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  1. #1
    Join Date
    Jun 2008
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    37

    Carrier Infinity- Fan Makes Too Much Noise on High Speed-Can it be adjusted?

    Greetings,
    I've have a Carrier Infinity Tstat Controller. When the unit comes on, it always comes on at the HIGH fan speed. The noise is driving me crazy. It is not the noise from the air movement, but it is the sort of whirling noise from the spinning of the fan. Is there any way to limit the fan's speed so that it only using the MED fan speed whenit comes on?

    Also, if I manually set the fan speed to MED so there is constant flow of air around the house, after the unit kicks in to heat the house and after it is has reached its programmed temperature, it resets to AUTO, not back to MED. I figure if I put the unit on HOLD, it will stay at MED fan speed, but then I lose the set-back programming at night when I go to bed.
    Is there a way to make it reset to MED after it has cycled???

    The main problem is the noise:
    At the HIGH fan speed, the CFM = 1957; the RPMs= 1111; the Static Pressure = .70.
    At the MED fan speed, the CFM = 1307; the RPMs= 766; the Static Pressure = .35.
    Does this shed any light on the noise problem???
    Thanks... Gary

  2. #2
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    Quote Originally Posted by goddi View Post
    Greetings,
    I've have a Carrier Infinity Tstat Controller. When the unit comes on, it always comes on at the HIGH fan speed. The noise is driving me crazy. It is not the noise from the air movement, but it is the sort of whirling noise from the spinning of the fan. Is there any way to limit the fan's speed so that it only using the MED fan speed whenit comes on?

    Also, if I manually set the fan speed to MED so there is constant flow of air around the house, after the unit kicks in to heat the house and after it is has reached its programmed temperature, it resets to AUTO, not back to MED. I figure if I put the unit on HOLD, it will stay at MED fan speed, but then I lose the set-back programming at night when I go to bed.
    Is there a way to make it reset to MED after it has cycled???

    The main problem is the noise:
    At the HIGH fan speed, the CFM = 1957; the RPMs= 1111; the Static Pressure = .70.
    At the MED fan speed, the CFM = 1307; the RPMs= 766; the Static Pressure = .35.
    Does this shed any light on the noise problem???
    Thanks... Gary
    High static. What size is the unit?

  3. #3
    Join Date
    Jul 2000
    Location
    Northern Wisconsin
    Posts
    2,013
    What kind of heating system do you have. Obviously it's Carrier and it's an Infinity system, but do you have a gas furnace, heat pump, dual fuel? The controller is just basically a switch with brains that can talk to other parts of the system.

    Does it do this all of the time night and day or when coming out of a programmed setback?

    The controller, depending on it's version and how it's been setup in advanced mode, can set the fan speed according to the time of day just like it can temperatures. You manually setting it to MED could be being overridden by this kind of setting.

    You say the unit ALWAYS runs at high fan speed? Does it also indicate that it's in high fire (for a furnace) or high speed (for a heat pump)? Does it ever use the lower heat functions/capacities? Coming out of setback with a large temperature difference to make up the controller may be going right to high capacity mode to heat the home. This can be the case sometimes if the controller is set to not use intelligent recovery, but instead a time has been programmed in as when the unit should come out of setback.

    As far as the motor itself making an annoying noise, you're moving 1957 CFM's worth of air at fairly high static in high fan mode. The motor may be contributing to the noise you're hearing, but I'd suspect that much air moving at that kind of static is drowning out any small amount of noise those motors make. That is unless you are standing right by the unit itself. 20 some years of working with the ECM motors that are in the Carrier equipment, I've yet to ever see one that made a noise you could hear over the air flow noises. But of course there is always the first time.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  4. #4
    Join Date
    Jun 2008
    Posts
    37
    Responses below in Bold:

    Quote Originally Posted by firecontrol View Post
    What kind of heating system do you have. Obviously it's Carrier and it's an Infinity system, but do you have a gas furnace, heat pump, dual fuel? The controller is just basically a switch with brains that can talk to other parts of the system.
    Greetings,
    Here are some of the details:
    It is a Carrier Hybrid unit. I have a gas furnace and a heat pump. The unit is a Carrier Infinity 16 Heat Pump, 5 Ton, Infinity 80 Gas Furnance. I've had the theromstat changed 3 times because the reading from the Left Button that shows the filter usage give wild readings. After a few weeks, it can jump from 0% to 100%, then to 20%, to 50%, then to 10%...etc. The Carrier tech guys says it is just the way it works. The readings are taken from the RPMs so it will fluctuate. I can't understand why they think that is OK... anyway, back to my other question.


