Question on register sizes

[jeepgrady]

I've been having numerous issues with my heat pump which I have posted in other threads during the past year. You guys have given me a wealth of assistance for which I am very thankful.

The majority of the problems were caused by a totally lousy initial installation coupled with the clear ineptitude of the servicing personnel that were sent to correct my deficiencies.

This was a new home built in 2007. Most of my problems have been addressed, finally.

I have obtained the HVAC Mechanical plans for my home and have a question. The plans list the ductwork coming off the main trunk showing the sizing of the supply registers. Well I have discovered that there are seven registers that the plans called for 8 inch registers , yet they installed 6 inches. There are also two registers that should be 4 inches, yet they installed 6 inches.

What affect will these incorrect size registers cause on the overall operating of the system?

Thank you once again for your assistance.

[heaterman]

A lot depends on the required CFM for each run coupled with the CFM capacity of each register. The CFM of each run should be on your plans so all you really need to know is the capacity of the registers. I am assuming that these are round ceiling registers, are there balancing dampers associated with the registers as well?

[jeepgrady]

These are the rectangular registers. Based on the plans the 4 in. register handles up to 60 cfm. The 6 in. up to 100 and the 8 in. up to 150.

The two that are oversized call for cfm that is lower than the requirement for that size, however, the registers that are undersized call for cfms higher than what the sized register should handle.

I also believe that all of the registers can be balanced.

[heaterman]

If the registers are not noisy and temperatures are balanced I would go with no harm no foul. The oversized registers are of no importance.

[jeepgrady]

I'm more concerned with the undersized registers. Should I be?

[jeepgrady]

Anyone else?

[Shophound]

I'm not familiar with your post history, so excuse my questions. Are you having comfort problems in the rooms where you are suspect of the register and duct sizing? Do you have pictures of your installation that can be posted (that always stirs up a lot of discussion!)? What problems have you had that have been resolved, and what remain that continues to be bothersome?

[jeepgrady]

No pictures of install. I've had too many issues starting from the original installation to mention at this time. I'm, not exagerating when I say that I've had somewhere around 50 service calls in the almost two years I've been in the house. Some issues were: freon leak, long duct runs, aux heat problems, defrost board, numerous wiring issues, tornado like effect when small zones were running by themselves, tvx valves, insufficient heating and cooling, and on and on. I started with a v/s speed air handler and that was even switch out to a single speed.

I must say that the majority of issues were caused by or made worse by the lack of hvac knowledge on the business. Even had Lennox here on two separate occasions. At this stage I can honestly say that by me reading all of the installation and service manuals that I could obtain that I have more knowledge about my own system than many of the techs that have been sent out. Now, that is really a pathetic statement, but true.

The only individual that seemed to know what was going on was someone I met on this forum that came over to my home last winter. Within about an hour, he was able to provide me with an extensive list of problems he saw in the a/h installation. The problem is that since the home is under warranty, the developer will not let me deal directly with this individual since they have no agreement with him.

Anyway, at this stage there are still some issues remaining. Some of them are: no electric back-up during defrost, still a tremendous amount of air from the small zones when running by themselves, some vents are not producing the required amount of air per the plan.

I'm just trying to get an idea how big an issue, if any if the mechanical plans call for eight inch registers vs. six inch.

Any help would be appreciated.

[dash]

Undersized grilles would add to noise,are they in the rooms where noise is an issue?

They might even reduce airflow a little ,any rooms that are "off" in temperature?

Oversized could affect the temperature within the room,meaning part of the room farthest from the grille doen't get enough air flow,causing a different temperature or contributing to drafts.Any of these apply??

Who drew the plans?Here in Florida it would be the installing contractor,point is ,are they even correct??

[jeepgrady]

The biggest noise problem is in the smaller zones, however, this has been attributed to the installer running a 10" duct in the by-pass vs. a 12". This will be addressed. I'm not concerned with the two that are oversized as far as comfort goes.

The plans were drawn up by an engineering firm. My developer is one of the big boys in the industry that builds or used to build hundreds of homes a year.

So, in a nutshell, I guess what you are saying is that assuming that correcting the bypass duct will fix the excessive noise, I shouldn't be concerned, right?