I've been having troubles with a LENNOX split system for awhile.
It began when I went to do a site survey for a new customer. Their split heat pump AHU in their receiving area had been hit with a forklift and there was a leak somewhere in the system that had loosed all the refrigerant.
Anyway, I fix all the ductwork damage, find the leak in the CU and repair that, finish the job and get it back online.
The compressor takes a nose dive and dead shorts shortly after startup. I get the compressor replaced a little bit later, do the nitrogen purge during my brazing, a new Bi-Flo drier and a triple evacuation with dry nitrogen breaks between evacs.
Two, three weeks later it quits working. I go out there and find that there is a restriction at the TEV. I order a replacement then do the deed later. It's a threaded mount so replacement is easy. I still do the new filter drier and triple evac and start it up. My suction pressure takes a nose dive into a vacuum. I start looking deeper and eventually find that there is a strainer in the liquid tubing that is completely blocked up as well. I cut, snatch and sweat and do the triple evac again, start it up and everything is great, it's doing some excellent cooling.
Two weeks later it quits again.
I go back out and find that there is another restriction in the system.
I flip it through heat cycle a few times in a lame attempt to dislodge the restriction and trap it in the filter drier. No good, it's stopped up badly.
Today, our senior tech goes out there and does his search. He finds that someone had used that ACR Stop Leak at some point in the past and when I changed out the compressor the activities I went through caused whatever had been left in the system after the rest got taken out with the old compressor to get knocked loose and get stuck in the new TEV I installed a few weeks ago and, caused me no end of skull seat and head bashing against the wall.
Now we just have to do a rather complete and total system cleanup to get all of that crud out of there so that it doesn't suffer more shutdowns from restrictions.
I can guarantee I will never use or recommend the use of ACR Stop Leak because that garbage is dangerous!