    Does it do this all of the time night and day or when coming out of a programmed setback?
    "By this", do you mean the noise or resetting to AUTO? I think I misspoke. The HIGH speed fan noise is most noticable in the early mornings and at late night when it seems like it is ramping up to raise the temperature. I was just watching the T-stat and it was running at manually-set MED (CFMs=1564;RPMs=923; S.P.=.51) and then dropped down to AUTO (CFMs=958;RPMs=588; S.P.=.22). Both were acceptably quiet. But, after it reaches the set temp and turns off, it will revert from my previously set MED fan speed to the AUTO fan speed.


    The controller, depending on it's version and how it's been setup in advanced mode, can set the fan speed according to the time of day just like it can temperatures. You manually setting it to MED could be being overridden by this kind of setting.
    I have looked through the Advanced Mode but I can not see anywhere where you can change/adjust the fan speed. The T-stat was replaced 1 year ago with the latest Infinity T-Stat.

    You say the unit ALWAYS runs at high fan speed? Does it also indicate that it's in high fire (for a furnace) or high speed (for a heat pump)? Does it ever use the lower heat functions/capacities? Coming out of setback with a large temperature difference to make up the controller may be going right to high capacity mode to heat the home. This can be the case sometimes if the controller is set to not use intelligent recovery, but instead a time has been programmed in as when the unit should come out of setback.
    The HIGH fan speed is most noticeable late at night and early mornings. No, the furnace or heat pump does show LOW fire; rarely on the HIGN setting. The setback is to 67 at night; and set to come on at 69 in the mornings.


    As far as the motor itself making an annoying noise, you're moving 1957 CFM's worth of air at fairly high static in high fan mode. The motor may be contributing to the noise you're hearing, but I'd suspect that much air moving at that kind of static is drowning out any small amount of noise those motors make. That is unless you are standing right by the unit itself. 20 some years of working with the ECM motors that are in the Carrier equipment, I've yet to ever see one that made a noise you could hear over the air flow noises. But of course there is always the first time.

    Yes, I understand the S.P. is on the high side. That is why I want to somehow make the fan to not go to the HIGN fan speed setting. It is very annoying at night when trying to sleep and in the morning when still in bed. Closing the bedroom doors helps a bit but not much. It is not the air movement noise...more like a humming noise. I took off one of the intake grilles but it did not make a difference. This has been going on for 5 years now and I can't take it any more. I need a fix!
    Gary

  5. #5
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
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    5,060
    Quote Originally Posted by goddi View Post
    Responses below in Bold:
    Repair the duct work to allow the cfm required for the system to function.

    The variable speed motor is increasing to deliver the required CFM

  6. #6
    Join Date
    Jun 2008
    Posts
    37
    Quote Originally Posted by second opinion View Post
    Repair the duct work to allow the cfm required for the system to function.

    The variable speed motor is increasing to deliver the required CFM
    ===============================
    Greetings,
    The duct work can not be re-designed. It is a finished home. So I am trying to attack it from the other end by not allowing it to go to the HIGH fan setting. If it were only allowed to get to the MED fan speed, is there any problem with that? Can it be done?
    Gary

  7. #7
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    High speed is based on the highest cfm requirement in either heating or cooling. Is airflow set to comfort alreasdy. Try that first. After that you can try the minimum setting.

    Another option is to use better quality commercial grade registers that flow more air. Thus can make a suprisingly big difference. The cheap $5 stamped steel grills are junk. Poor throw and low cfm capacity.

    Afterr that your stuck without reducing equipment size or ductwork.



    Sent from my SGPT12 using Tapatalk 2

  8. #8
    Join Date
    Jul 2000
    Location
    Northern Wisconsin
    Posts
    2,013
    I don't see anywhere mentioned anything about a zoning system so I will assume your system doesn't have one. Also not mentioned is if you open or close registers as a daily or time of day thing. I'm mentioning both of these because if either were true it would make a difference.

