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  1. #1

    Carrier ERV running on HIGH all the time - Infinity Control and FE4 AHUs

    Hi guys,

    I have a fully Carrier system, installed by a well-respected company in Nashville TN. It's a geo system - FE4ANF005 handler, 50YDS038 heat pump and an infinity control. There are two of these systems, one for each floor - the house is 2500 sf per floor.

    We have an ICF home and it's pretty tight, so the installer recommended a Carrier ERV (ERVCCLHA1200A) for air exchange. This jived with what I'd researched before building (tight homes can benefit from mechanical ventilation) so we installed one per his suggestion, and it's hooked to the downstairs unit, ducted properly (from what I've researched).

    The problem is that the ERV is ALWAYS running on HIGH, even though the Infinity control is set to AUTO for Ventilator. There are several ERV settings on the control (AUTO, LOW and HIGH), but when I query the Infinity control to see what components are installed and what mode they are currently running, the heat pump and fan reports vary depending on the time of year (some times Cooling / Low Stage or Heating / Low Stage or Cooling / High Stage etc) but Ventilator ALWAYS reports HIGH. And when I go and visit the ERV in the mechanical room, it is always running unless I unplug it.

    I read on this forum about a user who was complaining about an overly dry house in the winter, one that was spray-foamed and pretty tight. Turned out he had an HRV running and the forum brains (you guys) suggested that it was running too much and introducing too much outside (dry) air in the winter.

    Our house is also pretty dry, and I'm wondering if the ERV needs to be addressed, because I can't imagine the system would be calling for that much air exchange.

    1- Does this sound like normal operation for this equipment?
    2- Is there a way to diagnose if it is communicating correctly?

    Any thoughts would be appreciated!

    Thanks,

    Sandy

  2. #2
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,467
    Quote Originally Posted by tippsand View Post
    Hi guys,

    Our house is also pretty dry, and I'm wondering if the ERV needs to be addressed, because I can't imagine the system would be calling for that much air exchange.

    1- Does this sound like normal operation for this equipment?
    2- Is there a way to diagnose if it is communicating correctly?

    Any thoughts would be appreciated!

    Thanks,

    Sandy
    You need a fresh air change in 4-5 hours when the home is occupied. During cold windy weather, you may get enough natural infiltration. During calm warm weather, you get near zero infiltration. Your fresh air ventilation system should make an attempt to provide the correct amount of fresh air when needed.
    Sounds simple.
    Some get a plenty big system and operate it 24/7. Heat and humidify to air to your desired comfort levels. They call it a day.
    Others operate the ventilation system when the home occupied with a occupancy timer.
    The most ideal method would be to monitor the CO2 levels and operate the fresh ventilation when the CO2 levels rise to a specific level indicating occupancy and a lack of natural fresh air change.
    You can buy a CO2 meter to $250. Measure the moisture level outside the home, estimate the moisture added by the occupants, and measuring the inside moisture levels also indicates the amount of air infiltrating (ventilating) the home.
    An example is 4 occupants adding 2 lbs. of moisture per hour raises the dew point of 150 cfm of 25^F. When the outdoor dew point is 8^F which is 25^F, 50%RH. If the home is 68^F, 30%RH, 35^F dew point, with 4 occupants adding 2 lbs. of moisture per hour, you getting about 150 cfm of fresh air.
    A good a/c company has access to someone who should be able to figure this out.
    A little complicated. Tell us how many occupants and the actual indoor temp/%RH of your home. We can estimate the amount of fresh air ventilation you are getting.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  3. #3
    I'm not at the house right now.

    We're two adults, one working from home full time. Two kids (one 6, one 18mos). Indoor winter temp 72, RH typically 35% but it feels dry. Outdoor temp in Nashville varies from 20F to 50F at this time of year.

    I found a few other threads in my research on this board about this same issue - seems a lot of people feel that the Infinity control doesn't really give great control over any ERV / HRV other than running on HIGH all the time if the Infinity control is set to AUTO - one guy from MN switched to a dedicated ventilator control and is happier.

    I'm just concerned that it's over-ventilating, that's all.

    Let me know

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