Prepare for the Allergy Season by Controlling Air Purity on Your Terms

Friday, April 11, 2014 by Aprilaire Team

After such a long, hard winter, a pleasant, sunny spring may be a dream come true for many of us, but it could be a nightmare for allergy sufferers. That's because pollen-producing plants like the same kind of mild, calm weather that most of us do.

Even if we can't predict how bad the pollen will be outside, there are steps you can take to reduce pollen indoors.

Most experts recommend a strategy of avoidance to reduce indoor allergies.  The American Academy of Allergy, Asthma & Immunology (AAAAI) suggests that homeowners consider such measures as:

  • Covering mattresses and pillows in non-permeable covers
  • Removing carpets and curtains from bedrooms
  • Having non-allergic members of the household do the vacuuming
  • Keeping pets out of the bedroom
  • Limiting outdoor activities during days with high pollen counts
  • Keeping windows closed (at home or in the car) to keep pollens out
  • Take a shower after coming indoors; otherwise, pollen in your hair may bother you all night

An effective strategy to trap airborne pollen and other particles is with the use of a high efficiency air cleaner installed in the home's heating and cooling system.  A whole-home solution like the Aprilaire Air Cleaner removes up to 99% of pollen.

To get the most out of air cleaning, Aprilaire offers homeowners an air cleaning control that allows them to actively clean the air in their entire home based on personal preference and event triggers. A simple-to-program thermostat features Event-Based™ Air Cleaning with these settings to allow homeowners to customize cleaning based on their needs:

  • Constant Cleaning:  Air is cleaned 24 hours a day, seven days a week
  • Automatic:  Cleans for 30 minutes every hour
  • Event Clean:  Cleans for three continuous hours
  • Allergies:  Cleans continuously for a 24 hour period

Event-Based Air Cleaning also provides other conveniences such as indicators that air cleaning is taking place as well as maintenance reminders.

As we weather an unusually long allergy season this year, there is hope and help! Maintaining a cleaner home environment as well as the recommendations from AAAAI and other allergy professionals can help sufferers cope with aggravating day to day symptoms.

Aprilaire has been a brand leader in the indoor air quality industry for over 60 years.  The company designs, develops, manufactures and distributes whole-home indoor air quality products that provide comfort, health, energy efficiency, and the protection and preservation of the home.  Visit to learn more about the benefits of whole-home air cleaners, Event-Based™ Air Cleaning, and total comfort control solutions to air purity, humidity, fresh air and temperature.

Remember when school classrooms consisted of desks, pens and paper and textbooks?

Friday, October 25, 2013 by Aprilaire Team

Remember when school classrooms consisted of desks, pens and paper and textbooks? Or crayons, construction paper and glue? Or how about slide rules? With all the gadgets available today, what steps do you take to ensure your child is learning and not goofing around? (OK, if you’re a student, we hope you’re learning. You can goof off at home!) This article from WebMD offers back to school parenting advice in a wired world:

No water is getting to my humidifiers' feedtube, please help!

Monday, June 10, 2013 by Aprilaire Team
Consumer question:

My humidifier recently stopped working. No water is being feed through to the unit. When I place it in test mode I get an R1 error code and flashing blue lights. Please let me know what I need to do to fix my unit asap.

Aprilaire's response:

Thank you for contacting us regarding your model 600M humidifier. The R1 that you see on the screen after the test mode simply means the control is a revision one control. This revision indicator has no effect on the operation of the control or the humidifier. The blinking blue lights with the R1 simply tells us that the test mode is over and the control knob is still in the test position. If left in test, the control will not turn the humidifier on at all.

If water flows through the unit while in test, then it may not be running because of the current level of relative humidity. Typically when the solenoid operates in test, the system is working fine. If the control is reading a relative humidity level at or above 45%, the unit will not operate outside of test. Also, there is an accuracy differential of +/- 5%. For example, it is possible that the control displays 40% but still does not operate on the highest setting.

