Question on Carrier Infinity System

[kpt_krunch]

Hi all

Just moved into my new home a month ago and some of you may recall I went with a major upgrade - a Carrier MVB120 with Infinity Zone control - 4 zones total for a 2808 (above grade - close to 4000 including basement) sq.foot home.

My question is this - over the past few weeks it's been very hot here. I don't have A/C yet (still arguing with the wife on that one) but was trying to use the fan option to circulate the air in the house.

Problem is, on the high setting, the fan really doesn't blow all that hard anywhere. I tried setting all the zones, and each individual zone separately, and nothing. I mean, it blows, but not that much. Every once in a while it does kick in up a notch or two for a few minutes, then it goes back to a low setting it seems.

When the furnace kicks in to blow heat, it pumps air out just fine (yes - up here in Canada you can be screaming for A/C one day and your furnace can be on the next), like my original Infinity did (MVP) in my old house.

Now, is this normal for the Carrier Infinity MVB to do this, or does something need to be changed on the control board in my furnace?

Thanks all!

[duct dr]

The infinity system uses a variable speed blower. When you use the fan only to circulate air it won't run at 100%, it's not designed to. Also when you have a zone system, there's a bypass damper that's installed between the plennum and return. that damper has a counter balance on it that allows it to open and close using air pressure. I.E. with only one or two zones open, the bypass damper will open more than if all zones are open. If the damper opens too easily, it will bypass too much air resulting in little or no air at the registers. A contractor needs to do a static pressure test and adjust the counter balance accordingly.

[kpt_krunch]

thanks very much for the informaton Duct Dr!. I have to call them in to clamp my hose properly as they didn't do it, and I'll ask them to do the static pressure test at the same time (I can clamp it myself - but I paid a lot of money for this house and the system as well, may as well make them do it).

Thanks again, much appreciated!

[desol]

I could be wrong on this system...but most variable speed furnaces have different ramping profiles for cooling and heating. Have a look in your manual and see if you can up the cooling speed a little. There are most likely dip switches and a legend in the manual. Also...when your running your blower fan continuous...your constantly pulling in warm air from outside via the fresh air intake(not combustion)at 500 cfm that amounts to ALOT of warm air in....after a while...

you could always have a hoyme damper installed in the fresh air...so it would close during cooling operation(to prevent warm air coming in)...and open during heating operation(to allow fresh air in).
Hoyme dampers also increase the effectivness of the central air system...stopping warm air coming in...while in cooling operation. ie: Why would you want to pull in hot air from outside while your running your air conditioning?

[Edited by desol on 07-13-2006 at 11:48 PM]

[4l530]

I have installed and serviced several Infinity systems. I have not as of yet seen one that draws in outdoor air... ERV equipped maybe?
Would not advise to start playing around with the dipswitches, that's what a service tech is for.

[york_hvac]

Infinity does not need a bypass damper, has the VS blower, automaticly compensates for the dampers changing during heating and cooling cycles, so it is not needed.

[keepitsimplestupid]

I believe that the MVB/Infinity system generally frowns on bypass dampers.

Although I haven't tried it, but you should set your tstat to cool and tell it, or preferably have your installer tell it, that has an AC attached (even though it doesn't) with a higher capacity. It will then likely select a higher fan speed. A guess. Don't have the inclination to try it, though.

There might be some furnace control board options too.

[york_hvac]

Originally posted by desol
I could be wrong on this system...but most variable speed furnaces have different ramping profiles for cooling and heating. Have a look in your manual and see if you can up the cooling speed a little. There are most likely dip switches and a legend in the manual. Also...when your running your blower fan continuous...your constantly pulling in warm air from outside via the fresh air intake(not combustion)at 500 cfm that amounts to ALOT of warm air in....after a while...

you could always have a hoyme damper installed in the fresh air...so it would close during cooling operation(to prevent warm air coming in)...and open during heating operation(to allow fresh air in).
Hoyme dampers also increase the effectivness of the central air system...stopping warm air coming in...while in cooling operation. ie: Why would you want to pull in hot air from outside while your running your air conditioning?

[Edited by desol on 07-13-2006 at 11:48 PM]

I see that you are new, you may have never worked on a system like this. The Infinity System is very different from other systems out there, read more bellow:

http://www.commercial.carrier.com/commercial/hvac/product_description/0,,CLI1_DIV41_LNK8163_ETI4926_PRD1141_SIT12,00.htm l

I don't think that he would have a fresh air duct, this is a 90%+ efficiency furnace, direct vented to the outside.

[desol]

Thanks for the link. :) No i haven't worked on a system like this before...looks sweet tho!

Still...you would think you could adjust the fan profiles...and you would still need fresh air(air exchange) coming into a sealed house...as far as i know you ALWAYS need some sort of fresh air coming in to replenish sealed construction.
but i don't mean combustion air......fresh air.
I'm 3rd year Gasfitter 1st class...

[Edited by desol on 07-14-2006 at 12:25 AM]

[imperix]

if you want more circulation air go outside pull condenser disconnect out turn it on cool you should get more airflow

[docholiday]

Bottom line is no fan is going to cool your home. It will merely move warm air around. In fact, if nothing else you get motor heat added.

Break down and get the cooling installed.

[dash]

Originally posted by docholiday
Bottom line is no fan is going to cool your home. It will merely move warm air around. In fact, if nothing else you get motor heat added.

Break down and get the cooling installed.



Yeah,and go with two stage cooling !!!LOL!!



Seriously ,you'll love two stage,and it's the best way to go with your zoning system.