    First of all the system that you have makes all of it's decisions on whether to run either the furnace or HP at either low of high. The system also decides exactly what speed (RPM) to run the blower motor at and makes this decision from a test that it runs once a day (mine doing that at 1pm each and every day). The test is designed to "measure" the static pressure at that instant in time and the blower speeds for each stage of heating or cooling are determined from that information for the next 24 hours. This automatic function is not something that you can change nor can you change whether the unit goes to high on either the furnace or HP through the control.

    Erratic filter use indications could be an indicator that something either in the duct work or registers is causing fluctuations in the static pressure of the duct work. So many different things could cause this. From the simplest thing like the air filter is moving around to a balancing damper is moving to the system has insulated flex duct and the static pressure is fluctuating due to the flex changing it's air flow characteristics.

    From your descriptions the noise/humming is most noticeable when the house is quiet, late at night and early mornings. I won't assume anything here, but that can be sometimes attributed to not a louder noise, but a more noticeable noise due to everything else being still.

    The humming noise: This can sometimes be caused by a return register itself. The metal openings (strips of metal) can actually start to vibrate from the air moving through them and build up a rather annoying resonance sound that can get rather loud. I've chased a few of these down and sometimes it takes removing them one at a time and waiting a day or so to see if the noise goes away. If it does you've found the source and then it's just a matter of figuring out what needs to be changed or done to stop the noise. Return registers especially can make this kind of noise if the air flowing through them exceeds the designed amount and sometimes it can be caused by lint or dust collecting on them. I've seen the noise go away on them when they seem perfectly clean, but after removing them and cleaning them thoroughly the hum went away. Basically the small metal strips can act like tuning forks.

    You've said that the duct work is buried and can't be modified, with that said the only thing you have left is registers. First make sure all supply registers are fully open all the time. Secondly make sure that all return air registers are clean as new and not blocked by furniture or anything that can restrict the air flow through them. Placing furniture an inch away from a return air register is not unblock by the way. Try removing all of the registers in the house if this is possible and see how the system reacts to it. There are options as to styles and makes of registers and you might be able to find replacements that will do a better at allowing air flow on both supply and return sides.

    The furnace and control will continue to do what they are doing and there is nothing you can really do to change that, the factory programs things to protect the equipment with proper air flow and to help assure maximum efficiency. Sometimes these "smarts" run head long into an installation where the air supply and return systems aren't 100% compatible.

    The only adjustment available was mentioned earlier by someone..... and that is you have minor "tweaks" that can be set by choosing the available air flows in the advanced setup features.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  9. #9
    Join Date
    Jun 2008
    Posts
    37
    Greetings All,
    No, I have no zones; registers don't close.
    The duct work is not buried... it is rigid metal ducts throughout the house.
    I have removed both return grilles (first floor and second floor) but it did not make a difference as far as the noise goes. The only thing that reduces the 'hum' or 'whirling' noise is to reduce the fans speed manually to MED. But I can not control the fan speed when the T-stat is controlling everything.
    It seems that too much air is being pushed the duct system. If I could only have the fan not go to HIGH speed, I could live with it. But you state that there is no way to do this.
    I will try your tweaks in the future but I don't think there is anything that would help. All registers are opened. Maybe I will try a cheaper 1" filter instead of my 4 " filter.
    Thanks... Gary

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,125
    Is the return to your furnace on one or both sides? or does it come in the bottom of the furnace.
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    How many times must one fix something before it is fixed?

  11. #11
    Join Date
    Jun 2008
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    37
    Quote Originally Posted by beenthere View Post
    Is the return to your furnace on one or both sides? or does it come in the bottom of the furnace.
    ======================
    Both returns join together just above the furnace and it comes in at the bottom side of the furnace.
    Gary

  12. #12
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    A better quality supply register can flow 2x the air with the same pressure drop and noise.

    I didnt see mentioned if the blower was set to m"comfort". It can also be set to "minimum".



    Sent from my SGPT12 using Tapatalk 2

  13. #13
    Join Date
    Jun 2008
    Posts
    37
    Yes, sorry, I forgot to mention it. Yes, the 'comfort' setting is selected. Is this a good thing to have them selected?.....
    Gary

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