Additionally, if you are using the outdoor temperature sensor for automatic operation, the outdoor temperature may be the cause for the humidifier to not run. If the outdoor temperature is at or above 55 degrees the control will not turn on the humidifier.

Furthermore, to better understand why your unit is not operating, 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.

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

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.

We installed this Humidifier last fall and it is located within the garage area...

Friday, March 1, 2013 by Aprilaire Team

Consumer question:

We installed this Humidifier last fall and it is located within the garage area, mounted on a forced air gas furnace.
the problem we are having is the humidistat says it is 50% humidity and if we check the area that the control is in that is true. the problem is we want 40% in the working area that is being treated and are only reading 34% in the area where it is needed? Can you advise?


Aprilaires' response:

Thank you for contacting us. When the humidistat is mounted on the return air duct the humidistat is taking an average humidity reading from the whole home. If you have any rooms where heat vent is closed, but the return vent is still open can affect the reading that the humidistat is getting from the home. By lowering the temperature in a room you also increase the humidity in the room, and this can affect the reading that the humidistat is getting from the home.
You would need to contact your installing contractor to discuss possible solutions to your humidity problem. The first thing that would need to be checked is the actual humidity reading is in the duct at the same location as the humidistat and the area around the humidistat to see what reading you are getting. This would need to be done to see if you are getting an accurate reading of the humidity from the humidistat. Air around the humidistat might be leaking into areas around the humidistat and affecting the reading that the humidistat is getting.

One possible solution is by replacing the automatic humidistat with a manual humidistat mounted in the living space to get a better average humidity level for the home than your current installation could provide. If you have any other questions please contact us at 800-334-6011. Thank you


Is there a way to regulate the water control on the Aprilaire model 700 humidifier?

Thursday, February 28, 2013 by Aprilaire Team
Consumer question:
Is there a way to regulate the water control? I get a steady stream coming out of the drain line. Thank you!
Aprilaires' response:
Thank you for inquiring about your Aprilaire model 700 humidifier.

Your humidifier, when wired properly, will allow a stream of water to flow through the water panel only during the humidification cycle. If the humidistat is not requesting humidification, then the water should not be running through to the drain. The water flow rate into the model 700 is fixed to 6 gallons per hour, during the humidification cycle. The water flow down the drain depends on the evaporation effect within your environment, estimated between 4 to 4.5 gallons per hour.
Aprilaire - Division of Research Products Corporation
Hours Monday - Friday
7:00 a.m.- 5:00 p.m. CST


Can I run and Aprilaire 600 in manual mode?

Tuesday, February 19, 2013 by Aprilaire Team
Consumer question:
Aprilaires' response:

Dear Randy,

Thank you for your email regarding your model 600 Aprilaire humidifier. Your model 600 can be set up as an automatic or manual control. In automatic there is an outdoor sensor connected to the control which will allow the control to automatically adjust the humidity level as the outdoor temperature changes. In manual mode you will need to adjust the humidifier control as the outdoor temperature changes. If not, you may over humidify your home. If you choose to run in manual mode simply remove the outdoor sensor from the terminals labeled odt and connect the manul model sensor instead.

Thank you for giving us the opportunity to be of service


Blower Motor Cycling Issue

Monday, February 18, 2013 by Customers Sharing Stories

Consumer feedback:

I have the Model 700 with the Model 58 humidistat. The problem I'm having is that the humidistat is callingtne furnace to start the blower motor I guess because the humidity has fallen below what it needs to be. However, the blower motor comes on for like 10 seconds and the shuts off. It will repeat this cycle 100 times a day so I have to turn the humidistat off. It generally only does this during the day because the thermostat is set to a temp that generally doesn't require heat. The HVAC guy has replaced the humidistat already with no success. My furnace is an Amana prane model. What's going on with this? Thanks

Name: Ken
City: Middletown
State: MD


Aprilaires' reponse:

Dear Ken,

Thank you for contacting us with regards to your model 700 Humidifier. Based on the information provided, it’s not clear how this humidistat has been wired. Normally, the model 58 humidistat does not have the ability to operate your furnace fan without an additional relay. It’s possible that this relay has not been wired properly. We would recommend that you have your HVAC guy contact us when he’s next on-site. We can provide troubleshooting assistance by phone.

