I have an Aprilaire humidifier model 700 with the #56 humidistat with outdoor sensor. It was installed 7 years ago and has been running fine until now. I change the pad yearly. This season I noticed that the humidifier does not seem to be running. I keep the dial on the humidistat at 5. I turned it up to the test mode which is past 7 and it runs. But when I turn it back down to lower than 7 it stops. I can feel it is dry in the house so I know that there is not enough humidity and thus the humidifier should be running. There are 6 wires to the humidistat (but I did not touch any wiring). Nothing was altered, just a new pad replaced, but it was not running this season before pad replacement - but was running last season. I'm in the Chicago area.
Thanks for any help!!!! James
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Is this a newly installed unit it sounds as if there's a wiring issue. Could you show a picture of the wiring terminals. If this is not a new install try turning of your furnace fan.
Depending on the age of your furnace you may have an aux terminal for a humidifier. If not, you should use the white wire (heat) coming from the homes thermostat to power up the humidistat and ultimately bring on the humidifier. This way it will only run when in heating mode.
Based on the information that I have found changing the humidifier from a manual setting to an automatic setting is somewhat easy. It will require you to remove the little blue resistor that is located at the humidistat on the two screws labeled odt and replace that with an outdoor temperature sensor part 8052 that needs to be ran to the outside of the home. Depending on your technical abilities you may be able to perform this procedure, but may need to get a contactor involved.
you need to make sure your humidity level in the house isnt higher then what your humidifier will provide at any givin outdoor temp. this chart is in the owners manual. you cant remove the wires going to the ODS or it will give an error unless you have a resistor to put in its place. Anyway if the humidifier works in test mode according to AA it works so you may have higher humidity than you think, the highest your gonna get is 45% as the temp outside drops it will allow less humidity so it doesnt cause window condinsation (property damage) here is a copy of the chart. the #s on the left are the dial setting
TABLE 2 – % Relative Humidity Guide
Outdoor Temperature (°F)
-10°F 0°F 10°F 20°F 30°F 40°F
1 10% 10% 10% 15% 20% 25%
2 10% 10% 15% 20% 25% 30%
3 10% 15% 20% 25% 30% 35%
4 15% 20% 25% 30% 35% 40%
5 20% 25% 30% 35% 40% 45%
6 25% 30% 35% 40% 45% 45%
7 30% 35% 40% 45% 45% 45%
white wire on fan motor ( neutral ) is placed under clamp on relay , one yellow wire on relay goes to one wire on the solenoid valve , other yellow wire goes to the humidistat
×