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Discussion Starter · #1 · (Edited)
I recently purchased an Aprilaire 700 with the Model 60 control. The model 60 is designed to work with in conjunction with existing thermostats with no issue. Everything works great and I followed everything in the installation manual. The question I have is if the heat hasn’t ran in one hour the model 60 control with fan activation “on” will run the humidifier for 3 minutes to check humidity level in the home to see if more humidity is needed. When cold out many times the thermostat will call for heat while model 60 is testing levels and using furnace fan. The furnace will shut off for a second and you will hear a click nose then furnace will turn back on then heat will engage (not sure if short cycling?). Is this normal for furnace to flash off and back on? I have a video and I will attach to upload it here if allowed or provide a link. Any help would be appreciated!

Here is link to the video: https://www.dropbox.com/s/ikylz722gzssy3z/IMG_2772.MOV?dl=0

Thanks!
Jason
 

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From the way it sounds, it failed to ignite and did a reset. It succeeded on the second try although it seemed a bit longer than I'd like. That Trane board will eventually remember how long it takes to ignite and allow more time for ignition. That's assuming the ignitor is healthy. Watch during that first period to see if the ignitor is glowing. I think it does a hard shutdown if it takes more than 3 attempts. I may be wrong on how many it allows. You may need to replace it.

I can't think of any reason the humidifier would need to have any effect on the start up of heat. I realize it may interrupt the green (fan) leg of the stat on some systems to prevent backfeeding the stat and starting up the compressor but that shouldn't bother the heat mode from coming on... especially if the fan is already running. It's no different than having the fan set in manual mode at the stat.
 

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Discussion Starter · #3 ·
From the way it sounds, it failed to ignite and did a reset. It succeeded on the second try although it seemed a bit longer than I'd like. That Trane board will eventually remember how long it takes to ignite and allow more time for ignition. That's assuming the ignitor is healthy. Watch during that first period to see if the ignitor is glowing. I think it does a hard shutdown if it takes more than 3 attempts. I may be wrong on how many it allows. You may need to replace it.

I can't think of any reason the humidifier would need to have any effect on the start up of heat. I realize it may interrupt the green (fan) leg of the stat on some systems to prevent backfeeding the stat and starting up the compressor but that shouldn't bother the heat mode from coming on... especially if the fan is already running. It's no different than having the fan set in manual mode at the stat.
Thank you for the reply greatly appreciated! I had the Ecobee 3 for many years and starts up heating right away first try. If I shut off the Model 60 and tested 10 plus times through couple hours the other day and it started first call every-time. It’s only while the model 60 is enabled. Someone mentioned it does that to engage the heat process and to ensure the flue pipes are clear before starting heating process vs just engaging it for safety. Just not sure how others systems act with similar setup. Again really appreciate the support and help!
 

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Perhaps the fan being on immediately before ignition is still coasting and somehow cooling the ignitor down (sounds impossible) a little so that it causes an extended time period before it can get up to temperature. If it were me, I'd turn that feature off. It's doubling the work for the ignitor and will eventually shorten its life. An alternate method would be to install a Mars "delay on make" timer in the white leg of the thermostat. I'd say 30 seconds delay would make the problem go away. I've used these timers many times to keep users from short cycling their compressors.

Mars solid state timers

My Favorite
 

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Discussion Starter · #5 ·
Perhaps the fan being on immediately before ignition is still coasting and somehow cooling the ignitor down (sounds impossible) a little so that it causes an extended time period before it can get up to temperature. If it were me, I'd turn that feature off. It's doubling the work for the ignitor and will eventually shorten its life. An alternate method would be to install a Mars "delay on make" timer in the white leg of the thermostat. I'd say 30 seconds delay would make the problem go away. I've used these timers many times to keep users from short cycling their compressors.

Mars solid state timers

My Favorite
I have got this resolved now and transformer needed to be rewired. This resolved the furnace from clicking off the back on. Transformer needed to go to direct power vs EAC terminals on furnace board. Here is how it’s acting now when fan is engaged from humidifier and a call for heat is done by thermostat. Thanks for the replies and your help!

Have a good day!

Link : https://www.dropbox.com/s/5qahe7c7js3cefb/Video Feb 17, 9 21 12 PM.mov?dl=0
 

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That good news! Thanks for the feedback so other may be helped by your findings.

Apparently the brief cut off of power from the board EAC terminals was upsetting the Trane. Derailing it we might say. :smile: (couldn't resist)
 
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