AC running longer and cooling less

[mcragan]

I built a house two years ago and installed a Goodman furnace and condenser. I believe it is a 3-ton unit with a 45 foot line set.

The first year it seemed to cool great. Last summer is started running longer and longer to keep the house cool, eventually running all day without keeping house at the thermostat setting of 80F.

I called an HVAC professional to look at the unit. He came out, hooked up his gauges, said the coolant was okay but could use a little more, and added a couple of psi of coolant to the system and stood around smoking cigarettes and watching his thermometer for an hour before charging me $150.

Performance after his visit did not change at all. The weather started cooling off and I put off any more action until this year.

The system still cools but is not nearly as good as the first year the system was installed. My in-laws have a home next door with the exact same floor plan and HVAC system and it works much better than mine. Their AC will keep the house cool and still cycle on even the hottest days.

I don't want to call another HVAC Tech out if he is just going to do the same thing as the last one.

What else could be the cause of the reduced efficiency? The line from the condenser feels cool when the system is running. The compressor does come on. I have a quick read thermometer and a gauge set to check the system temps and pressures if I need to.

 

[geo]

I heard 2 good things about that tech first is he had a thermometer out . hopefully a clamp on. second is that he waited around . After adding or subtracting you should wait 10 min and do just that let the temp and pressures equilize. So I dont think you got a total mook but he did obviosly miss something. has your system ben serviced ? Did he talk about the high likely hood of a leak? do you change your own filter? did he check your filter and for a clean evap coil before chargeing the system? I wouldnt hesatate to call the company back again the guy at least did some stuff right . You paid for a problem to be fixed and it wasnt , that doesnt mean you get you money back because you very well might have needed the refrigerent(not a bad price) but you should at least be credited the diagnostic charge to locate any additional problems considering that should have ben done before adding to the system

 

[glennjanie]

Welcome Matt:
The cardinal rule of A/C service is "CLEAN first, GAS last". If your condenser coil is dirty or full of grass clippings the system can't preform to maximum efficiency. Adding refrigerant to a dirty system is self-defeating and the worst thing a service man could tell me is, "It just needed a little gas".
The refrigerant runs in an enclosed system, changing from liquid to gas and back to liquid again. It doesn't get used up, loose its efficiency (wear out), or evaporate away unless there is a leak. Therefore, if you tell me "it needed a little gas", I want to know where the leak is and what he did to repair it.
Another problem we sometimes see is too much shrubbery too closee to the condensing unit. You may want to check that out too.
Glenn