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  1. #1
    Join Date
    Apr 2011
    Location
    Chicagoland Area
    Posts
    37

    Carrier Rtu Econ Problem

    I have a Carrier 48AKD060 and u cannot get the econ working. I have verified my parameters with tech support. The main base board was replaced due to the eeprom failing. The run status shows the "Supply Fan Not On 30s-yes" and this is locking out the econ. Now tech support is telling me this is a fixed algorithm (essentially a programmed time clock) and cannot be bypassed, change, etc. Here's the kicker, my supply fan has been running for 6 hours. Anyone know if that is true. I can't belive fan proving isn't done by a DP, or current sensor.

  2. #2
    Join Date
    Jun 2009
    Location
    StL, MO
    Posts
    582
    48AK should be a VAV unit - is this correct?
    What are your SFS.M and SFS.S settings?
    UA LU 562

  3. #3
    Join Date
    Apr 2011
    Location
    Chicagoland Area
    Posts
    37
    Yes, you are correct, it is a VAV.
    My SFS.S is set at NO
    My SFS.M is set at 0

  4. #4
    Join Date
    May 2004
    Location
    SE Pennsylvania
    Posts
    923
    Have you tried to SFS.M to 2 and allow the unit to use the duct DP transducer DP as fan proof. When set to 2 the duct DP must be greater than .20 with a 3 minute delay to prove the fan.

  5. #5
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,711
    I think hvac69 may have fixed it for you Joe did tech although it sounds like you may have 3rd party controls on your unit. Your unit does have a DP switch which does have the ability to monitor fan status which may be disabling your economiser.

    I always liked to hardwired in a fan status using the VFD relay outputs.

    Quote Originally Posted by hvac69 View Post
    Have you tried to SFS.M to 2 and allow the unit to use the duct DP transducer DP as fan proof. When set to 2 the duct DP must be greater than .20 with a 3 minute delay to prove the fan.
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

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