How To Recharge a Window Air Conditioner Unit Basics

By | March 14, 2020

How To Recharge a Window Air Conditioner Unit Basics
Recharging the refrigerant on a window air conditioner is not something many do with most buying a new unit when an old unit fails.

Windows air conditioners can however be recharged with refrigerant and be put back to work cooling a room or space.

Recharging a unit is not difficult but if you have never worked with HVAC refrigerant be sure to study the basics.


  1. Find and Fix Any Leak
  2. The first step is to check for leaks. If a unit has a very slow leak over the course of a year or more it will only need a boost.

    A fast leak will need to be fixed and repaired before refilling it.

    There are a few methods for finding a leak from a visual inspection to filling a unit with Nitrogen and using soap to find the leak.

    Leak detectors can also be bought which sniff out a refrigerant leak and will make a fast audible beep as it moves closer to it.

    Read Here For More information on Refrigerant Leak Detectors.

    Common leaks can occur at joints which often require soldering them together again.

  3. Install a Service Port
  4. Small air conditioner units will not usually have a service port to hook up gauges.

    Installing a service port is an easy task and requires soldering in a port or using a piercing valve kit.

    A piercing valve is easy to install and the most common method to get a Schrader Valve on a unit.

    Service ports are installed on the low pressure line which is the larger diameter line.
    Bullet Piercing Valve on Amazon
    Supco BPV21 Bullet Piercing Valve

    Read Here for Instructions on Installing a Service Port on a Window A/C unit.

  5. Recharge the Unit
  6. After any leak is fixed and a service port has been installed the unit is ready for refrigerant.

    HVAC gauges and the correct refrigerant is needed.

    Most units today will use R410a but be sure to read the service tag on the unit to be sure.
    Recharge a Window Air Conditioner Unit

    R410a can be bought at air conditioning supply stores or even online on eBay.

R410a Refrigerant on eBay
Hook up your gauges to the service port and the refrigerant tank.
How To Recharge a Window Air Conditioner Unit
Be sure to know what the PSI should be at before starting. Do not overfill the unit.

Also be sure to watch your pressures on the gauges along with a temperature pressure chart to know what it should be.
Recharge a Window Air Conditioner Unit HOW TO
The above are the basic steps involved in recharging a window air conditioning unit.

Keep in mind there will always be design differences between manufactures.

Also be sure to always follow safety procedures as you would with any HVAC unit.



One thought on “How To Recharge a Window Air Conditioner Unit Basics

  1. Doug

    Great information about how to recharge a window AC unit. How to Find the leak and fixing it plus the pierce adapter all great information for the DIY types. I’ll get a certified refrigeration technician on the task based on the expertise required.


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