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  1. #1
    Join Date
    Feb 2019
    Location
    PA
    Posts
    2
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    Confused Nexia Trane problem - system not switching to electric when very cold

    Hi
    I have a Trane Xv18 heat pump 5 Ton with TEM-8 Air handler, 25KW Heat pack, and Nexia XL 850 Thermostat. All installed last July, so less than a year old.

    Over the cold spell last week, I found that the electric heat would not turn on once the outside temperature fell below 5F or so... just the heat pump running, which obviously was not able to keep up with the cold. I had to turn the system to run in emergency mode in order to get the indoor electric heat to come on.

    The dealer who installed it came in and said that Nexia had a software malfunction and the problem is fixed now. I won't get in to the details but this was the last explanation he gave me starting with "these units only work down to 7 degree F and after that you need to set them to emergency heat", which I found to be a unacceptable response.

    Anyway, I poked at the thermostat, and looked at the diagnostics log... it is showing nearly 150 alerts/errors betweenJan 14 and Feb 02, a combination of

    185.13 LSPP HTG HD (Low Suction Pressure Protection in heating mode)
    184.03 LSPP CLG CO (Low suction Pressure Protection in Cooling mode - Pressure transducer out of calibration or failure)
    SOP 004.01 ODT SensFit
    185.00 CDTPH1 HD
    185.01 CDT PH1 DN

    Dealer says that's nothing to worry about... dirty air filter or nexia software fault.

    Does anyone know what the Nexia software error was and whether these errors are related to it? Should I be concerned that the system is not installed right?

    Thanks for any help.

    (it seems to be function OK as long as the outdoor temp is over 10F.. the weather here in PA has been warmer since the cold spell last week so I can't tell if it will again stop functioning when the temp falls below 10F)

  2. #2
    Join Date
    Aug 2007
    Location
    Rochester, NY
    Posts
    247
    Post Likes
    Nexia did a software update that caused many problems for a day. The low suction errors are usually simply alerts during normal operation especially in very low ambient temps. Nothing to worry about as long as it seems to be heating with the heat pump normally. Your contractor is misinformed, leave the system in heat and let the stat calculate when to stage the electric heat.


    Sent from my iPad using Tapatalk

  3. #3
    Join Date
    Feb 2019
    Location
    PA
    Posts
    2
    Post Likes
    Thread Starter
    Thanks, ebierly

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