Overcharged my mini split

[dnwong]

I had a line break and had to vac and install new freon. I think I put too much freon in the system as the pressures are in the RED on my guage. Initially, it was low so I kept adding (maybe it need to run a while before the pressures were accurate).

How do I get rid of the excess freon? I let some out but the pressure did not drop. Do I have shut the system down and let it cool down?

 

[jjrbus]

I had a line break and had to vac and install new freon. I think I put too much freon in the system as the pressures are in the RED on my guage. Initially, it was low so I kept adding (maybe it need to run a while before the pressures were accurate).

How do I get rid of the excess freon? I let some out but the pressure did not drop. Do I have shut the system down and let it cool down?

Not a tech, but everything I have read says minis are charged by weight not pressure and that correct weight is critical. May need to pay a tech that can evacuate and weight in new charge.

 

[Jim greengo]

The system has a certain operating pressure depending on multiple factors.

 

[Jackfre]

Curious what tools were used to decide how much you put in. Ask any mini manuf and they will tell you that the charge must be weighed in and correct. What did you do?

 

[metlmunchr]

Assuming its an inverter type unit, it operates with variable refrigerant flow controlled by compressor speed, an electronic expansion valve, and multiple temperature sensors. Normal charging methods using target subcooling or superheat values can't be used for charging.

Overcharging is the worst refrigerant related situation in a mini. They use one or more accumulators to store excess refrigerant during low refrigerant flow (low load) operation. Overcharging can result in overloading the accumulator(s) which then allows the compressor to be flooded with liquid refrigerant. Net result is a dead compressor. Gauge pressure cannot be used to detect how much refrigerant is in the system. The only acceptable method is to charge by weight.

You can buy a refrigerant charging scale for less than $100 from Amazon and do it yourself for far less than the price of a service call to recharge it. The factory charge weight should be stamped on the condensing unit nameplate.

 

[Sumboodie]

You cannot just "let some out". You need to charge by weight.

"Freon".. it it really an R-22 system?

 

[metlmunchr]

Freon has become a somewhat generic name for refrigerant and not specific to R22. DuPont owns the name and has used it for multiple refrigerants as well as licensing the name for use on certain replacement refrigerants produced by other companies. By the same token, as DuPont's patents expired on earlier refrigerants, generic products of the same formulations we're sold under the names Genetron and Isotron and a few other lesser known brand names.

IOW, there's nothing incorrect about the use of the word "Freon" by the OP as it doesn't signify a specific refrigerant.

 

[dnwong]

Well, I called the original dealer that I purchased it from. The unit was new. So, they sent me 2 tanks and a manifold guage set as well as a pressure chart for the minisplits.

I guess this let me to believe that I needed to monitor the pressures while adding freon.

https://i.imgur.com/wBfU966.png

 

[dnwong]

Curious what tools were used to decide how much you put in. Ask any mini manuf and they will tell you that the charge must be weighed in and correct. What did you do?

The dealer sent me guage set and a PT chart for the mini split along with replacement freon. I guess that was a poor assumption on my part.

 

[Jim greengo]

Freon has become a somewhat generic name for refrigerant and not specific to R22. DuPont owns the name and has used it for multiple refrigerants as well as licensing the name for use on certain replacement refrigerants produced by other companies. By the same token, as DuPont's patents expired on earlier refrigerants, generic products of the same formulations we're sold under the names Genetron and Isotron and a few other lesser known brand names.

IOW, there's nothing incorrect about the use of the word "Freon" by the OP as it doesn't signify a specific refrigerant.

What he said.

 

[Wrench97]

Well, I called the original dealer that I purchased it from. The unit was new. So, they sent me 2 tanks and a manifold guage set as well as a pressure chart for the minisplits.

I guess this let me to believe that I needed to monitor the pressures while adding freon.

https://i.imgur.com/wBfU966.png

Here is the image you tried to post


Though I do find it strange they sent you refrigerant and a chart to do it your self in this day and age of EPA licensing.

 

[KenC]

Here is the image you tried to post


Though I do find it strange they sent you refrigerant and a chart to do it your self in this day and age of EPA licensing.

While Pioneer units are not advertised a DIY units, the instructions are clearly written for an owner install.

Also, they are supposedly not warranted for DIY, I had an indoor unit blower motor fail. They sent a new one overnight, no questions asked.

They will also supply parts direct when needed.

I use a high quality shipping/postal scale to weigh the charge when needed. Just a little inconvenient as it is not battery powered like the 'real' scales.

 

[dnwong]

I am so far very happy with their support and responsiveness. Given all the items they sent me, I guess I misunderstood the recharge process. The 9K unit uses exactly 1 can of r410a (28oz). However, I received 2 cans and a set of guages, so I assume I should fill according to the PT charts. They don't have weekend tech support, otherwise, I would have verified whether I needed to use the second can.

 

[rlitman]

I am so far very happy with their support and responsiveness. Given all the items they sent me, I guess I misunderstood the recharge process. The 9K unit uses exactly 1 can of r410a (28oz). However, I received 2 cans and a set of guages, so I assume I should fill according to the PT charts. They don't have weekend tech support, otherwise, I would have verified whether I needed to use the second can.

R410a is a blend of two refrigerants. In gaseous form, they separate, so in order to charge an R410a system, you must fill it in liquid form. This, in addition to needing to charge by weight is probably your issue.

 

[LS6 Tommy]

Well, I called the original dealer that I purchased it from. The unit was new. So, they sent me 2 tanks and a manifold guage set as well as a pressure chart for the minisplits.

I guess this let me to believe that I needed to monitor the pressures while adding freon.

https://i.imgur.com/wBfU966.png

If you're not an EPA certified tech, they shouldn't have sold you ANYTHING that allows you to charge your system. That chart is for checking operating pressures, not charging. The only way to do it is to recover the remaining refrigerant, evacuate the system and weigh in the proper charge.

Tommy

 

[Terry D]

Mini splits are different animals, they have variable speed compressors and electronic expansion valves which adjusts for the demand of the heating and cooling load. As already said, the only way is weigh in the proper charge after recovering and evacuating the system. The correct charge will be on the name plate on the unit. Remember, that is for the standard line set that came with the unit. If you have added more line set, you will have to look in the manual to see how much more refrigerant to add. Since you also had a leak, I would also suggest pressure testing with nitrogen.