Mini split repair
 

My bedroom mini split is not cooling like the others I have same brand same BTU.
I started to notice it last week and did some testing. The outside fan was running I could hear the compressor coming on. If I turned down the thermostat enough it would put out 64 deg air the other ones would put out 40 deg air.
Today it is 74 in my bedroom and I have it set to 67 it is putting out 68 deg air. It is getting worse each day. It turns up the indoor fan knowing it needs to work harder to cool off the room.

Reading issues on the net my gut tells me maybe one of the flare fitting is leaking. What the best way to test this.

I still have nitrogen to pressure test it and I can order Freon off eBay to recharge it.

There are many ways to do leak checking, and the best way depends on who you ask.

For my experiments, I have used bubble blowing soap, bubble bath liquid, scrubbing bubbles bathroom cleaner, and softsoap hand cleaner gel. Anything that will stick to the suspect surface well (more than a minute or two without running off) and form long-lasting bubbles or suds will work. Dead reckoning approach: bubbles sighted confirms a leak.

If this condition slowly occurred, the best approach is to look for signs of oil that leaked out with the refrigerant. This is best done with an ultraviolet (black) light source. If you smeared oil or some kind of sealer on your fittings during assembly, it may or may not look the same as fresh oil. UV dye can be injected into the system easily, and is available at supply houses everywhere. This makes detection much easier, as even a tiny amount of oil will shine brightly under the UV light. I have used this method in automotive systems, both to spot refrigerant and engine oil leaks.

Another thing to consider is this: when refrigerant leaks out of the system, conditions inside the loop become favorable for contamination. If enough charge is lost, the low side will operate at less that atmospheric pressure, encouraging ingress of non-condensible gases and moisture. If only SOME refrigerant leaks out, compressor discharge temperature can rise to levels that will "crack" the oil into smaller molecules. One of these molecules is water. If more than a few PPM of moisture gets into the system (especially with R-410), this is cause enough to evacuate, drain the oil, and start over with brand new refrigerant and oil.

I have had better luck with these "caveman/luddite" methods than with modern, electronic sniffers. I have heard both ways about them: some swear by them, some say they will only detect larger leaks reliably.

I love the UV dye idea.
Is this what is needed?
Amazon.com: R410A Refrigerant With UV Dye Added - 1.8 Lb Disposable Small Cylinder: Automotive
It seems pricey.

I was thinking about ordering this.
410A R410A Refrigerant 25lb Tank SEALED Lowest Price on eBay Same Day Shipping | eBay

I was planning on vacuuming it out and putting in new Freon. How do you do the oil is it necessary?

How about a leak detector?
Freon Leak Detector Refrigerant Halogen R134a R410A R22A Bag Air Condition HVAC | eBay

SODIAL(R) Freon Automatic Halogen Leak Detector R134a R410a R22a Air Conditioning HVAC - - Amazon.com

Do these things really work? :confused:

This was the R410A size I ordered.. Still have a lot of left over..
Easy to Use R410a cylinder

My outdoor unit that the pin-hole, was exposed to air a long time..
I pumped in CO2, so I could braze the leak. Then, when I tested it,
it seemed to work okay.. (Compared to the new replacement unit).

I just vacuumed it and loaded it with R410a, without adding any oil..

I think there was still a lot of oil in the crankcase..
http://ecorenovator.org/forum/geothe...r-project.html
Then 4.5 years later, a power surge killed the main board.. :(

I ordered the leak tester but I will still use the bubble test to finalize the check and look for oil as suggested.
I ordered the 25 lbs. R410A the smaller one was $100 shipped I got 15 more pounds for $15 more.
There may be other projects down the road.
I have your project bookmarked. Thanks for the help!

Can anyone recommend a flaring tool that is cost effective and still works good.

This one http://www.amazon.com/Flaring-Swagin...rch_detailpage has done me good. Flaring even 1/4" is easy.

My old brain is asking me.. Is it 45 or 37 degrees for the R410a flares??
I 'think' my flare tool was a 45.. Can't remember.. If you need me to look, I will find it..

45 deg flares is what I am seeing.
I did not run the mini split last night and today I just took off the line set cover. I inspected all the flare fittings.
The small line at the top had some oil around it. I tightened this fitting some and turned on AC. I did a bubble test. I didn’t not see any bubbles but this line froze up very quickly. Is that normal?

The small line is frosted up on the outside unit also. I checked the other two units and that line is not frosted up at all.

It is putting out about 70 deg air. Do you think it is ok to run it or should I shut it down until the new Freon gets here?

your getting frost on the small line?

sounds like something is reversed to me