We look forward to assisting you with this issue.

1-800-334-6011 Ext.6172
Call Center hours are M-F, 7 a.m. to 5 p.m. CST

Replacing an existing Aprilaire model 760 humidifier, couple of questions...

Monday, February 4, 2013 by Aprilaire Team
Consumer question:
I want to replace the existing 760 model, however, due to the size to the furnace, it cannot be any larger than the existing unit. The current model 700 is about 2 inches higher so I can use it. What model would you suggest I use and what if any issues will I run into.
Aprilaires' response:

Thank you for contacting us regarding the replacement for you model 760 humidifier. If you are unable to replace the 760 with the 700 then you could use the model 600. The 600 is a bypass humidifier which operates slightly different than the 760 or 700. Where the 760 and 700 are power humidifiers that use an internal fan to add humidity to the air in the duct work, the 600 is a by pass unit that utilizes the HVAC blower to add the humidity to the air.

The 600 has similar capacities to the 700 and can provide humidity on a tight home with 8 foot ceilings of up to 4000 square feet.

Additionally, due to the differences in the installation, as well as the wiring of the humidistat control, we recommend the installation be done by a licensed HVAC contractor. When installed by a licensed contractor, the units come with a 5 year warranty beginning on the date of installation. If you choose not to use a licensed contractor you risk voiding the 5 year warranty.

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.
Call center hours are M-F 7am-5pm CST



When should my Aprilaire model 700 humidifier run?

Thursday, January 3, 2013 by Aprilaire Team
Consumer question:
Since my model 700 was installed last winter, I've noticed it sometimes runs even if the heater isn't running. Also, sometimes, if the heater is running, the humidifier does not. It seems to run completely independently of whether the heater is running or not. Is this normal?
Aprilaires' response:
Thank you for contacting us. The humidifier does not regularly run independent of the furnace when wired to turn on and off with the furnace heat call. If you turned the humidistat down when the humidifier was running, does the humidifier turn off? If the humidifier stays on when the humidistat is turned down, then you would have a bad solenoid. If the humidifier turns off then you have a good humidistat and good solenoid.

Do you have a digital humidistat that you are controlling the humidifier with? The digital humidistat has a blower activation switch on it and you might have that in the on position. Turning the blower activation switch to the off position should solve your problem of the humidifier running in these different times.

If you have a manual control to wired to the humidifier, then you would need to have your service contractor trouble shoot the current sensing relay that would be wired between the humidistat and humidifier.
If you have any other questions please contact us at 800-334-6011. Thank you


Does basement humidity have affect on my humidifiers operation?

Monday, December 31, 2012 by Aprilaire Team
Consumer question:
Aprilaire model 500 humidifier installed on 2-stage 95% furnace. Sensor is located inside cold air return from house. Cold water to humidifier. Does basement humidity have affect on humidifier operation ie. humuduty levels in residence. Have dehumidifier in basement set at 40%. On setting five humidity in residence is 32-35% Setting 6 36-39% Is this normal? I think it should be higher. Humidifier works in test mode. Insight?
Aprilaires' response:

Thank you for your email regarding your model 500 Aprilaire humidifier. Your Aprilaire humidifier control measures the humidity in the cold air return which is the air coming back to your HVAC system from your entire home. A dial setting of 5 would be equivalent to an indoor relative humidity of 35% anytime the outdoor temperature is 20F or above and the indoor temperature is 70F. A dial setting of 6 would be equivalent to an indoor relative humidity of 40% anytime the outdoor temperature is 20F or above and the indoor temperature is 70F. We design our humidifiers to maintain 35% anytime the outdoor temperature is 20F or above and the indoor temperature is 70F. The actually humidity a specific home will vary due to the tightness and cubic footage of the home as well as the runtime of your HVAC system. In addition a humidity level higher than 35% may cause damage to home. This is because as the temperature outside drops, the air in your home may not be able to maintain a humidity level above or even equal to 35%. If the humidity level is too high for the current outdoor conditions, the result is condensation on your windows. This is described in the attached owners manual. Based on the information you provided it appears your mode 500 is performing properly.


