Model 800 has 3 sets of capacity, which one is right for me?

Saturday, February 11, 2012 by Aprilaire Team
Consumer question:

My house is 6000sq ft. What capacity should my Aprilaire model 800 humidifier unit be set to, 11.5,20.5,or 23.3 gallons per day? Also how do I know what its set at now? I cant seem to get it about 37% humidity. I have a digital new thermostat.

Aprilaires' response:

Thank you for your email regarding your model 800 Aprilaire steam humidifier. Your model 800 can work with a 110, 208 or 240 volt power supply. The higher the voltage, the higher the gallons per day output. A power supply of 240 will produce 23.3 gallons per day. A home of 6000 sq. ft with 8" ceilings would typical need 23- 25 gallons per day. Your HVAC installer would know how they sized your home for humidification and what power supply they used. As long as your thermostat has dry contacts, it may be used to control humidification from your model 800. We ask for you to please contact them to discuss how they have wired your system.


My humidifier is very chatty well really just chatering.

Thursday, February 9, 2012 by Aprilaire Team
Consumer question:

My 700M makes a chatering noise when the humidity control is moved and when the humidity changes. I think it is coming from the water selenoid, but I can not be sure.

Aprilaires' response:

Thank you for contacting us. The problem that you are experiencing has occurred with other customers that were having issues in getting the proper power to the humidifier to allow the humidifier turn on. Basically what is happening is that the solenoid is not getting the full 24 volts and 10 volt amps required to open properly. Depending on which generation of 700 humidifier you have and what is wired to the humidifier between the humidistat and humidifier would determine what the correct trouble shooting step that I would suggest at this point. If you could advise the color of the unit and what is wired between the humidistat and humidifier, I would then be able to give you a better direction in trouble shooting the humidifier. This may be easier if you called us with your response at 800-334-6011. You may still need to have an installing contractor to trouble shoot the humidifier further. I look forward to your response. If you have any other questions please contact us at 800-334-6011.

My solenoid is open with no voltage, what's up with that?

Tuesday, January 24, 2012 by Aprilaire Team

Consumer question:

I have a 560 humidifier with a model 883321B controller. The past 6 years we owned the house we never used the humidifier but now we are trying to use it. We recently had a evaporator coil and new thermostat installed and the installer ran new wiring for it. When I tried to run the humidifier, water continually runs weather the furnace is on or off and no matter what the humidistat is set to. There was no voltage at the solenoid valve when I checked.

Aprilaires' response:

Thank you for contacting us regarding your model 560 humidifier. When the unit is wired properly, the solenoid valve should only open when the furnace and HVAC blower is running. If there is no voltage at the solenoid and it is open, then the valve may be stuck open due to a build up of particles or sediment.

In order to send you to correct wiring diagram, we would need to know if you have a manual or automatic humidistat. Additionally, to better understand why your unit is not operating properly, you have the option to call our technical support department at 1-800-334-6011 to troubleshoot the unit with one of our technicians over the phone. The technician may be able to diagnose what the problem is and point you in the right direction regarding service or installation manuals.

Our tech support department is available Monday through Friday, 7 am to 5 pm CST.

Where is the humidity sensor on my humidifier?

Thursday, December 29, 2011 by Aprilaire Team
Consumer question:

We have a manual control for our Aprilaire Humidifier that is located in the same room as the furnace. Where is the sensor that detects humidity? Is it in the control? Is it on the thermostat on our main level? Where are the sensors normally installed? Also, what % of humidity should our house be at to still be safe without having too much humidity? Also - our Aprilaire runs without our furnace on - our fireplace heats our house well enough to not have the furnace run - it is ok to have the Aprilaire run thru the ducts with just cold air?


Aprilaires' response:

The humidity sensor is located in the humidistat controller. Now, which controller you have will determine the location of the sensor in the humidistat.

Do you have a 'test / reset' position on the controller? If you do, then the sensor is sticking out of the back of the controller and is located in the ductwork.

If you do not have a 'test / reset' position, and printed directly on the front of the controller are the number 15% through 45% then the sensor is inside the humidistat. If you have this mounted on the wall, it is sensing the air in the room it is located in. If this is installed into the ductwork, then it would be sensing the air in the duct.

It is acceptable to run the humidifier on just a fan call, no heat call. Just make sure to have hot water into the humidifier.

