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  1. #1
    Join Date
    Jun 2009

    Carrier Infinity Air Purifier & Static Pressure Qs

    I have a Carrier Infinity System with the Air Purifier System in my new home (system started up in February). In the past few days I have started having the "System Malfunction" message display on my controller and the unit seems to stop cooling at times. I talked with my tech and he is unable to get out here yet (extremely busy right now), but he told me how to "reset" the system by turning the system off, turning the breakers off, then turning everything back on. That works temporarily, but then it eventually stops cooling again.

    I know this is not a DIY forum and I AM getting a tech out here sooner or later (I'm hoping he can get out here sooner!), but I'm just curious about a few things. One of the many faults that I am getting is "Excess Static Pressure Stagedown" (others are "Thermal Cutout in Low Stage", "Thermal Lockout in Low Stage", and "Control Fault"...I think the control fault is from when I kill the power based off the timestamp). I was wondering if I should be running the regular filters in my return still since I have the Air Purifier with Cartridge (I am right now). I just wasn't sure if this is adding the high static pressure. The static pressure is around .96-1.01 with the compressor running (drops to .77 with it off and just the fans running). I was messing around and seeing what happened if I removed some of the filters. If I removed the filters in the return, it dropped down to .89 or so with the compressor running, then I removed the air purifier cartridge and it dropped to around .72. From what I can tell, I should be replacing the cartridge once a year, but I'm guessing I should go ahead and replace it since it's new construction and there was alot of dust in the home.

    Any ideas where my problem is starting from? I'm going to still have the tech come out, but in the meantime I'm going to replace ALL of the filters (maybe leave the return filters out???). I've never dealt with a unit with the air purifier, so I'm not sure if that takes the place of the return filters, but I really wouldn't think so.

    I also thought it was strage that all of the faults came while the unit was running in low stage and not high stage, but I'm by no means a HVAC guy!

    Any thoughts or suggestions would be helpful. I've already gotten my faults to my tech, but he seemed a little stumped, so I'd like to have some suggestions for him if he can't find anything when he gets here.


  2. #2
    Join Date
    Aug 2004
    North Richland Hills, Texas
    Usually it is duct design issues that cause that...
    If more government is the answer, then it's a really stupid question.

  3. #3
    Join Date
    Jan 2004
    If those are your static pressure readings in low stage. WOW.

    Either your filters are plugged, or your duct is really undersized.
    Contractor locator map


    How many times must one fix something before it is fixed?

  4. #4
    Join Date
    Jul 2007
    Jacksonville, Fl
    If you have purifier, remove all other filters. The purifier filter is the only filter that should be used. Any other filters being used at the same time more than likely will cause high static pressure.

    Also your Thermostat controller should be set to media+EAC <tech can should have set that up and can verify it for you.

    Next how old is the purifier filter? This could be dirty and in need of replacement. We have replaced them as early as 6 months.
    If this is the case you can temporarily shut down the purifier and remove the purifier filter. Then you can use your other return filters in the mean time.

    It freezes or malfunctions in low speed since the air velocity may be reduced especially in dehumidification mode

    Another thing to check on the purifier, make sure when your air handler is running that the LED light is on.

    what is your model # of your inside air handler and outside unit?
    Carrier/Bryant has several different combination's of the FE air handler that can be matched. The Bigger the air handler the Better the SEER rating but with that the bigger the evap coil is and that will have a slighter restriction causing a tad bit more static pressure on the system.
    .89 is a little high but still ok. just remove your pre return filters.

  5. #5
    Join Date
    Jun 2009

    Thanks for the info. I'll try removing the other filters.

    Just for information purposes, I woke up this morning and the unit wasn't cooling, but the fans were still running. I checked the static pressure and it was between 1.14 and 1.19!!! It is showin the zone for my master bedroom is fully open w/ 668 cfm, my livingroom damper is in position 5 (0 closed, 15 open) w/ cfm of 497, and my upstairs damper is fully closed w/ 0 cfm. I'm wondering if it's trying to blow too much air to the bedroom. It's pretty small (probably about 450 sq. ft that it's trying to cool), so maybe it needs to limit the amount of air to this zone??? This is just a shot in the dark.

    The thermostat controller is set to Media+EAC. The purifier filter is the one that came with the unit and the unit has been running since the first part of February, so a little over 4 months. Like I said though, it's new construction, so it could be dirtier than normal. It didn't look that bad when I pulled it out, but maybe it has small particles in it that I can't see that it is clogged.

    When you say shut down the purifier, do you mean to just turn the switch to the off position, or is there something else I should be doing before removing the filter? This is what I just did and the static pressure just dropped to .99-1.02. Still high, but at least it's under the 1.1 threshold.

    The LED is NOT on when the switch is on and the Air Handler is running. Any idea why that is or if this could be a big part of my problem? I put it back in and turned it on, then removed the rest of my filters and the static pressure is still at 1.08-1.11.

    The Model No. for the Air Handler is: FE4AN8006. The Model No. for the Outside Unit is: 25HNA660A300.

    The level to dehumidify is set at 50%. Do you think this is working the system too much? I live in Georgia, so I'm sure it's trying to pump alot of humidity out!

    I certainly do appreciate your thoughts and comments on this.

    Last edited by wagoss; 06-20-2009 at 08:15 AM. Reason: Forgot about LED

  6. #6
    Join Date
    Jun 2009
    Just to add to the information:

    I just got home from the lake and it was 92 in my main zone!!! The static pressure was over 1.2! I turned the system off, went to the basement, turned the breakers off, turned the air purifier off, removed the air purifier cartridge, and turned everything back on. Once the system started up in low stage the static pressure was 0.27!!! The compressor just cut off again due to a Thermal Cutout in Low Stage. It's ranging from 0.26-0.29 w/ the fan running right now.

    I don't have a clue.

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