Attention Aprilaire humidifier owners! First of all, congratulations on making it through a grueling winter. It was cold, snowy and nasty outside, with record-breaking low temperatures and record breaking snowfalls. But thanks to your insight, Aprilaire protected your family and your home from the potential devastation of dry air.
Time to call it a season
With the end of the humidifier season comes a couple of simple tasks to perform. First, be sure you are confident you will no longer require humidification, then follow these easy end-of-season tasks. If you have a bypass-style humidifier, you need to close the bypass damper. Simply turn the handle from the "winter" to the "summer" position. If you have a fan-powered Aprilaire humidifier, no adjustments are required.
Next, if you have an automatic control that is operating in the manual mode, or if you have the Aprilaire manual control, you need to turn the control knob to the "Off" position. This will ensure your humidifier will not turn on during the summer months (when you already have more than enough humidity). If you have an automatic control that is operating in the "Automatic" mode, there is no adjustment required. The outdoor temperature sensor will prevent your humidifier from coming on whenever the outdoor temperature is 60 degrees or higher.
Also, don't forget to call your Aprilaire dealer this fall to perform the annual humidifier maintenance. Your dealer will change your water panel, inspect the water delivery system, and replace any components that are fouled or worn. This indoor air quality (IAQ) expert is trained to keep your Aprilaire humidifier operating at peak performance.
Aprilaire - fresh ideas for indoor air!
My Aprilaire 550 is running every time the furnace comes on and we are not getting an improvement on the low humidity. Our house is about 1200 square feet. Any suggestions? We have installed an energy efficient furnace recently.
Aprilaires' response:
Thank you for contacting us with regards to your model 550 Humidifier. The energy efficient furnace may be running less than the previous model. By limiting the run time of the 550, it's performance over an hour will drop. Is your humidifier fed by hot water or cold water? The 550 will perform better with water temperature as close to 140°F as possible. This will also give you the added benefit of being able to run the humidifier with just your furnace fan. You may need to speak to your contractor to ensure it's properly wired to run with the heat and with the fan, but if it is, you can turn your thermostat's fan switch to the On position, the water provides the heat, and you can get humidity 24 hrs/day or until your desired set point is reached.
I have the same issue. I installed 600A last week. For some reason, the humidifier does not increase the RH above 30% even on the highest setting (7). Our home is 40 years old and only 1500 sq ft. It was installed for automatic operation with the outside air sensor. Any comment to fix this problem
Aprilaires' Response:
One of the most common reason for lack of humidity is lack of humidifier run time do to lack of runtime of the furnace. Another reason is the homes ability to hold the moisture. No matter how well a house is built it breaths. As air escapes from the house so does the humidity. The older a home gets the leaker it gets. So the trick is adding the humidity faster than it is escaping. In most homes the humidifier gets enough run time, but older leaky homes or new homes that are so well insulated that the furnace hardly runs, you will need to extend the humidifiers run time.
If the Model 600 humidifier runs every time the furnace comes on, runs whole time the furnace is on, and gets forced to turn off when the furnace goes off, it is added as much humidity as the furnace is allowing it to. If the humidifier could run longer it would. So if the humidifier is wired to run with the furnace fan, connected to hot water (140 Max), and if you run your furnace fan continually, the humidifier can add up to 16 gallons of water to the air per day.
Some people don't want to run their fan continuously, so another option would be to use the Aprilaire 4851 Blower Activation Relay. This relay will turn on the furnace fan and let the humidifier run as many hours a day as it need to without the fan running continuously.
I am having a similar problem. I just installed a 600A humidifier and the control is set at 7. The 600A humidistat says that the air is at 42% RH, but I have two other humidity meters in the living area that read 33%. Does the 600A humidistat need calibration?
Aprilaires' Response:
Thank you for contacting us with regards to your model 600A Humidifier. The humidistat for this unit does not require calibration. It does, however, only update its display when it detects activity in the furnace, typically the heating mode. If the display constantly shows 42%, regardless of humidity changes in the home, the control may not be wired correctly. If the control does change its display, but stays around 9% apart from the other gauge, then the issue is just a discrepancy between devices. Most gauges will be accurate within 5% to 10% of actual humidity. With the humidity reading at 42% on the humidistat and the control setting at 7, we would expect that the humidifier will be running with each heat cycle of your furnace as long as outdoor temperature is 20°F or higher. If this unit is operating in the manual mode, it should run under these same conditions regardless of outdoor temperature.
