Balancing issue or something else?

[dvzzz]

Dear All, need help to understand the issue. Looking to buy a house with two systems. Attic unit cools the second floor. House is 5 years old, but my problem is that master bedroom is not cooling enough, registers in the master bedroom show 56 degrees while all other rooms' registers are between 40-50 degrees. HVAC unit is right above the master bedroom and ducts are short to the registers in the master room. Seller is saying "works as designed" but it beats me why he refuses to air balance them. I do not have any equipment to measure air pressure and speed, but if I put my hand to the register pressure is much less than in other rooms. Could there be something else that Seller is hiding? I called an only available in my area HVAC-Talk contractor from the HVAC-Talk Map and his phone is not even active anymore. Others are 30+ miles away and unlikely to roll to this place. I need help in Mundelein, Illinois so if I can find reputable tech with necessary quality equipment that would be great.

[Big Unit]

Balancing issue or just undersized duct to that room. Worst case is it's an undersized duct and if it's a short run like you say nothing that any mechanical contractor or even yourself can't fix.

[XcelTech]

Often being the first drop off the system is a bad thing.

It is likely your bedroom duct is either the first of several drops on a main trunk or it is the smallest of all the trunks coming directly from the plenum. In both cases, air movement is much like electricity and water, when given a choice it will take the path of least resistance. This means if your a small duct of 3 or 4 the air is gonna choose the bigger ducts until the static pressure builds up enough to force the air out.

As you mentioned this is an air balance issue.

Another common problem is improperly sized duct work that does not narrow soon or often enough causing not only the air to bypass your vent but it will in some cases suck air into the vent from your room.

If your registers have adjustable grills close all the grills and see if the pressure to your room increases. then adjust the grills until you get a good balance in your room and the others. Then call your contractor and jump down his throat and tell him if he wont fix it he needs to pay for someone who will.

An Airbalance should be done anytime there is a major change like replacing the fan, furnace reduction or enlargement of a room,....and so on.

[dvzzz]

Thanks so much, I hope I can find a local contractor who can do air balance properly, do not want waste money for trial and error. Seller does not want to fix, he knows balancing is costly or at least instrument-based balancing is.

[XcelTech]

Illinois is full of union sheet metals workers call your local and see what they got.