HVAC guy says my Ductwork is to small

[robertc65]

My new house (built in 1997) has a Goodman HVAC unit. Gas Furnace with of course AC unit outside. I have been in the house for only a month and the unit has failed twice. The control panel in the furnace has been replaced twice. I had another tech come out to give me a second opinion and was told that my supply ductwork was wat to small for my unit. He suggested replacing the Goodman with a smaller unit for the 1st floor only and installing a heat pump in the attic for the 2nd floor. 12K is too much for me to spend as the system seems to cool just fine. I have not had a chace to experience the heat yet. The tech said he would not even replace my system without addressing the duct size issue because the system would fail due to over heating. He also said that since the air moves so fast past the coil that the system will not dehumidify properly. I want to replace the whole unit soon just to start fresh. Should I get another opinion or is duct work that is to small really a show stopper.

Thanks

Rob

[dash]

From your previous posts,do you now heat the basement?That would get rid of some "excess " air.


I'd get someone who can test the static,and is very familar with Man. J and D,sizing and duct design.

Call around and ask for this,and you'll likely find very few will be interested,those are the ones you want to talk to.

[robertc65]

I currently have only one register in the basement going into my office. The rest of the basement will be finished in a few months so I will need a few additional registers at that point.

What is J and D duct design? I'd like to have some clue when I call around.

[dash]

Man. J is load calculation(size system),including the cfms (air flow) needed for each room in the home.


Man.D is to design(size correctly) all the ducts ,so each room will get the cfms needed to maintain the temperature evenly.

Both are products of ACCA,you might want to vist there website.

Static is thre resistance of the duct system to air flow,Ask to have the ESP,External Static Pressure of the duct system ,tested and compared to the furnace mfrs.. fan data chart.

High ESP,will give you lower than required cfms,which will shorten the life of your system,and cost more to operate.

[coco]

what size duct? how many heats?

[RoBoTeq]

We are accused many times of having a lot of balls on this forum, but none of us have crystal ones. What is size of the house? The furnace? The condenser? The ducts?

Here's how it works; you give us information and we can give you answers.