Should my Aprilaire humidifier run ONLY when my furnace is running?

Monday, October 29, 2012 by Aprilaire Team
Consumer question:
I have an Aprilaire model 700 and I assume it's normal to turn on my heater's blower in automatic mode to raise humidity? When I turn it down from 5 to 3, the blower doesn't turn off. Is that normal?
Aprilaires' response:
Thank you for contacting us regarding your model 700 humidifier. When installed and wired properly, the humidifier should only turn on after the blower has been activated due to a heat call or fan call from the thermostat. If your control has the optional blower activation function, it may extend the blower and humidifier run time after the heat call has been satisfied. However, if you are using the blower run extension, it should turn the blower off if you lower the humidity level. We may need more information to fully understand your particular situation.

Additionally, to better understand the functionality of your unit, you have the option to call our technical support department at 1-800-334-6011 to discuss it with one of our technicians over the phone.

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.

Call center hours are M-F 7am-5pm CST


Mechanical Ventilation

Thursday, October 18, 2012 by Aprilaire Team

The Need for Mechanical Ventilation

History of Ventilation in Houses
Houses need to have an indoor/outdoor exchange of air to replenish oxygen used by the occupants and to remove pollutants generated by breathing, household activities and emissions from building materials and furnishings. For many years, houses were constructed without mechanical ventilation systems and relied on air leakage through the building envelope to provide this indoor/ outdoor air exchange during the winter months.

In the past, this natural form of ventilation worked fairly well. Houses built before the 1960s tended to be quite leaky and pressure differences between the inside and outside, caused by wind or temperature difference, were sufficient to provide a significant amount of air exchange most of the time. However, a leaky building envelope does not always guarantee adequate air exchange. The movement of air requires both a pathway (e.g., a leak) and a pressure difference, and even a leaky house will experience periods when there is no indoor/outdoor air exchange. These periods are most likely to occur during the spring or fall, when winds are light and there is little or no indoor/outdoor temperature difference that can create a stack effect. The leakier the house, however, the less frequent the periods of inadequate air exchange.

Since most fuel-fired systems consume air from the house, and this air must then be replaced by leakage from outdoors, the operation of fuel-fired systems promotes some indoor/outdoor air exchange. The chimneys associated with these systems also provide a major leakage point, thus promoting air exchange even when the heating system is not operating. As well, a chimney tends to raise the level of the neutral pressure plane, thus reducing the outward pressure difference across the building envelope and, with it, the potential for interstitial condensation (i.e., condensation that occurs within the building envelope) caused by air leaking out of the house.

In houses built prior to the 1960s, the amount of air exchange provided by leakage was generally regarded as sufficient. But in the '60s, a number of factors changed this picture, including the increased use of electric heating in houses. Unlike fuel-fired systems, electric heating systems do not require the replacement of air, nor do they require chimneys. Consequently, electrically heated houses have a greater tendency to experience high humidity levels, interior surface moulds and interstitial condensation.

In the early 1970s, in response to these problems associated with electrically heated houses, Canada Mortgage and Housing Corporation (CMHC) took the step of requiring all NHA-financed electrically heated houses to incorporate exhaust fans, a requirement that was eventually incorporated into the National Building Code. By the mid-70s, these problems had became so apparent that CMHC contemplated not allowing electric heating in houses financed under its National Housing Act mortgage insurance program.

In addition to the increase in the use of electric heating, the 1960s brought the construction of houses that were much more airtight as a result of new products and practices, which included the substitution of panel sheathings, such as plywood and waferboard, for board sheathing; the replacement of paper-backed insulation batts by friction-fit batts and polyethylene film; improved caulking materials; tighter windows and doors; and more efficient heating systems.

