Do window/wall AC units have low pressure cutouts?

[JHZR2]

We don’t run AC a whole lot, really just to cut humidity and heat on the worst days, and sometimes in bedrooms to sleep.

Out home has a wall mounted 24k btu Freidrich AC unit that we run maybe a few times a year. This year we ran it a bit more than usual, and noticed that it started to not be as cool as typical. Filter was cleaned, the unit runs fine, I hear the compressor kick on. But the coil doesn’t get cold.

In other systems, the compressor would not engage if the charge was too low. I don’t know why this unit would have a leak on the sealed system, but it’s something to check. But don’t wall and window units have a similar permissive sensor? Or do they just allow the compressor to run endlessly doing nothing buy burning electricity and itself up?

I do intend to pull the unit and wash the exterior coils. Maybe that’s part of it. But it’s a big annoyance for certain…. Potentially time to install a split in there, though then I’d need to do siding too…

 

[Cujet]

I think they typically have the low pres switch.

I use a window AC in my bedroom, despite having a 5T central AC. I like the cold at night but don't want the entire house to be cold in the AM. I seem to go through them every two or three years. Few of them actually work exceptionally well. The latest one, a Midea "U" 12,000 BTU is a standout. Just flat out performs. It requires regular cleaning, more so than others.

 

[JHZR2]

I wonder why it’s not cooling well then. And unless it’s like boiling a frog slowly, it seems like it was abrupt in terms of changes. I need to put a thermistor on the coil, and a thermometer in the air outlet. Probably need to clean the exterior coil well. Ugh.

 

[Cujet]

I wonder why it’s not cooling well then. And unless it’s like boiling a frog slowly, it seems like it was abrupt in terms of changes. I need to put a thermistor on the coil, and a thermometer in the air outlet. Probably need to clean the exterior coil well. Ugh.

It does seem like some real troubleshooting is in order. If you can get a low side gauge on it, that will be informative. But zero cooling suddenly could be a compressor reed valve failure( crack) (if it employs them), expansion valve issue or charge issue

 

[JHZR2]

It does seem like some real troubleshooting is in order. If you can get a low side gauge on it, that will be informative. But zero cooling suddenly could be a compressor reed valve failure( crack) (if it employs them), expansion valve issue or charge issue

I’m thinking it must be a valve issue.

Here’s the setup:

When it turns on the compressor runs. And it gets so hot I can’t touch it. But the lines don’t get hot or cold. Only this tiny coiled line gets ice cold.

The two little ones get ice cold and the big one does nothing.

 

[walterjay]

It appears you are low on refrigerant when you see that.

 

[JHZR2]

It appears you are low on refrigerant when you see that.

I think you’re right. Those two small lines are the liquid feed, the big one at the top was the return. The lines had been rubbing and when I messed with it a bit, I started to hear a real leak. I guess it was less than a pinhole, until I touched it.

Going to get the same model to slide in. While I’d like to install a three zone mini split, a 24k+ unit is $$$ and we don’t really run them enough to justify.

 

[Nukeman7]

It is interesting that a Freidrich window AC unit uses a Samsung compressor.