Rheem gas furnace and central A/C, 2004 manufacture date, installed 2005 new construction house, put into service (started using) 2006 when we bought the place. I don't know the tonnage but house is typical 1.5 story 2250 sq ft, brick 1st story, siding for the upper 1/2 story. Dual zone by diverter in the supply plenum.
So the unit has been virtually trouble free and serviced every other year with me changing filters approx every 9 months (20x25x5 Honeywell). Has some kind of anti-bacterial ultravoilet light bulb thingy installed in the return plenum not sure what it's called, supposed to help against [censored] in your air I guess.
Anyhow, had the recent heat and humidity wave last week and week before, highs mid 90's high humidity w/ heat index (how hot it feels) in the 100-105 range. The unit did fine. Thermostat @ 77 lower zone 79 upper (no one upstairs anymore) during day, down to 74/79 evenings and overnight. Unit pulled the temp on lower zone to 74 without much trouble or excessive running through the heat wave.
But, over this past weekend, after a front came in and heat wave gone, temps more mild, the unit inexplicably took a dump and stopped cooling well, would run and run struggling to bring lower zone to 75 and wouldn't get it any lower. Air out of registers barely cool. And the kicker: when the unit was running I could hear the refrigerant in the lines where they enter the evap coil air handler box making the sounds they would normally only make at shut down when pressure is equalizing-- gurgling sound. To me, and I know only enough about HVAC to screw something up, that hinted at a low charge i.e. a leak. Next door neighbor changed cable providers and they marked underground lines recently in between our houses and my first thought was maybe they tripped and fell into my condensor unit and triggered a leak. But it looked undisturbed.
Called out the HVAC contractor. Now for the kicker: He used his electronic sniffer and had a time finding any significant leaks !! Said he got some really weak indications in the air handler at the evap coil, but found the unit real low on charge. forget the figures he said but said it was only producing a 10 degree drop on the coil it was so low. Charged it to get me going, but the bad news is the unit uses R22 and the materials charge alone for the amount he had to put in was $238. The invoice looks like it says R100 though, but he did say it was labeled for R22.
So it's cooling like a champ now (shouldn't have said that probably...) but we were both scratching our heads on how it could lose that much Freon in that short time span and not be indicating a larger leak somewhere.
Anyhow, he said the evap coil was clean but did show a level of corrosion expected on a unit in service almost 12 yrs. Said should consider just replacing the entire system since install of a new evap coil and the necessary capture of existing refrigerant plus the cost to recharge the entire system with the old stuff might represent sinking too much expense into an old system. Said he'd have their estimator give me a call.
I'll probably collect several estimates.
I do plan to sell the place soon, next year or so, so I suppose a new furnace and air cond system might help it on the market.
But [removed] anyhow...