When the energy crisis developed in the early 1970s, considerable emphasis was placed on reducing air leakage in order to conserve energy. The use of electric heating systems was encouraged and higher efficiency furnaces were developed further reducing airchange rates in buildings. This trend towards greater airtightness and higher efficiency furnaces gave rise to concerns that the exchange of air in houses by natural means might be insufficient in some instances to provide adequate air quality thus increasing the risk of health problems among the occupants. Condensation problems resulting from higher humidity levels were also a concern.

How Much Indoor/Outdoor Air Exchange Is Necessary?
The air-change needs of houses are not uniform. Not only do they vary from house to house according to the number of occupants, and the presence and strength of various pollutant sources, but, for any given house, they also vary with time as occupants come and go, and pollutant sources wax and wane. Nevertheless, ASHRAE Standard 62, Canadian Standards Association Standard CAN/CSA-F326 and the National Building Code of Canada (NBC) have all established levels of air change that can be expected to meet the peak or near-peak needs of a majority of normal households. (The latter two are based to some extent on ASHRAE Standard 62.)

All three approaches suggest an air change rate of about 0.3 air changes per hour (ach). This is the level of air change used internationally as the norm in terms of analyzing the success of various ventilation schemes. Again, it is recognized that few, if any, houses require constant air change at the rate of 0.3 ach. However, if a house is so tight that leakage fails to provide this level of air change for significant periods of time, it is likely that many such periods of shortfall will coincide with periods when this level of air change is required. When this happens, poor indoor air quality, high humidity, surface moulds and interstitial condensation can result.

How Airtight Are Recently Built Houses?
In 1989, a study to determine the airtightness of recently constructed houses in various regions of Canada was conducted. Airtightness was measured by carrying out fan-depressurization tests on nearly 200 houses throughout the country. The test results were analyzed to estimate the indoor/outdoor air change rate that could be attributed solely to the air leakage likely to be experienced by each house over a typical heating season. The results of the study allowed the researchers to make the following predictions:

  • More than 70% of the surveyed houses would have an average air-leakage rate of less than 0.3 ach over the entire heating season.
  • Almost 90% of the surveyed houses would have at least one month during the heating season when the average air-leakage rate was less than 0.3 ach.
  • Virtually all of the surveyed houses (99%) would have at least one 24-hour period over the heating season in which the average air-leakage rate was less than 0.3 ach.

These results seem to indicate that a majority of houses being built in Canada using normal construction practices are close enough to being airtight that air leakage through the envelope cannot be relied on to provide the rate of air change deemed necessary to maintain adequate indoor air quality in a typical household. While the rate of air change through the building envelope may be adequate most of the time, it may not be all of the time. Therefore, to ensure that a satisfactory rate of air change is attainable at all times throughout the heating season, these houses must be provided with mechanical ventilation systems.

Characteristics of an Ideal Mechanical Ventilation System

Currently available technology is not able to provide an ideal mechanical ventilation system for houses. But before looking at the methods of mechanically ventilating houses that are available today, it is helpful to identify the characteristics of an ideal system:

Operate when needed
The system would operate whenever additional indoor/outdoor air exchange is needed and would do so without the need for occupant intervention.

Operate only when needed
This is important since a mechanical ventilation system has costs associated with it — the cost of the electricity to run it and the cost of heating the outdoor air that the system brings in. (The latter can be reduced by incorporating heat-recovery capabilities in the system, but cannot be eliminated altogether.) Therefore, the system should not operate during those periods when no indoor/ outdoor air exchange is required. The length, timing and frequency of such periods vary from household to household. Air exchange is not required when:

  • there are no occupants in the house
  • there are no activities or processes underway that generate pollutants
  • there is sufficient air exchange due to wind or stack effect to meet the household's needs.

