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  1. #1
    Installed a 700 to a Lennox pulse furnace. It worked two weeks and is now dead. During it's working time, the unit would engage at the same time as the furnace fan wether the furnace was burning or not. Basically a lot of on off's. The light indicators on the control are both out. No activity at test mode with furnace running. I like to keep things simple. If a suggestion to replace the Auto trac humidity control: Would a 4016 low tech work or another Auto trac. Is there anyway to test which component is not working?

    Thanks in advance

  2. #2
    Join Date
    Jul 2001
    Where did you pick up power?

  3. #3

    aprilair 700

    On the 24 volt power relay on the furnace.

  4. #4
    Join Date
    Mar 2003
    Media, Pa


    The 700 series takes 110vac and has its own transformer for humidistat. You probably smoked trans on unit

  5. #5
    Join Date
    Feb 2004
    chicago suburbs
    jps is right bucking transformers.

  6. #6
    Join Date
    Jan 2006

    Q for JPS or tinner73

    My HVAC guy has my 700 installed except for the final wiring of the humidistat as neither if us could figure out the supplied instructions and he has never intalled the 700 before. He wired the 120v for the power cord off the HUM terminal so it is switched with the heat cycle. He thought we should be able to use the 700's internal transformer to power the humidistat but asked me check with Aprilaire as we couldn't get them on the phone when he was doing the install. Aprilaire tech support emailed me back and said"

    "...The Model 700 does have a transformer inside
    of it to power the solenoid valve. This transformer can not be used to power the humidistat. The humidistat does need to be powered from a separate 24 VAC source. We can't power the control from the humidifier and then ask the control to switch the power to turn the humidifier on and off...."

    But then JPS said the humidistat should be powered from the internal transformer. My other option is to have him wire a transformer off the HUM terminal to power the humidistat but tinner73 says this is bad too.

    So what is the correct way to wire one of these?

    Thanks for any help.

    kind regards,


  7. #7
    Join Date
    Oct 2004

    up in smoke

    up in smoke all i can say....

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