I installed a 600A 2 weeks ago in my house. The unit runs for the entire heat call from my thermostat, but my house is having trouble maintaining even 30% humidity. It did raise the RH from around 15% to 30%, but I believe it is trying to go to around 40%. I think I need to increase runtime to get more humidity. I plumbed it to hot water. The way it is currently wired, the R and C are continuously powered and W/G and Cf are tied to the thermostat connection when the thermostat calls for heat. If I were to wire R, C, W/G, and Cf all to constant 24v and then the H outputs to the C and blower terminal on my thermostat connection on my furnace would this cause the humidistat to turn on the blower when more humidity is required? Would this cause a problem with my furnace?
Aprilaires' response:
The way that you describe the current wiring for your humidistat is correct. Please do not change it.
What you are describing below not only will disconnect communication to the humidifier itself, but will damage both the furnace and humidistat controller.
The humidifier will only create the amount of humidity selected on the controller. If you have it set for 30%, then that is the goal it will aim to satisfy. It will not continue to humidify past the selected level.
If you would like to achieve more than 30% humidity, simply select a higher setting. If 30% seems right for your home, you may leave it there.
I have what I was told is an April Air (looks like the 700) that came as part of my high end Carrier central AC/heating system a few years ago. We had an Aprilair before and like this one, but, it's humidity is tied to the heating /AC and the wood in the house (and one guitar) are suffering from it being too dry in here. Everything is set right (humidity maxed out on the thermostat), I hear it go on all the time, and it works right, but we don't have your digital controls to get it up to about 50%. How can I upgrade your system to get more humid air? Luckily Fender fixed my guitar but I was told dry air caused the damage and it has never left this house and a new hygrometer puts the humidity at less then 40%. If I need a new and better AprilAir fine. If this one can be upgraded, that is even better.
Thank you
Aprilaires' response:
Thank you for contacting us regarding the Aprilaire product line. We are happy to assist you with questions relating to the operation and performance of your humidifier. Our humidifiers are designed to provide and control up to 45% relative humidity. Our humidistat controls will only allow the humidifier to provide 45% humidity into the home before it will no longer initiate a call for humidity. If you are trying to maintain more than 45% humidity in the home, we would recommend working through your heating and cooling contractor for a 3rd party control that has a higher limit in regards to humidity control.
In order to get optimum levels of humidification within the home, we would recommend utilizing the humidifier with hot water as the water source, and also to allow the humidifier to operate with the fan operation of the heating system. By utilizing the humidifier with hot water as the water source this will help increase the evaporative capacity for the model 700. You will also get optimum use of the model 700 by wiring this unit to operate in conjunction with the fan for the heating application. What this allows you to do is to humidify the home essentially 24 hours a day. Basically, when putting the fan to the on mode you will be able to provide humidity into the home even though the actual heating system is not actually producing heat at the time. The heat from the water will provide the heat that is needed in the evaporation process. By utilizing the application with hot water and fan operation you will be optimizing the performance of our product and be providing a higher level of comfort within the home.
We would be happy to further assist you with any questions relating to the operation and performance of your humidifier. If there are any further questions regarding your application, please contact us at your earliest convenience.
What are the main differences between the #56 and #58 humidistat? If I want
to use a 6504 zone controller with a #58 humidistat how would I wire it
since there is no + & - terminals? Will the 6504 only work with the #56
humidistat? Any help you can give would be greatly appreciated.
Aprilaires' Response:
The Model 56 and 58 humidistats both work the same way. They are both automatic humidistats that use an outdoor sensor to automatically adjust the indoor humidity level as the outdoor temperature changes. A couple of years ago we added the digital display, a "call dealer for service light", and a "humidifier on" light. These three things are the main differences between the two humidistats.
If you have a 6504 zone controller you would need to use the Model 56. The 6504 firmware hasn't been upgraded to recognize the Model 58.
I hope this answers your questions. Please let us know if you need anything else.
I have an 8346 that runs the heat pump in my home. It works well, but I desire to have control over the temperature offset when the backup (electric) heat comes on. Ideally, I'd like the electric backup to come on only if the actual temperature was more than 3 degrees off of the set temperature. I don't mind the temperature swing and I'd rather save the money.