Provide needed amount of air exchange
The system would be able to deliver enough outdoor air to meet the probable maximum needs of the household. It would also be capable of modulating delivery so that it did not deliver more outdoor air than required at times of reduced need. A system that does not have this capability is likely to provide too much outdoor air most of the time it is in operation, resulting in excess energy costs and low humidity. As well, a system that is unresponsive can annoy the occupants, possibly to the point that they simply turn it off altogether.

Distribute outdoor air where needed
It is not enough that the mechanical ventilation system change the air in the house as a whole to meet the standard of 0.3 ach. The system must also be able to deliver the outdoor air to those parts of the house where the occupants are likely to spend most of their time — the living room, the kitchen and the bedrooms.

Be quiet
The system would be quiet enough so that the occupants would not be tempted to turn it off to reduce noise.

Not interfere with other systems
There is significant potential for mechanical ventilation systems to interfere with the operation of other systems, such as certain types of fuel-fired heating systems. Under these circumstances, if the ventilation system creates a high negative pressure in the house, the products of combustion (which can be harmful to the occupants) can spill into the house rather than flowing up the chimney to the outdoors.

Not interfere with the building envelope
The system would not create significant positive pressure in the house since this could drive humid air from the house through the building envelope, resulting in interstitial condensation.

Demand-Controlled Ventilation

The first two characteristics of the ideal mechanical ventilation system described above are related to the issue of control. A system that embodies these characteristics is known as a "demand-controlled ventilation system." Such a system would ideally be controlled by an array of sensors — one for humidity and one for every possible pollutant that the ventilation system would have to respond to, including carbon monoxide, carbon dioxide, formaldehyde, volatile organic compounds, etc. The system would bring in outdoor air and/or extract indoor air until all of these sensors determined that specific pollutants were at, or below, predetermined safe levels. Whenever a sensor detected a pollutant above its safe level, the ventilation system would operate.

A less-than-ideal demand-controlled ventilation system would have at least one sensor. For example, many ventilation systems are controlled by dehumidistats: the system operates until the dehumidistat has determined that the humidity in the house is at a safe level. Excess humidity is one of the main reasons that ventilation is required, but not the only one. The amount of ventilation required to control humidity may not be sufficient to control other pollutants since this depends on the activities of the occupants, on the relative strengths of other pollutants and on the level of humidity.

Carbon dioxide (CO2) sensors are sometimes used to control ventilation systems in large buildings, and this technology is just now becoming available for residential use. Increasing CO2 concentration is usually a good indicator of decreasing air quality but it may not be adequate in cases where there are unusual pollutants, such as those generated by certain hobbies.

The ideal system requires the full array of sensors mentioned above. However, at present this ideal is not attainable because:

- there is insufficient knowledge and information to determine

- which pollutants should be monitored, and

- what the acceptable levels for a particular pollutant

- practical, reliable and economical detectors for all pollutants of concern are not available.

While research and development is underway in many countries to try to address these issues, breakthroughs are not expected in the near future.

For a discussion of current approaches to mechanical ventilation systems for houses, please see Construction Technology Update No. 15.


1. ASHRAE 62-1989, Ventilation for Acceptable Indoor Air Quality. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, GA.

2. Standard CAN/CSA-F326-M91, Residential Mechanical Ventilation Systems. Canadian Standards Association, Etobicoke, ON.

3. National Building Code of Canada, 1995. Canadian Commission on Building and Fire Codes, National Research Council of Canada, Ottawa.

4. 1989 Survey of Airtightness of New, Merchant Builder Houses. Haysom, J.C., Reardon, J.T., and R. Monsour. Indoor Air '90: The Fifth International Conference on Indoor Air Quality and Climate, v. 4, Toronto, 1990.

5. Residential Air System Design. Heating Refrigerating and Air-Conditioning Institute of Canada (HRAI), Islington, ON, 1986.

6. Complying with Residential Ventilation Requirements in the 1995 National Building Code. Canada Mortgage and Housing Corporation, Ottawa, 1996.