Any level of humidity is ok to have as long as you do not have condensation on your windows.

Power, power am I getting power?

Wednesday, December 28, 2011 by Aprilaire Team
Consumer question:

We are quite happy with our unit, but we have a question. When the cover is lifted off to change the filter, the plug is disconnected so the fan, of course is not moving.
But,how can we make sure the unit is getting power? We have never seen the fan blades turn even when we plug the unit in while the cover is off. Shouldn't we be able to hear the fan turning or feel air coming out of the top of the humidifier? (It's a model 760.)

I just plugged a fan into the out-let and the fan will not run. The outlet may not be wired correctly. But, please tell us if we should be able to feel air coming out of the unit or hear the fan moter?


Aprilaires' response:


Thank you for contacting us regarding your model 760 humidifier. The model 760 has its own 24 volt transformer built into the unit therefore it has all of its own power. If you would like to see if the fan is working while the cover is on, simply touch the brown leads together while the unit is plugged into a powered outlet. This would complete the 24 volt connection to the relay, turning the fan on and opening the solenoid. This is a low voltage connection so there is no risk of injury. You can perform this test while the furnace is off, this way the sound of the furnace running will not interfere while you are listening for the fan on the 760.

If the fan and solenoid operate the unit is ok. If not, we recommend contacting your installing contractor to come to your home and troubleshoot the unit. However, you have the option to contact our tech support department at 1-800-334-6011 and troubleshoot with one of our technicians. Our tech support department is open Monday through Friday, 7 am to 5 pm CST.

Can I just occasionaly run my furnace blower to add humidity without having the heat on?

Wednesday, December 14, 2011 by Aprilaire Team
Consumer questions:

Can I just occasionaly run my furnace blower to add humidity without having the heat on?



Aprilaires' response:

Thank you for contacting Aprilaire.

Yes, it is possible to create humidity on just a fan call. In order to accomplish this, you will need to have the controller wired to know when the fan is on, and have hot water run to the humidifier.

If the humidistat controller is currently wired to obey a call for heat, then having the fan on will not change anything for humidity.

Please let us know if you have any further questions.

Dip, Dip, Dip Switch settings...

Tuesday, December 13, 2011 by Aprilaire Team
Consumer question:

Your website says "The unit automatically turns on the dehumidifier blower for 2 minutes in a preset timeframe to sample temperature and dew point. You can customize the interval to 30 min, 1, 2, or 3 hours." How can I change the "preset timeframe"? The manual says nothing about how or where to modify this setting.


Aprilaires' response:

Thank you for your email regarding your model 1710A Aprilaire humidifier. There are a set of dipswitches on the control board labeled cycle period. The control board is located behind the control kob. You make access it by removing the access panel. The cycle period can be adjusted for 30 minutes, 1 hour, 2 hour or 3 hours. The sampling of the air to determine how humid the air is will occur with 3 minutes left in whatever option (30 minutes, 1 hour, 2 hour or 3 hours) you have selected. The default is one hour.

I would like to get an Aprilaire 1750A and run it separately from HVAC.

Friday, December 9, 2011 by Aprilaire Team
Consumer question:

I would like to get an Aprilaire 1750A and run it separately from HVAC. I want the dehumidistat to have a digital readout with the usual on/off and push button up/down of humidity setting. Which dehumidistat? Model #70? Model #75? What's the difference? Another model?

Aprilaires' response:

Thank you for contacting us with regards to our model 1750A Dehumidifier. Models 70 and 75 will each work with this model. The difference lies in how the controls sense humidity and how they use that information to create a set point. The model 70 sends humidity, temperature and set point values to the dehumidifier for it to use in determining if humidity is too high. The 75 works with a simple 2-wire signal to turn the dehumidifier on and off. This is a simpler control and works the way most other manufacturers' de-humidistats will work.

Please let us know if we can be of further assistance.

Humidity please for my 2 story house.