After talking with someone from Home Depot, this weekend I purchased an 8366 to replace the 8346 and have control the secondary stage offset. However, when I got home, it appears the terminal board for the 8366 is not the same as the 8346. Can you tell me what wires go to which? Or is the 8366 not able to control a heat pump?
Aprilaires' response:
The Model 8366 is not a heat pump thermostat so you will not be able to use it.
The Model 8346 is a heat pump thermostat and you can adjust the differential from 1, 2, and 3 degrees. If you set the differential to 2 degrees the heat would need to fall 2 degrees below the set point before the heat pump would come on. Then it would have to drop another 2 degrees before the electric heat would come on.
The directions for changing the differential are in the operating instruction. Please let us know if you have any other questions.
Last season, the humidifier worked great, no problems. This season, the water just runs through the water panel without distributing out and wicking throughout the whole panel. I've replaced the panel, replaced the distribution tray and still the same thing. Is there something else that can be done? Please advise.
Aprilaires' Response:
The way the humidifier works is; when the furnace comes on, the humidistat calls for humidity and the humidifier turns on. The water solenoid valve opens, water comes up the plastic feed tube and falls into the water distribution tray. Then if the humidifier is level the water will fill up in the distribution tray and will go down the six holes in the tray equally. Then water goes down through the center of the water panel and any water that wasn't evaporated goes down the drain.
The water panels are made out of multiple sheets of slit and expand aluminum. The slits in the aluminum are angled to funnel the water to the center of the water panel. So the water panel should be wet in the center and almost dry on the outside layers.
If you have lack of humidity you may need to increase the humidifiers runtime. The most common reason for lack of humidity is lack of run time. If the humidifier runs every time the furnace comes on, runs whole time the furnace is on, and gets forced to turn off when the furnace goes off, it is added as much humidity as the furnace is allowing it to. If the humidifier could run longer it would. So if the humidifier is wired to run with the furnace fan, and if the humidifier is connected to hot water (140 Max) it can add up to 18 gallons of water to the air per day. You can turn your furnace fan on at the thermostat, let run your furnace fan continually and let the humidifier run as many hours a day as it needs to.
I hope this helps, please let us know if you or your HVAC contractor need any other assistance.
Outside temperature sensor was not installed because the required wiring was not installed. Will 600A unit still operate correctly? What do I need to do because the sensor is not installed?
For normal operation in Winter?
For shut off in Summer?
Response from Aprilaire:
Your 600 should be operating in manual mode. To know this there should be a blue "Manual Mode" clip hanging below the humidistat. When in manual mode, the unit will operate to the setting it is set at until changed. There is a reference guide to show what humidity should be present at a certain temp.. (you will want to look at pages 6-7)
Please review the guide as it will be helpful. When you use the manual mode, all adjustments will be done by you. If you ever decide to change it to automatic mode, the sensor adjusts the indoor humidity in accordance to the outside temperature.
In the summer, simply turn the damper to the "summer" position on the unit to close off air flow.
This unit was installed and worked great for two years. Then I turned it off in the summer and forgot to turn it back on for the last two years. Now, I changed the filter and cleaned everything out. However, it doesn't seem to work. The humidity in my house is 10.
I hear the water turn on for a few minutes at the beginning of the heat cycle. Then it turns off. When I look at the filter, it is only wet at the bottom 1 inch. The rest is dry. The water seems to go into the first float chamber, but doesn't go into the second chamber. I don't see what is preventing the water from moving over.
I had the technician, who installed it, come and look at it. He suggested changing the filter and isn't sure what is wrong. He hasn't been doing this humidifiers for a while. He thought that it might be the water level sensor assembly. However, no one seems to have this part in stock. I will have to order it and get it installed. Then, I might find out that is not what is wrong, and I will have paid more money to have the wrong thing fixed. I already spent $85 for the technician and $45 for the filters. I really want to get it fixed. Can you make some recommendations?
