Carrier Infinity ICS Blower question

[rustwood]

Hello -

Does the blower on the Infinity ICS furnace operate like a 3 speed in normal operation or does the blower speed 'continuously' change when it is actively heating? Their web site it lists it as a variable speed fan, but on my ICS if you take the blower off of auto you can choose low, medium, or high. It is capable of adjusting those 3 speeds to whatever CFM are appropriate for the duct work and other system settings, but you only get to choose from whatever those 3 rates are set to. I am just curious as to whether the system uses those same 3 levels when it is actively heating or if it blows at whatever CFM it 'thinks' it needs at the time.

Reps for other brands that also have variable speed blowers had told me that once their furnaces are adjusted, they will only blow at one of 2 speeds. I am wondering if the ICS is the same except that it is 3 speeds. Either way it seems to do the job well, I just think Carrier may be a little loose with the term modulating (seems like 3 stages to me) and wonder if that is also partially true of the 'variable' speed blower.

Also, when you compare models on the Carrier web site it says all of them have "Media Filter Cabinet Included" - is that the internal slot for a 1" filter or is that an external cabinet?

Thanks.

[second opinion]

Hello -

Does the blower on the Infinity ICS furnace operate like a 3 speed in normal operation or does the blower speed 'continuously' change when it is actively heating? Their web site it lists it as a variable speed fan, but on my ICS if you take the blower off of auto you can choose low, medium, or high. It is capable of adjusting those 3 speeds to whatever CFM are appropriate for the duct work and other system settings, but you only get to choose from whatever those 3 rates are set to. I am just curious as to whether the system uses those same 3 levels when it is actively heating or if it blows at whatever CFM it 'thinks' it needs at the time.

Reps for other brands that also have variable speed blowers had told me that once their furnaces are adjusted, they will only blow at one of 2 speeds. I am wondering if the ICS is the same except that it is 3 speeds. Either way it seems to do the job well, I just think Carrier may be a little loose with the term modulating (seems like 3 stages to me) and wonder if that is also partially true of the 'variable' speed blower.

Also, when you compare models on the Carrier web site it says all of them have "Media Filter Cabinet Included" - is that the internal slot for a 1" filter or is that an external cabinet?

Thanks.

From your controller you can select a continuous fan speed, when the controller gives a heating or cooling command for first or second stage the fan will adjust to the speed being requested.


The filter cabinet is a container of its own.

[rustwood]

From your controller you can select a continuous fan speed, when the controller gives a heating or cooling command for first or second stage the fan will adjust to the speed being requested.

Thanks for your response, but I don't think I follow what you are saying. I know that I can select one of the 3 continuous fan speeds. What I want to know is does the ICS select from one of those same 3 fan speeds when it is actively heating or does it literally adjust the fan speed to whatever CFM/RPM value it 'thinks' is best at any given time? Is that what you are saying or are you just saying that it will override the continuous fan setting when it 'needs' one of the other 2 preset blower settings for active heating?

Also, does the included external filter cabinet accept any 2 or 4" filters or is it just for 1" filters?

[skippedover]

What you may be missing is that there are 2 levels of settings at the user interface. One level is for the homeowner and the other is for service techs to make adjustments that the HO shouldn't try to make. The service tech can set the CFM requirement for continuous operation and from that base, the HO can select low, medium or high fan, up to the CFM rating set by the installer. But the ECM motor is a true variable speed motor. What that means in operation is that the computer will continuously run the algorithms to maintain optimum fan speed to move the CFMs needed for proper equipment operation. The User Interface (thermostat) knows what size equipment it's communicating with because of the model number. In turn, it knows how many CFM are needed to meet the manufacturer's specs for that size equipment. So if, for example, your air filter gets dirty, the fan will speed up to compensate for what would be reduced airflow otherwise. Likewise if you were to close a damper or two, the motor will change speed to again, make sure the proper CFMs are moving through the equipment. The UI also tests the system every 24-hrs. to determine the airflow and static pressures of the distribution system. Many people don't realize it does that test because it happens during the midday when most folks are gainfully employed or out of the house otherwise on the weekends. So they rarely hear the increase blower speed test, which only lasts for a couple of minutes.

[nubbin]

The furnace is like 3 different machines. The continous ventalation mode has 3 preset speeds. The cooling and heating modes each has its own a ramp-up, top speed, and a ramp-down profiles. The cooling will move more air at top speed.

The external filter cabinet comes in so many flavors, manufactures, etc. Check with the installer or ask your preventive maintenance tech when he does your seasonal check-up.

[catmanacman]

the carrier filter rack comes in a box that needs to be assembled and installed to the base of the furnace and takes a ez flex filter only avalible from carrier and they are very proud of it

[mrteboe]

The filter cabnets come in 16x25 20x25 and 24x25 all 4 in thick they also offer elec filters

[rustwood]

Thanks for the replies. It's good to hear that there is more going on with the blower than just switching between those 3 speeds. Of course whatever it does, it seems to give good results so that is all that really matters.

I did not get a 4" cabinet with my system, but after looking at it, I suspect that might have been because there isn't enough room to fit it in without 'moving' the return duct over 2 or 3 inches. Not impossible, but perhaps more work than the installer had in mind. I should have asked for a 4" filter cabinet to be included/listed on the quote. We had talked about it and I mentioned that the web site said one was included, but it wasn't actually on my quote. Live and learn I guess.

[york_hvac]

Hi, I have a 58MVB Furnace similar to yours, it is truly variable speed, but like everyone else has said, there are profiles for when it changes speed. If you want a detailed explanation, look at my (long) post here:
http://hvac-talk.com/vbb/showthread.php?t=115371&page=5

The system does come with a media cabinet, but it is up to what was in your contract as to whether or not it is installed. When my house was built, we asked them to put it in, since it came with the furnace, so we had technically already paid for it. So there it sat for a few months, in its package. It can be set up for 1" filters or 4" media filters:


But for some reason, they removed it, and installed a Honeywell F100 cabinet instead: