Mr Cool DIY 9k, 12k, 18k, 24k, 36k Breaker Sizes (Specs Sheets)

What breaker size do you need for a MrCool mini split?

That’s quite easily answered. If you are wondering what fuse size (in amps) you need for your MrCool unit, just check the specification sheet.

Every MrCool specification sheet has a line with “Maximum Fuse (Breaker)” specs under the “Electrical Parts” section.

Here’s the problem:

These specs sheets for MrCool units are notoriously difficult to find. Yes, if you know where the specs sheet that came with the unit is, you just check that one. These specs sheets, however, get lost quite often. Googling for the MrCools specs and breaker sizes don’t always give you the answers you were looking for.

That’s why we have transcribed the breaker sizes for all MrCool units (including DIY units) from the specs sheets we haven’t yet lost. 🙂

mr cool diy breaker sizes
The best-selling MrCool DIY 12k unit (115V), for example, requires a 20A breaker.

You will find these maximum fuse sizes for all different MrCool series and units below. Let’s start with the best-selling DIY units:

Mr Cool DIY Single-Zone Breaker Sizes (20A, 25A, 30A)

The Mr Cool DIY Single Zone series is comprised of 4 different units; namely 12k, 18k, 24k, and 36k units.

Here are the breaker sizes as per the specs sheets:

Model: Serial Number: Maximum Breaker Size:
Mr Cool DIY 12k DIY-12-HP-WMAH-115B 20.0 Amp Breaker
Mr Cool DIY 18k DIY-18-HP-WMAH-230B 20.0 Amp Breaker
Mr Cool DIY 24k DIY-24-HP-WMAH-230B 25.0 Amp Breaker
Mr Cool DIY 36k DIY-36-HP-WMAH-230B 30.0 Amp Breaker

As you can see, the DIY series uses 20A, 25A, and 30A. Example: Mr Cool DIY 24k breaker size is 25 amps. This is the maximum size.

Mr Cool DIY Multi-Zone Breaker Sizes (20A, 25A, 30A)

With multi-zone mini splits, you have two breaker sizes you need to check:

  • Outdoor unit – Heat pump condenser.
  • Indoor unit – Wall-mounted air handler.

For the smaller 3-zone outdoor MrCool DIY unit (DIY-MULTI3-18HP230), you will need a 35A maximum breaker. For the bigger 4-zone outdoor unit (DIY-MULTI4-27HP230), you will need a 45A maximum breaker.

Here is a chart of MrCool DIY multi-zone indoor unit breaker sizes:

Indoor Unit Model: Serial Number: Maximum Breaker Size:
Mr Cool DIY 9k Multi-Zone DIY-09-HP-WMAH-230B 15.0 Amp Breaker
Mr Cool DIY 12k Multi-Zone DIY-12-HP-WMAH-230B 15.0 Amp Breaker
Mr Cool DIY 18k Multi-Zone DIY-18-HP-WMAH-230B 15.0 Amp Breaker
Mr Cool DIY 24k Multi-Zone DIY-24-HP-WMAH-230B 15.0 Amp Breaker

In short, all Mr Cool DIY Multi-Zone indoor units require a 15A breaker.

Mr Cool Advantage Series (20A, 25A, 30A)

Advantage Series MrCool units have to be installed by a professional. They are not DIY units.

Here are the breaker sizes for indoor and outdoor units:

Advantage Model: Serial Number: Maximum Breaker Size:
Mr Cool Advantage 9k 115V A-09-HP-WMAH-115B 15A Indoor / 20A Outdoor
Mr Cool Advantage 12k 115V A-12-HP-WMAH-115B 15A Indoor / 20A Outdoor
Mr Cool Advantage 9k 230V A-09-HP-WMAH-230B 10A Indoor / 15A Outdoor
Mr Cool Advantage 12k 230V A-12-HP-WMAH-230B 15A Indoor / 15A Outdoor

At higher voltage (230V) you need less amps to generate the same amount of power (wattage). That’s why you need bigger breakers with 115V MrCool Advantage units.

MrCool Olympus E Star Series Breaker Sizes

These are older MrCool models. Here are the breaker sizes:

Olympus E Model: Serial Number: Maximum Breaker Size:
Mr Cool Olympus E 9k O-09-WMAH-230A 15.0 Amp Breaker
Mr Cool Olympus E 12k O-12-WMAH-230A 15.0 Amp Breaker
Mr Cool Olympus E 18k O-18-WMAH-230A 20.0 Amp Breaker
Mr Cool Olympus E 24k O-24-WMAH-230A 25.0 Amp Breaker

MrCool Olympus Hyper Heat Series Breaker Sizes

Olympus Model: Serial Number: Maximum Breaker Size:
Mr Cool Olympus 9k O-09-WMAH-230A 15.0 Amp Breaker
Mr Cool Olympus 12k O-12-WMAH-230A 15.0 Amp Breaker
Mr Cool Olympus 18k O-18-WMAH-230A 25.0 Amp Breaker
Mr Cool Olympus 24k O-24-WMAH-230A 30.0 Amp Breaker

This is about it. If you would need a to know a breaker size for a specific MrCool model, just use the comments below and we’ll find the breaker size for you.

2 thoughts on “Mr Cool DIY 9k, 12k, 18k, 24k, 36k Breaker Sizes (Specs Sheets)”

  1. Purchased a mr. cool 36k, 2 zone, (24K and 12k) control units, I’m running #8/2 to disconnect and 8/2 to terminal block, however I had to file down the terminal ends so it would fit into the slot, you would think mr cool would have addressed this. Very tight.

    Reply
  2. In addition, I worry about the amperage draw and how it will affect the terminals, because I had to file them down in order to fit in the terminal block.

    Reply

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