DIY Mini Split ReCharge Kit

DIY mini split recharge kit

DIY Mini Split ReCharge

How To Recharge Your R410a MiniSplit AC or Heat Pump

If you bought or installed a mini split AC or Heat Pump for your grow or home with precharged lines it’s likely you’re not getting maximum cooling power, here’s a kit for a DIY Mini Split ReCharge kit that works! By law, in most places, ACs and Heat Pumps supplied with pre-charged lines cannot be shipped charged to full capacity. While convenient and affordable to install following the manufacturer’s instructions, you may be only realizing half of the cooling power your unit can produce. If you sized up your AC for your home or grow room carefully and find things are still getting too warm, this could be the reason for it.

[quote]If you have been operating your mini split heat pump or AC for your home or grow room with regularity for over a year, it’s quite possible your system could benefit from a top-up even if it was professionally installed with a full charge (versus half charge with DIY pre-charged lines).[/quote]

mini split heat pump

While the principles may be similar in recharging or topping up different mini split systems, this review of Chem Penn’s DIY mini split recharge kit from The Refrigerant Guys is for Air Conditioner or Heat Pump units that operate with environmentally friendlier R410a refrigerant—this is most newer models, but it’s something you need to be absolutely certain of.  The wrong refrigerant in the wrong system could damage your investment—check the specifications of the unit you have. YOU MAY VOID YOUR WARRANTY BE RECHARGING THE SYSTEM YOURSELF, but it doesn’t mean that you can’t do it effectively and easily to gain significant cooling power from your system.

If you have been operating your mini split heat pump or AC for your home or grow room with regularity for over a year, it’s quite possible your system could benefit from a top-up even if it was professionally installed with a full charge (versus half charge with DIY pre-charged lines).

r401a recharge kit

The Chem Penn DIY mini split recharge kit comes with everything you need right out of the box, including a handy gauge and detailed instructions to see and verify the level of charge your system is operating at and top it off with up to 900 grams of R410a refrigerant.

DIY Mini Split ReCharge, Step By Step:

***Make sure you are wearing gloves and protective eyewear in case of accidental contact with refrigerant.***

First, make sure your system is running—ie the compressor is operating. It is very important that it doesn’t stop running while you are performing this process.  Just turn the thermostat to the lowest cooling setting possible and wait a couple minutes before getting started.

Connect the threaded end of the hose attached to the gauge and canister to the Low Pressure service port on your system (consult your AC/Heat Pump install guid or check with manufacturer if you need to verify).  There is an additional 5/16” adapter with Core Depressor supplied in case the 1/4” SAE fitting doesn’t match your system.

low pressure valve ac

Above: The low pressure valve on this unit is the downward facing connection on the right–works like a bicycle tube valve

TIP: have the right size hex key handy to shut off the valve that connects your lines to the air handler unit in case there is a problem during this process; otherwise just leave it open as it was. Don’t fear, this process is really simple and straightforward, although exercising caution is always a good policy.

checking ac refrigerant charge


Check the pressure indicator that is connected to the hose and recharge tank.  It is easy to read and see. Green (not enough charge), Blue (correct amount of charge), Yellow (too much charge), Red (system has major problems, contact a professional)

If in the Green Zone with your Chemo Penn DIY mini split recharge kit attached, turn the refrigerant canister upside down and press the button for 5 seconds.  See where the gauge goes while remaining attached with the system running for a few minutes; repeat as necessary.

Once you are in the Blue zone on the dial, disconnect the hose/canister from the system BEFORE shutting off the system or readjusting the thermostat back to your desired set temperature.

How Did the DIY Mini Split ReCharge Kit Work?

In our testing, it worked great—turns out the system was quite low and we needed the full 900 grams; possibly more.  That’s what happens when you don’t check or service your mini split AC or Heat Pump for an extended period; live and learn.

temperature check after

Using an infrared temperature checker, we determined we gained an extra 10 Deg F of Cooling Power, that’s around +20% from where we started.  Turns out we could have added more than the 900 gram canister.  If you’ve neglected your pre-charged line system for more than a couple of years you may considering ordering an extra canister.  You can save whatever you don’t used for your next annual check. Way cool.

For more information, contact: The Refrigerant Guys

About Erik Biksa 247 Articles
Erik Biksa has been writing about and discussing hydroponics growing, related technologies and cropping methods since 1999 in a variety of professional publications and platforms globally Erik has travelled the world learning and teaching modern growing techniques and technologies and is appreciated by many growers for his informative yet hands on approaches. Presently, he is the Editor at Grozine Hydroponics Mag.