Aprilaires' Response:
Thank you for contacting us with regards to your model 400 Humidifier. Based on the information you provided, the humidifier is working properly. The water should fill from the top, trickle down across the water panel. Verify that you are using a Genuine Aprilaire Stock #45 Water Panel. The water will only raise the float in the right-hand chamber. The left float is an emergency overflow. Water should not fill that chamber unless the first fails to shut off the water. The fact that the water does shut off indicates that the sensor is working properly. The water panel should then wick water up from the reservoir and it will evaporate as it rises.
Water shouldn't rise very far before it evaporates, but most of the water will rise up through the center of the pad, as opposed to the outer layer of material. As long as the humidifier refills at the beginning of, or during, each heat cycle, the humidifier is working. For a test of how well it's working, please do an Evaporative Test. This can be done using a measuring container and a timer.
The evaporative rate of the Model 400 is based entirely on the temperature of the heated air and the amount of run time of your furnace. The performance values are based on 120°F air and 50% run time. This should give 0.70 gal/hr.
It's not clear from the information you provided how long the humidifier has been running with your home at 10% RH. Did it start at 10% and it hasn't changed, or was it higher and has since fallen, or was it lower and has since risen? Humidity can take a while to change, so we would look at the trend of the humidity over time, if it's going up, down, or staying the same. At this time, it doesn't make sense to replace the water level sensor from a troubleshooting standpoint.
For some reason, the humidifier does not increase the RH above 20% even on the highest setting (7). Our home is 4 years old and under 3,000 sq ft. It was installed for automatic operation with the outside air sensor. Any idea about what the problem could be?
Answer:
We would suggest that you contact the HVAC contractor who installed the humidifier and have them verify if it is working properly. If you want to trouble shoot it yourself you can call our technical support department at 1-800-334-6011 Monday - Friday from 7:00 AM to 5:00 PM central time) and we would be glad to help you determine if it is working properly.
Once we can determine wether or not the humidifier is evaporating .75 gallons per hour, we can take the next step. If it's evaporating less than .75 we should be able to find out why and fix it. If it is evaporating properly but you still don't have enough humidity in your home, we need to make the humidifier run longer to add more humidity.
The most common reason for lack of humidity is lack of run time. If the humidifier runs every time the furnace comes on, runs whole time the furnace is on, and gets forced to turn off when the furnace goes off, it is added as much humidity as the furnace is allowing it to. If the humidifier could run longer it would. So if the humidifier is wired to run with the furnace fan, if you run your furnace fan continually, and if the humidifier is connected to hot water (140 Max) the humidifier can add up to 18 gallons of water to the air per day.
I hope this helps, please let us know if you or your HVAC contractor need any other assistance.
I have a LOUD knock when the Solenoid valve closes sometimes. It is happening more often now. I have had Arrow Heating who installed the unit out but they were unable to stop the noise. They turned down the water flow but we still have the problem. The valve closes OK sometimes but other times it makes a loud knock when it closes which can be heard in the whole house. I understand there will be a small knock when it closes. Is there something I can do?
Answer:
A humidifier may cause a "click" or "bang" sound for one of two reasons.
1) Water, as it moves through the solenoid of the humidifier, can build up pressure and create noise. Usually water hammer is a repeated bang. To see if water pressure is the issue, turn off the water to the solenoid. If the noise stops install a "pipe silencer" or extra coiled water supply line to the humidifier to reduce the noise generated by the pressure.
2) The solenoid itself will create an audible "click" as the humidifier turns on and off. This "click" may be magnified to sound like a "bang", by the ductwork or the proximity of the humidifier to the living space. Usually a solenoid will create only one "bang" when the solenoid opens and one "bang" when the solenoid closes. Isolating the solenoid from the ductwork with foam insulation or remote mounting the solenoid will be necessary. Please note; If the solenoid does produce a repeated "bang" when it opens or when it closes, the wiring should also be looked at to eliminate the repeated opening and closing of the solenoid.
Single digit outdoor temps, twenty degrees here, forty degrees there. The outdoor temperature has been fluctuating all over the place. What does this mean to you? Well, if you have a whole-house humidifier with a manual control, it probably means you turned your control down when it got really cold outside because condensation was pouring down your windows. It probably also means you forgot to turn the control back up once it warmed back up outside. Sound familiar?
Aprilaire automatic humidifier control to the rescue
The Aprilaire humidifier with premium digital control works in conjunction with an outdoor temperature sensor to automatically adjust your home’s indoor relative humidity (RH). This automatic adjustment protects your home from moisture damage when the mercury dips, as well as providing the maximum comfort when the outdoor temperature comes back up. We call it the "set it and forget it" control.