Friday, December 9, 2011 by Aprilaire Team
Consumer question:

We have a 2 story home with the humidifier installed on the forced air furnace in the basement. The controls are mounted on the side of the furnace return air ducting in the basement. I assume the control senses the humidity of the basement since that is where the control is mounted and I can not see any remote sensor input. The humdity of the basement is different than the humidity in the bedrooms on the second floor. How does the system sense the humidty upstairs where humdity is needed most in the winter? The basement stays fairly humid all year around. We have the unit set at 7 but still wake up dry and scratchy in the mornings as I believe the unit is controlling to the basement humidity and not to the second floor humidity. Should the control unit be mounted on the 2nd floor so it can sense the second floor humidity level and control to that? If so, can the unit handle the longer control wiring or is there a remote sensor option that can mount on the second floor and still have the control unit in the basement?
Thanks in advance for any help.


Aprilaires' response:

Thank you for contacting us with regards to your model 600 Humidifier. The humidistat for this unit should be locate on your duct work near the furnace. The sensor is actually located inside the duct work on the back of the humidistat. There should be an opening cut into your duct work to accommodate the sensor. The air that's passing through your duct work will come from all over your house, but unless there are returns in your basement, that air should not affect the sensor.
We do not make remote sensors for our humidistat. Wherever the stat is located, that's where the air is sensed. With our manual controls that means the air surrounding it. With our automatic controls, it senses the air inside your duct work. Based on the information you provided, your control does not need to be moved.
Please let us know if we can be of further assistance.

What is this red LED light on my Aprilaire 600 humidifier?

Wednesday, December 7, 2011 by Aprilaire Team
Consumer question:

Solenoid valve does not appear to open. Shut down furnace. Changed water panel. Adjusted furnace to call for heat. With blower on, about 1 minute, green "change water panel" light and red LED inside the control panel, both come on simultaneously. After about 1 second green light goes off. Red LED, marked D10, on the circuit board remains on. Moved control knob toreset/test position for one minute, and adjusted to previous "normal" humidification setting. Red LED stays on, and no water is being fed into evaporator. -Water to solenoid is "on." Any suggestions??

Aprilaires' response:

Thank you for your email regarding your model 600 Aprilaire humidifier. The red LED indicates the outdoor temperature terminals(ODT) are not receiving a temperature reading from the outdoor temperature sensor. The humidifier control will not function without the outdoor temperature reading. Our recommendation is to have your HVAC installer review the wiring and test the outdoor sensor and replace sensor if necessary.

Will the Aprilaire model 400 provide enough humidity for my 2400 sq ft house?

Thursday, December 1, 2011 by Aprilaire Team
Consumer question:

Will the Aprilaire model 400 unit adequately humidify my 2400 sq ft home?


Aprilaires' response:

Thank you for your email regarding our model 400 Aprilaire humidifier. There are may variables which affect the size home our humidifiers can effectively humidify. The tightness of the home and run time of the heating system will typically determine which model to select. The model 400 is a drain less model which can only add humidity when the heating system is operating. If the heating system has a short run time then the humidifier will as well. The model we typically suggest for heating systems with short run times is the model 600 as it can be wired to run on a fan call provided the humidifier is supplied with hot water. Our recommendation would be to discuss your options with your HVAC installer.

Thank you for giving us the opportunity to be of service.

Does my one touch control work?

Thursday, November 24, 2011 by Aprilaire Team
Consumer question:

The control for the air cleaner is saying it is filtering even when it is disconnected from the unit and also when the unit is not actually filtering.

Aprilaires' response:

Thank you for contacting us with regards to your model 5000 Electronic Air Cleaner. The air cleaner control works on a negative signal logic, meaning that when it sees no connection to the furnace or thermostat, it assumes the fan is running and the air cleaner is working. The control needs to be wired in properly in order to truly see when the fan is active or not. If it still shows Filtering when the control is connected, there may be a problem with the wiring. We would recommend that you contact your installer to troubleshoot the installation further.

We appreciate the opportunity to be of assistance.

Couple of questions on the model 600 Aprilaire humidifier...

Saturday, November 19, 2011 by Aprilaire Team
Consumer question:

I purchased the 600(digital) and have 2 questions... 1. Does the manual mode resistor come with this unit in case I cant install the temp sensor outside and 2. Will extending the temp sensor wires with like gauge wiring cause any issues? I have a 20 foot run to get outside and the temp sensor wires are a foot long! Thank you and any tips would be appreciated.

Aprilaires' response:

Thank you for your email regarding your interest in our model 600 Aprilaire humidifier. The model 600 humidifier control includes a humidistat which has an on board manual mode resistor. If you decide to use the outdoor sensor you will need to move the manual/auto switch on the humidifier control from manual to auto. This allows the control to use the outdoor sensor instead of the onboard manual resistor. You can extend the outdoor sensor using thermostat wire which is typically 18 gauge. The maximum length you can extend it is 300 feet.

