67-68 is very poor supply temp...you should be expecting a Delta T of 15-20 degrees. That is difference between supply temp and return temp. check your return filter. Also your refrigerant charge should be checked and possible leak investigated.

TD

Are the maintenance people HVAC technicians? How are they determining the "pressures check out"? Your electric bill is high because the AC is operating inefficiently. Most the likely the system was under charged when the new air handler was installed.

Thank you both for answering...here's some additional info:

TD: The thermostat is 3 feet away from the door to the air handler and it's registering about 73-74 at the time that I'm getting 67-68 at the supply. The filter is just about a month old (I change it every 4-5 weeks). I believe the refrigerant was checked when the coils were replaced.

Mike: I'm not sure what kind of certification they have but they themselves are the ones that installed the new coils and blower last month, as well as check the pressures with the Red, Blue & Yellow hoses that I see AC companies hookup outside. The guy today mentioned that the pressure is "135" which he claims is where it should be. Based on what I read/understand online, 135 PSI is the minimum pressure on the high side based on an ambient temperature of 65 degrees (which it's currently about 85 degrees here today) so not sure if he read it wrong or if I'm understanding this wrong...

"I noticed a significant increase in air flow coming out of the vents, ..."

Faster blower speed, higher airflow rate, will reduce the temperature drop, but shouldn't be as much as you're seeing.

^^^^^ This is true but you should still have a larger temperature differential (return - supply) from your system. Something doesn't sound right. What is the model of your air handler, coil, and condenser?

Non-condensables in the system may be the problem. Non condensables are gases like oxygen and nitrogen that were not evacuated from the system after replacing the coil. They will congregate in the condenser lowering the efficiency because refrigerant doesn't completely condense. There is also the chance the the expansion valve with the coil they installed wasn't compatible but I'm going with Non-condenables for $100.

Everything will appear somewhat normal and not the easiest to troubleshoot, but if maintenance fudged up the repair process I'm sure they won't know how to determine the presence of Non-condensalbes.

Based on what I read/understand online, 135 PSI is the minimum pressure on the high side based on an ambient temperature of 65 degrees (which it's currently about 85 degrees here today).

That's no where near right. High side pressure is always higher than 135 PSI. Even if the machine is off, high side pressure is higher than that.

Differences in refrigerant. I suspect this is probably R410a, but you don't specify this.

That said there's more to it than just reading a pressure comparing it to ambient temp. Apartment maintenance people are some of the lowest paid people there are in HVAC realm. You don't get skill with low pay. Anyone can do HVAC, That doesn't mean *by any stretch of the imagination* that they should.

It's not just knowing what you should do, it's also knowing *WHAT NOT TO DO*. Skill in a nutshell.

(I started my career in Apartment Maintenance over 25 years ago... lasted months there, just to get some experience under my belt find something else for more money. No one in their right mind would work apartment maintenance for long... which doesn't help you except exposes the shim sham operation of apartment complexes.)

So if you're in Apt. Maintenance dept. There's nothing wrong with that... but these are low paid positions (temporary and nearly always high turnover).

Given the unskilled conundrum you've got a fight on your hands because it already sounds like they're blowing you off multiple times already.

True, some apartment maintenance workers tend to be one step ahead of the law or started their training in prison maintenance, but the jobs usually included a free apartment and got them off the street. But the quality of maintenance people depends on the management company and I've seen some highly trained professionals with decades working for the same company, and well paid to $25/hr top scale in 2012. To be fair not many, well it was only one company but had thousands of units including high rises requiring training and competency tests to advance up the pay scale. I'm sure there are others.

I started working industrial maintenance 40 yrs ago on the 2nd shift witch gave me the opportunity to attend Texas State Technical College for HVAC full time for a year, and then worked mainly in commercial/industrial settings. With another two years of full time technical schooling in electrical and electronics I was ready to move up to the big companies witch paid for what you knew, not what you do. Hear that? ME beating my chest! BOOYAH!

My Carrier path was OK but feel I wasted my life and traced it back to the day I dropped out of Kentucky state university and moved to Texas. My true desire was to major in chemical AND electrical engineering, to save the planet with a sustainable energy source and be a hero. This was 1979, I was ahead of the curve, but I lacked the patience and intelligence to endure almost a decade of classroom training. I'm Still working on a energy source, almost have it and I only need another 40 years.