Call your Aprilaire dealer and ask about a whole-house humidifier with premium digital control. If you already have a whole-house humidifier, but have manual control, ask your dealer to upgrade you. You'll be glad you did.
Aprilaire - providing you maximum comfort and protection, automatically, for over 50 years.
We received a question from Ancha:
"HI, I moved to a new house, my Aprilaire 760 humidifier works, but makes sound (I mean, when it works, the sound is really uncomfortable upstairs). Is it supposed to work like this? I mean, I will buy a new unit and install, but are humidifiers supposed to make so much noise? Or can I fix this noise in the existing unit? Thank you for reply"
Aprilaire response
The Model 760 is a fan-powered humidifier, meaning that there is an on-board fan that draws air across the evaporator water panel to achieve maximum humidification. Fans do create sound, however, the sound is generally not audible over the blower of your HVAC system. It can be noticeable if you have a variable speed HVAC blower, and you are operating on low speed while humidifying. Even then, however, it should not be an "uncomfortable" sound.
That said, it sounds like the fan motor in the humidifier may need some attention. Please contact your local Aprilaire dealer, who can diagnose the problem and offer you the best solution.
Thank you for your question and thanks for choosing Aprilaire!
We received a question from Jinho regarding his Aprilaire humidifier:
"Looking at the wiring, it appears the R - C and W/G - Cf wires go to the respective furnaces R - C(ommon) and Humm - C(ommon) connections. Is there any way to wire it so that it comes on any time there are necessary relative humidity changes?"Aprilaire response
The wiring configuration you have limits the humidifier to operating only during a heat call. There are a couple of options your dealer can look at to increase your humidifier run time and corresponding level of relative humidity.
One is to wire the control through the EAC terminals (if your furnace has them). EAC terminals are 120V, requiring your dealer to wire through a transformer. This would allow you to humidify any time the HVAC blower is operating. So, if you wanted to humidify outside of a call for heat, you could flip your thermostat fan setting from "Auto" to "On" and the humidifier would operate, provided there is a call for humidity.
Another option is to install the Aprilaire Blower Activation Relay, part number 4851. With this device installed, the HVAC blower is automatically activated on a call for humidity, with no thermostat interaction on your part.
Thank you for the question, Jinho, and thanks for choosing Aprilaire!
With the recent cold snap, did you notice any condensation on your home's windows? If you have either a portable humidifier or a whole-house humidifier with manual control, odds are you had water pouring off your windows when the mercury dipped way down. This forced you to either turn down or turn off your humidifier to prevent damage that comes from this excess moisture.
Question - did you remember to turn your humidifier back on once the weather warmed back up? Chances are you did not. Maybe you did, but probably not until you began to suffer some or all the ailments that come with dry, winter air: stuffy nose, scratchy throat, and itchy skin, just to name a few. What can you do to ensure your home is properly humidified, day after day, regardless of outdoor temperature? The answer is simple - install an Aprilaire humidifier with premium digital control.
Automatic control is the key
The Aprilaire premium digital humidifier control works in conjunction with an outdoor temperature sensor, automatically raising and lowering the relative humidity (RH) in your home to achieve the optimal level of humidification. This protects your home from the damage that can come from excess RH while still providing the comfort and health that comes from properly humidified air. This "set it and forget it" feature means you'll never have the hassle of raising and lowering your control setting again.
Call your local Aprilaire dealer and schedule the installation of your Aprilaire humidifier with premium control today. If you already have a whole-house humidifier but do not have automatic control, ask your dealer about upgrading. You'll be glad you did.
Aprilaire - Protecting you and your home, automatically, for over 50 years!
A question from E. Roth:
"Pls explain difference between model 600 and 700. Do they both work in same way and mount in same way? I currently have a kennmore 3000 mounted on plenum at supply side. It is wired into fan switch on furnace. Water supply valve not working properly and I can no longer get parts. My house is approx 4000 sq ft."Aprilaire Answers
That's a great question. The Kennmore 3000 is a reservoir-style humidifier. A media wheel picks up water from the water tank, and this moisture is transferred from the wheel via air flow from your HVAC system. This type of humidifier requires a lot of maintenance to prevent mold, mildew and other nasty things from growing in the tank and on the wheel and getting into your home’s air stream.