If we have a UV germicidal lamp installed in the same section of the heating duct of our system as the currently installed humidifier(which is above the N-coil), will the UV light harm the aprilaire humidifier, internal wiring, or pads.

Friday, November 18, 2011 by Aprilaire Team
Consumer question:

If we have a UV germicidal lamp installed in the same section of the heating duct of our system as the currently installed humidifier(which is above the N-coil), will the UV light harm the aprilaire humidifier, internal wiring, or pads.


Aprilaires' response:

Thank you for contacting us regarding the effects of the UV light. Because UV naturally breaks down plastics, we don't recommend direct exposure on the plastics. However, because we understand that in some applications direct exposure is unavoidable, we upgraded the plastics that are used in our humidifier units. The older plastics that were used for the internal components were white in color. These plastics have been upgraded with black plastic that is more resistant to the UV lights. While the black plastic is more resistant to the UV light, it will still break down over time with direct exposure, but it will last longer than the white plastic.

If your 700 still has white plastic components inside that are exposed to the UV light, you can contact your contractor about getting the upgraded plastic components. You also have the option of ordering them from the our estore. Follow the link below for more information:

http://estore.aprilaire.com/catalog/humidifiers/model-700-series-parts

If your plastic components are already black, then there is nothing more you would need to do.

If you have any further questions regarding this or any of our products, please feel free to contact our customer service department at your earliest convenience.

Aprilaire model 500 install perfectly but what about this outdoor temp sensor? Is it needed?

Friday, November 11, 2011 by Aprilaire Team
Consumer question:

I installed the 500A on our furnace this weekend without any trouble. We cannot get access for the outdoor temp sensor, due to the 100 year old brick walls, so we are running the Model 60 Controller in manual. Because there was no return duct available the Model 60 has been mounted on an interior hallway wall. As per the instructions, the foam gasket was removed. The Model 60 hygrometer seems to be reading 10% high. We happen to have two digital hygrometers here and they both read about 36% while the Model 60 is showing 45% causing humidifier not it turn on. Can the model 60 be calibrated or can I get a replacement?


Aprilaires' response:

Thank you for your email regarding your model 500A Aprilaire humidifier. The model 60 is not designed to be installed in the living space. This is because the humidity sensor on the back of the control needs airflow past it to receive an accurate reading of the humidity. When mounted to a wall the airflow is blocked. The model 60 can not be calibrated. It has an accuracy of +/- 3%. As a result if it is measuring 45%, the humidity is between 42% - 48%.

Your email indicated there was no cold air return duct, however the return is necessary to install the humidifier. Our recommendation would be to re-locate the model 60 up stream of the humidifier on the cold air return. If this is not possible you will need to obtain our manul humidistat model 4655. The 4655 can be mounted in the living space. We ask for you to please contact the place of purchase to purchase the 4655.

Thank you for giving us the opportunity to be of service.

Is the Aprilaire model 8466 thermostat Dual Fuel capatable, if so how do you set it up ?

Friday, November 11, 2011 by Aprilaire Team
Consumer question:

Is the 8466 Dual Fuel capatable, if so how do you set it up ?


Aprilaires' response:

Thank you for contacting us with regards to your model 8466 Thermostats. There are two requirements for dual fuel mode. The thermostat must be in heat pump mode (set by the switch on the back), and the auxiliary heat must be set to Gas or Oil. Under these conditions, whenever the thermostat stages from compressor to auxiliary, the thermostat will lock out the compressor.

This thermostat can also act as a fossil fuel kit. When the outdoor temperature sensor is installed and enabled, the thermostat enables settings for high and low balance points. The high balance point will lock out the auxiliary heat when the outdoor temperature rises above that level. The low balance point locks out the compressor when the outdoor temperature falls below that level. In-between, the thermostat will stage based on demand. Please see your installation instructions for more information.

We appreciate the opportunity to be of assistance.

Considering purchasing a 600. It humidifies to a max of 45%, but only at certain temps. Why only 45% at no colder than 10degrees, when the chart on your site shows 50% as the optimal for health?

