- Parts Needed to Recharge a Window AC unit
- How To Recharge a Window Air Conditioner
- How To Add a Bullet Schrader Valve
- Window Air Conditioner Refrigerant Type
- Window Air Conditioner Refrigerant Pressure
- Recharging a Window AC Unit Tips
If you have a window air conditioner unit that is not working properly anymore, it may only need a refrigerant charge to get it working again.
Recharging the refrigerant in a window air conditioner is not done often, with most people buying a new unit when an old unit fails.
However, window air conditioners can 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 refrigerants, be sure to study the basics.
Parts Needed to Recharge a Window Air Conditioner
- Bullet Valve (Schrader Valve)
- Refrigerant (Usually R410a)
- Recharge Hose or HVAC Gauges
The main things needed to charge a window air conditioner unit are a bullet valve, refrigerant, and HVAC Gauges.
How To Recharge a Window Air Conditioner
- Attach a Bullet Schrader Valve to the low-pressure line.
- Attach the refrigerant can to the hose.
- Attach the recharge hose to the Schrader Valve.
- Open the valve on the recharge hose, which will add refrigerant to the system.
How To Add a Bullet Schrader Valve
Window air conditioners do not usually have a service port that is easily fixed with a low-cost bullet valve.
A bullet valve is simple to attach by using an Allen wrench to tighten the screws on it, which has a piercing valve that goes into the line.
It is usually attached to the refrigerant low-pressure line (big copper line).
Bullet Piercing Valve on Amazon
Supco BPV21 Bullet Piercing Valve
Read Here for detailed Instructions on Installing a Service Port on a Window A/C unit.
Window Air Conditioner Refrigerant Type
Many old units will use R22, which is not manufactured anymore, and newer units usually use R410a.
There are many online videos and forums of people using R134a refrigerants to recharge window AC units.
When adding refrigerant, they should never be mixed since the system was not designed for this.
Also, the oils used in HVAC systems can vary and damage the compressor or other parts.
Many people online and on YouTube claim to have good success using R134a refrigerant in R22 and R410a systems which I wouldn’t recommend.
The reason they are using R134a is it is widely used in vehicle AC systems with low-cost cans sold online and auto parts stores.
The refrigerant that was designed for the system should be added with no mixing of refrigerant.
Window Air Conditioner Refrigerant Pressure
This means each window AC unit will need the correct pressure or it will not cool.
If a unit is low on refrigerant, the pressure will be lower, and the system will not work.
If a unit is overfilled, the pressure will be too high, and the system will not work.
For this reason, it is necessary to get the pressure correct when adding refrigerant so as not to overfill the system.
I would not go above 35-40 PSI on the low-pressure line before testing the unit and seeing if it starts cooling.
Starting at a lower pressure such as 30 PSI is best, and testing the unit for cooling.
If the unit is not cooling, slowly raise the pressure until it does start cooling.
HVAC gauges or a recharge hose with a pressure gauge, and a temperature pressure chart, will be needed to get the correct pressure.
Example Recharge hose and Bullet Valve Kit on Amazon
Aupoko A/C R134A Refrigerant Charging Hose Kit, Recharge Hose with Gauge, R13A Can Tap and Quick Couple, R410A Straight Swivel Adapter, Piercing Tap Valve Kits, 2PC 1/4’’ Adapters with Valve Core
Recharging a Window Air Conditioner Unit Tips
- Find and Fix Any Leak
- Install a Service Port (Schrader Valve)
- Recharge the Unit
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.
It is common for leaks to occur at joints which often require soldering them together again.
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 usually installed on the low-pressure line to add refrigerant, which is the larger diameter line.
Example Bullet Piercing Valve on Amazon
Supco BPV21 Bullet Piercing Valve
After any leak is fixed and a service port has been installed, the unit is ready for the refrigerant.
HVAC gauges and the correct refrigerant is needed.
R410a can be bought at air conditioning supply stores or even online on eBay.
Check here for R410a Refrigerant prices on eBay
Hook up your gauges to the service port and the refrigerant tank.
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.
The above are the basic steps involved in recharging a window air conditioning unit.
Keep in mind there will always be design differences between manufacturers.
Also, be sure always to follow safety procedures as you would with any HVAC unit.