HVAC not working / TECH says its fine! HELP

[4eleric]

I recently came home from a weeks vacation. While gone i raised the temp to 85 degrees F and let the AC run. When i came home (4am) i turned the AC to 71. I have 2 AC systems (a larger downstairs / a smaller upstairs). The downstairs until quickly cooled the floor, the upstairs until had almost no airflow and did not cool.

Next day a HVAC repair guy came out, checked out the system, added coolant, and said it was fixed (i was at work / he dealt with my wife). I came home and the air flow prob was still there.

2 days later company came out again. Same thing - they couldnt find the problem. In fact he told me flow was as it should be and that i was wrong in thinking it was once fast. (*long sigh*) Additionally, the AC outdoor unit turned off for some reason and he had to come back and tinker with things to make it turn on again.

HVAC company's position is that there is no problem and its working fine.
My position is that the air flow is drastically reduced from what it was 1 week ago and that the outdoor unit turning off on its own has got to be indicative of a problem.

So far, changed air filters throughout the house. Changed batteries on thermostat, added coolant. The house is only 3 yrs old.

Does anyone have ANY idea what could be going on?

THANKS!!

[HayZee518]

both condensers are mounted outside - correct? if the tech added freon to both or either unit there is a leak somewhere because the freon system is a closed circuit. unless there is a leak, there is no way the freon could get low. it doesn't break down from use, it doesn't change state from one week to another. lines to the evaporator should be one continuous length. lines from the evaporator should be one continuous length. lines that are spliced should be brazed, and not be relied upon using flare connectors. the way they are brazed is one tubing is expanded so the other tubing fits into the expanded end and they are silver brazed together. the high pressure line and suction line are routed "together" back to the compressor/condenser unit. the suction line [the bigger line] is insulated along its entire length using neoprene foam tubing. the boiling point of freon - either r-12 or r-22 is around minus 28 degrees so exposed copper lines will freeze forming ice but will not effect the freon inside. your tech might need to check all splices with an infrared leak tester or a propane tank reaction plate tester. not many techs want to take the time to check splices, but they have to if they are make good a service call.

[4eleric]

I will print that out and make sure they do what you described!!!

Thanks a ton!

[HandymanTrainer]

One more thing...if filter maintenance was sketchy and the indoor coil was dirty, the coil could easily freeze, thereby causing incorrect readings on the gauges. Less experienced technicians automatically assume the unit needs freon and over charge the unit. If the unit is equipped with an auto resetting high limit switch, the unit will shut off and back on regardless of the t-stat.

HandymanTrainer