Monday, November 7, 2011 by Aprilaire Team
Consumer question:

Considering purchasing a 600. It humidifies to a max of 45%, but only at certain temps. Why only 45% at no colder than 10degrees, when the chart on your site shows 50% as the optimal for health?


Aprilaires' response:

Thank you for contacting us with regards to our Aprilaire Humidifiers. As humans, we want the conditions to stay fairly constant year round, and 50% humidity would feel very comfortable across a wide range of indoor temperatures. When outdoor conditions drop to 10°F or lower, maintaining high humidity indoors can stat to cause problems. Humidity can start to condense on windows, sills, walls, and ceilings. The colder it is outside, the easier it is for windows to pull humidity out of the air. To compensate, our automatic controls will recalculate their internal set point to hold a lower humidity level when conditions are too cold to maintain the normal set point. In general, for every 10° drop in temperature, the control should drop 5% RH from its set point. By setting the control to a higher number, it can delay the temperature at which it begins to lower the set point. At a setting of 6, it waits until the temperature drops 10° more before starting to lower set point. At 7 it waits 20° before the initial drop. This is to try to maintain higher humidity for the longest possible time before starting to drop.
If your home starts to show signs of condensation, fogging or frost on your windows, the set point on the humidifier should be lowered by 1 number to let the house dry out a little more. If the humidity reaches the new level and the condensation disappears, the control is now set to the right level for your home. If there is still condensation at the new, lower level, the control should be lowered by 1 more number to let the house dry out further. This process should be repeated until the windows no longer show condensation at any outdoor temperature.
We appreciate the opportunity to be of assistance.

Can you explain the difference between the Aprilaire Model 700 and Aprilaire Model 700A?

Monday, November 7, 2011 by Aprilaire Team
Consumer question:

I am considering having our local distributor install the Aprilair 700. My understanding is that the 700A is now obsolete. Does the 700 come with the outside sensor that the 700A had. This is a feature I\'m interested in and have received conflicting information on.


Aprilaires' response:

Thank you for contacting Aprilaire.

Good News!! The current 700 is IDENTICAL to the 700A. The reason we dropped the "A" from the model number is because people were becoming confused. Everyone thought that the "A" meant automatic... which it does. But, the controller also could operate like a manual. So, since it is capable of operating both automatically and manually, we dropped the A.

This is the same humidifier, same features, but does have an updated controller. This controller now will allow you to create humidity even when the furnace is not creating heat. It will hold the blower running longer after the furnace is done creating heat. It will do this if the humidifier needs more run time.

I have no return duct, which controller can I use for my new Aprilaire humidifier?

Monday, November 7, 2011 by Aprilaire Team
Consumer question:

I just purchased a model 600 with the automatic humidity control. I do not have a return duct. I was planning on running a 6\" duct from the unit to the inside of the filter box to make the unit work. I noticed the model 60 controller says it needs to be mounted on the return duct. Why can this not be mounted on the wall near my thermostat. I would think if I used stand-offs to allow air to get to the sensor this would work the same. Does the sensor need active air flow to work or would it still register the humidity if mounted on the wall? I would rather use the automatic function rather than the manual mode for obvious reasons.

Aprilaires' Response:

Thank you for your email regarding your model 600A Aprilaire humidifier. The model 60 humidifier control requires air movement to ensure the humidity sensor on the back of the humidifier control gets an accurate reading of the humidity. When mounted to a wall it is difficult for air to get behind the humidistat. Our recommendation would be to install the manual humidistat our model 4655.

My humidifier keeps running unless I turn down the humidistat? Is that correct?

Monday, October 31, 2011 by Aprilaire Team
Consumer question:

Today I set the humidity control just to make sure the unit was ready for winter and once the furnace turned off the fan on the humidifier continued to run, as well as water. When I took the cover off this fall to replace the panel I didn\'t notice anything unusual, but now it just continuously runs unless I turn the humidity control knob below the house ambient humidity.

Aprilaires' response:

If the unit is shutting off when you set the humidity level below the current level of humidity that is consistent with normal operation. With running constantly there could be a couple of issues. The unit could be undersized for the desired humidity level, It could be a wiring issue with the control. Or there could be an issue with the relative humidity sensor. I would recommend turning it up to the minium setting where the unit comes on and then see if the unit shuts off after running for a time. If it does it should be functioning correctly, if it does not. I would call for service.