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  1. #1
    Join Date
    Jan 2006
    Location
    Minneapolis, MN
    Posts
    70
    Here I am reading installtion instructions again. My Aprilaire 600 humidifier was installed with the "outdoor" temperature sensor placed in an inlet air duct (6" diameter, insulated, running about 12 feet to the outside wall).

    Will this work OK? Or should the sensor go all the way to the outside.

    Also, does the settings nob on the humidistat unit actually change its position with changes in humidification level? I thought I set it at 5 a few days agao and today saw it was near to 3. Or am I just going mad?

    Thanks for responses!

  2. #2
    Join Date
    Feb 2006
    Posts
    89
    lots of contoversy with "outdoor temp sensors."

    First, the location of the temp sensor, as indicated by the instructions should be located either directly outside, or if you are installing in a 90% efficient furnace, they allow you to place the sensor within 2 feet of the exterior wall in the fresh air intake. It sounds like the 6" fresh air intake that you speak of is not tied directly to the unit (possibly 80% effecient unit or not direct vented.) and is therefore not pulling enough air for proper temps.

    Here in chicago near the lake we have fluxuating humidity levels in the winter time. This sensor only reads temp. and in my experience been known to cause too much humidity causing callbacks and frustrated clients. I always install in manual mode and inform homeowners how to adjust accordingly. They work great in the more stable environments though.


  3. #3
    Join Date
    Jan 2006
    Location
    Minneapolis, MN
    Posts
    70
    Thanks for the reply. Yes, this vent is for combustion air makeup (rather than directly into the furnace).

    I am wondering if the unit is calibrating itself against a temperature difference rather than an absolute temperature measure. If this is the case, I can see how it may not make much difference if the sensor is not actually outdoors. True, thye temp in the duct is warmer than outside, but its value goes up and down with changes in the outdoor temp. So, in a relative sense, the unit should know when to increase or decrease the base humidity level, and it can be calibrated to, say, magnify this difference to accomodate the placement of the sensor in the vent. Does this make any sense?


  4. #4
    Join Date
    Feb 2006
    Posts
    89
    well it's not going to pose a real problem to your system, so if you are comfortable with leaving t there, just keep an eye on your windows. If they start to condensate a little bit, then turn the humidistat down, and if it seems a little dry in the house, turn the humidistat up.

  5. #5
    Join Date
    Dec 2005
    Location
    Cleveland, OH
    Posts
    1,965
    Or, junk the outdoor sensor, as it will no doubt fail eventually. You'd be better off with the manual mode resistor in place.

    Good? Bad? I'm the guy with the gun.

  6. #6
    Join Date
    Feb 2006
    Posts
    89
    i agree

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,755
    Eventually the seleniod will fail also, but thats not a reason for him to open and close the water valve by hand.

    Using an outdoor temp sensor for humidifiers works better then relying on the customer to adjust it every day. Let alone 2 or 3 times a day.
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