's ManualVerified - manufacturer technical document

    Covers Maximum elevation difference, Maximum line-set length, Max height between indoor units, Max line set per indoor, Minimum outdoor cooling temperature, Minimum outdoor heating temperature and more

  • MRCOOL: MRCOOL 5th Generation DIY Series Limited WarrantyVerified - manufacturer technical document

    Covers Compressor warranty, Parts warranty

12. Last updated date

Jul 20, 2026