MRCOOL Frequently Asked Questions (FAQ)

by Pete Lader July 29, 2022

A comprehensive guide and review to the most frequently asked questions from customers about MRCOOL products.

Is the DIY Mini Split Series truly DIY? 

The DIY System will have all the necessary parts for installation by a handy person.
The systems do not come with a power cord and requires 220V. You will need to directly connect an electrical whip to a disconnect box or circuit breaker and then to the breaker box. If you aren't comfortable doing this yourself, you'll need to hire an electrician (here's our preferred Installation Partner, Angi).

What are the biggest advantages of the 4th Generation Series?

Higher SEER for the Single-Zone 18K, 24K and 36K units
Added 18K and 48K Condenser
Improved Warranty
Improved durability of the communication wire

Read more in our 4th Generation Breakdown

What can I do about the excess coil/line set?

It is recommended to leave the remaining/excess line set coiled horizontally near the condenser and wrapped with protective tape. This will not impact performance whatsoever.

How much square feet can the DIY Air Handlers Cover?

9K BTU - 375
12K BTU - 500
18K BTU - 750
24K BTU - 1,000
36K BTU - 1,500

Can I use only one Air Handler with a Multi-Zone Condenser?

Nope! At least two Air Handlers need to be connected to a Multi-Zone Condenser and the total BTUs of the Air Handlers need to be at least 65% of the total BTUs of the Condenser. 

What does the SEER Rating mean?

An air conditioner’s SEER rating is a number value determining its cost-efficiency over an average cooling season. The higher the SEER rating, the less energy it needs to output its cooling capabilities.

Our team has published an amazing article that goes more in-depth that you can read here in our article: What is a SEER Rating?


  • I have a 3d gen 18K btu single zone unit. I know the 25 foot line set is precharged, but is there any refrigerant in the outside condenser unit? I think I have a low charge and need to evacuate the entire system and recharge. Also, how much R410a is needed to recharge?

    mike on

  • We installed a 27k multi port this week end with 18 k and a 9k wall units we got the 18k hooked up but the 9 k needs a Longer lines set that we ordered we started up the system with the 18k only hooked up and after a few minutes we got a p3 code so we turned it off Do I need to wait to get the longer line set and hook up the 9k unit to remove the code or is their something else

    Michael Lee on

  • was wondering why the breaker size on 24k units is so much higher than the competition The24 k units state 35 amps which changes the feed wire size from 10 to 8

    Jeff Schmitt on

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