I have a 2 year old house with a carrier infinity system, gas heat, 21 seer 5 ton AC unit, humidifier, and ERV. The house was spray foamed and the attic insulation was increased. I'm not convinced the builder did a proper manual J with the changes I made to the energy package and the floor plan.
The equipment has had several installation shortfalls:
-Refrigerant drier installed backwards
-network interface wired improperly causing ERN to not function
-humidifier not tied into system properly to run on Infinity thermostat
-heat shrouding installed improperly causing unit to run in high heat mode ALL the time
-Lots of line noise (i think a 7/8 in line was installed and the instructions show the line should be 1 1/8"
-consistant heating/cooling differenc of 3-8 degrees in master suite.
I have dealt with the builder installer on several occasions and most of this has been remedied. I am in the process of finishing out my basement and need to expand my ductwork to include this area. I have had 4 separate contractors come in and give me 4 separate completely different diagnosis and repair of the unbalanced airflow problems.
For the heating/cooling inbalance, the builder contractor added another trunk duct to take off the esisting finished basement feeds, then did nothing to the old trunk. I am convinced this, along with a lack of proper supply and mismanaged return to the master suite is where some of my problems lie.
While dealing with the builder installer, I had asked on several occasions to see the manual J calculations and duct design for my house, they were not willing to show me this information. After speaking to the last contractor (who was willing do do their own manual J, but they were still off the mark on square footage) I went to the county and got a copy of the manual j that the builder supplied the building department. Their plans did not look anything like what was put in my house.
The last contractor I spoke with said the AC unit was oversized by 2 tons, even if you include the unfinished basement space. No other contractor has said the ac unit was too big (consequentally, none of them had done manual j's on their own either)
Other contractors have said the return is over sized, some say it's undersized. I have done my own calculations using software and it seems like 5 tons is the correct size.
I am stalling my basement project until I get this sorted out.
I have not gone back to the builder yet to address these issues because I have not gotten two contractors to agree on a fix to the problem. I also have no confidence in the builders contractor to do the work so whoever gives me the most logical fix, I will insist the builder sub it out to that contractor.
What steps should I be doing at this point? Inlist an hvac engineer?