No movement on High Side

[extrakatana]

I'm excited to learn more from this forum! One of my first challenges is trying to figure out the attached reading on the video.

The video shows with a little low on coolant but even when I add coolant, the Low side goes way up but just like on this video, the High side stays around 50.

The L side does get drawn down when the compressor engages but nothing on the high.

2013 Nissan Altima.
System blows Warm Air
Ambient was low the day readings were taken. Performs the same on high side on 75f day.
I believe this system does have TXV
double-checked knob positions on Gauge. If you look closely to the video you can see the high side move ever-so little
When I did add 134a on a 75f day, the low side definitely increased while the High side stayed slightly over 50

[Tom Greenleaf]

Welcome and hope we can help: First best to say what this is, year, make, model at least.
Next know that gauges don't tell you a system is properly "full" rather is info that it's in range.

List of questions always come. Why did you touch it at all usually complaint of poor cooling.

What is the temp in Fahrenheit of the vehicle, engine area and air temps right at the thing too not a forecast. Next is what is your source of refrigerant and how warm is it?

Why? It's all about temp/pressures when and where then performance.

Is this a CCOT system or TXV set up will come but the problem is obvious to me so far already.

It's either too cold to be working on it if you added a thing it's below range of just "static pressure" to operate. I see 50 PSI means it's about 50F around you, so is source.

Now that's enough for a compressor to engage but way to low it actually means it's 50F outside or this system is almost empty you should be checking anything at 70F or more or results will be lousy.

Engine heat would spike the least amount in a system to 50 PSI if it holds at all could be about zero refrigerant in it quick heat of warmed up engine would show that. Plain air expands with temps - follow me?

So let's find out what the scene really is it's too low and also a chance high side port or gauges are not reading properly at all or valves where they should be AKA the knobs of the set,

[Tom Greenleaf]

More right away copy and print the chart if you wish: > https://forum.aircondition.com/forum...pressure-chart <

Will just add while on this that pressure don't and can't tell how full a system is. The only way is start from a well held vacuum and charge the exact known weight of refrigerant without much guessing or you need more equipment or help to do that,

[Cusser]

We used to have a 1994 Suburban, factory R134a. To get a real high pressure reading, I had to squeeze my high pressure fitting tight with my hand to open up the valve inside to get a high side reading. As soon as I released my hand squeezing, no reading.

[Nacho]

The most common cause of that is the receiver/drier or cartridge. This may be confirmed by a cool/cold filter and liquid line. Another suspect is the compressor's refrigerant control valve. I'd try the drier first