The Aprilaire 600 and 700 Series humidifiers utilize flow-through technology with no standing water. This highly efficient method provides maximum evaporative performance and only requires annual maintenance.
The 600 Series humidifier is a bypass humidifier, utilizing the pressure differential between the return and supply plenums to drive air through the water panel evaporator, where moisture is picked up and transferred throughout your home. The 600 can be mounted on either the supply or return with equal effectiveness.
The 700 Series is a fan-powered humidifier, utilizing an on-board fan to move the air across the water panel evaporator. It is typically installed on the warm air supply. The 600 Series is rated for a 4,000 square foot, tightly constructed home. The 700 Series is rated for a 4,200 square foot, tightly constructed home. Both are available with manual or premium digital control. We recommend the premium digital control for maximum comfort and protection. Your local Aprilaire dealer can recommend the right unit for you, based on your home’s needs and your current HVAC requirements.
Thank you for your questions and thank you for considering Aprilaire!
The Aprilaire Humidifiers are evaporative humidifiers. Aprilaire humidifiers are available as a bypass or power model. A bypass humidifier gets its air movement through the Water Panel® by the differential pressure between the supply (hot air) plenum and the return (cold air) duct. The supply plenum is under positive pressure and the return duct is under negative pressure.One of the advantages of a bypass humidifier is that it can be installed either on the supply plenum or on the return duct with equal effectiveness. No matter which duct the unit is mounted on, the airflow always goes from the supply to the return through the humidifier.
A power humidifier gets its air movement through the evaporative Water Panel® from an internal fan. The fan in a power humidifier draws air from the supply plenum into the unit, through the water panel. The humidified air is then discharged out the slots on each side of the base of the unit and back into the supply plenum, where it is distributed to the home by the HVAC blower through the ductwork of the system. The power humidifier is designed to be installed on the supply plenum, however may be installed on the return duct provided a hot water supply is used.
Aprilaire humidifiers are designed to operate in conjunction with your furnace blower motor. Most installers wire a humidifier to operate when the furnace is calling for heat. Each Aprilaire unit uses the same high-quality components. As a result both the bypass and power type humidifiers will effectively humidify the same home. We offer both types due to the square footage of a home, type of heating and cooling system, along with the space available for installation.
Your licensed heating and air conditioning contractor is the best person to recommend which Aprilaire is best for your application is since they have first-hand knowledge of your heating and cooling system.
A question from Perry in Chicago
"I have a question. I have an old Aprilaire humidifier attached to my home's furnace. There is a dial on it that says either dry (20 or lower) or moist, 40 or higher. So what does this mean? the label says relative humidity, but does that mean the relative humidity outside or inside my house? I live in chicago, and its 0 degrees today and my basement windows have so much moisture on them, that they have iced over! I had the RH dial set to DRY, or 25-30. Help!"
This is a great question, Perry. From your description, it sounds like you have a manual humidifier control, which means you have to change the setting on your control as the temperature changes outside. Your home can achieve a higher relative humidity (RH) when the outside temperature is higher without moisture forming on your windows. However, when the outside temperature drops, like it recently did in the upper midwest, you will form moisture on your windows if you don't dial down the control.
| Outside Temperature | Recommended RH |
| +40F | 45% |
| +30F | 40% |
| +20F | 35% |
| +10F | 30% |
| 0F | 25% |
| -10F | 20% |
| -20F | 15% |
As you can see from the table above, at 0 degrees F, the recommended RH is 25%. However, this can vary from home to home, depending on the level of insulation in the walls, type of windows, how tight your home is, etc. With the extreme temperatures you are experiencing, your control should be down to almost it's lowest level.
Automatic control removes the hassles
To eliminate the hassle of constantly adjusting your control, I would suggest you call your local Aprilaire dealer and ask him to upgrade you to an Aprilaire automatic digital humidifier control. It works in conjunction with an outdoor temperature sensor to adjust your indoor RH according to the outside temperature. After the initial setup, you never have to adjust it again. We call it the "set it and forget it" control. The control also tells you your indoor RH, when to change the water panel and if service is required.
Thanks for the question, Perry, and thanks for buying Aprilaire products.
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