7. Airtightness and Energy Efficiency of New Conventional and R-2000 Housing in Canada, 1997. Canada Centre for Mineral and Energy Technology, Natural Resources Canada, Ottawa

Faulty wire connection?

Wednesday, October 17, 2012 by Aprilaire Team

Consumer question:

Hi: I have the 8570 thermostat pn 61000229 rev c with a 700a humidifier; ADHC model 58; 61000501 rev b.
The adhc is wired to the 8570 for activation. The supplied outside sensor is also used. It works but intermittenly the 8570 screen goes blank while operating and causes the adhc "call dealer for service" light. the E4 code appears on the adhc. I had the heating tech out for annual service and could not find anything wrong. The only other symtom that I noticed was it occurs in the temp range freezing or above. During continous freezing weather, it did not seem to need to be reset as much.
I have rechecked the wiring between the 8570 and adhc and it is correct. The intermitten screen blank on the 8570 makes me believe that either the unit is faulty or an intermitten power loss.  Any thoughts?


Aprilaires' response:

Thank you for including Aprilaire as part of your home comfort system.

The description you have given us sounds as though there is a problem with the communication between the 8570 thermostat and the model 58 humidistat. You may want to recheck that all the connections at the ADHC and 8570 are snug, including the sensor to the outdoors. If the connections are snug and the fault reoccurs, you may remove the "A" and "B" wires between them and determine if the fault reappears. If it does not then the problem would probably be a broken wire.

If you have further questions, or need more assistance, feel free to contact us.


Replacement question on my Aprilaire Humidifier

Thursday, September 27, 2012 by Aprilaire Team

Consumer question:

I plan on replacing my (2) 760 Humidifiers with two new 700 humidifiers and would like to receive installation instructions, particularly the wiring. Can you assist - I could not find anything on the site.


Aprilaires' response:

The 700 would be the correct replacement for the 760 humidifier. They are the same size and fit into same opening in the ductwork. The only difference would be how they wire into the humidistat. Also, each humidistat installs differently from each other.

All installation instructions come with the humidifier and humidistat.
Thank you!


How do I get more humidity out of my humidifier?

Friday, August 24, 2012 by Aprilaire Team
Consumer question:
Just installed a 600 unit. We had to turn blower on because furnace time alone was not increaing the RH enough. Will the blower shut off once the desired RH is reached or do I need to flip the switch? My concern is that without the blower the desired RH might not be attained.
Aprilaires' response:
Thank you for contacting us regarding your model 600 humidifier. If the control with your model 600 is the model 60 automatic digital humidistat control (ADHC), you have an optional blower activation built into the control. When wired properly, the model 60 can extend the blower run time to allow your humidifier to continue to run after a heat call has been satisfied. Once the humidity set point has been satisfied, the blower activation will turn off automatically.

If your control does not offer the blower activation or you are not using the available blower activation, the control does not have the capability to turn off the blower when the humidity set point has been reached. In this case the blower would need to be turned off manually.

Additionally you have the option to call our technical support department at 1-800-334-6011 to discuss this with one of our technicians over the phone. Our tech support department is available Monday through Friday, 7 am to 5 pm CST.

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. 1-800-334-6011.


Lots of water running down the drain tube, is that correct?

Thursday, June 28, 2012 by Aprilaire Team
Consumer question:
I had a model 700 Aprilaire humidifier installed yesterday and have a couple of questions;

1) it seems to have a lot of water when running coming out of the drain tube, is that normal?
2) I had to install the hunidifier on the return side becuase there was no room on the feed side of the furnace. I put the thermostat on the return side also but the reading goes way up and then back down when its operating when it kicks on and off. Should I put the thermostat on the feed side so its not on the same side as the humidifier? Its running in manual mode right now, I have to run the sensor outside adn my basemnet is finished so thats going to be a challenge.

Aprilaires' response:
Thank you for choosing the Aprilaire line of humidifiers for your home comfort system.
The amount of water that is discharged down your drain should be approximately 3 gallons per hour. Your description of the extreme humidity swings when the unit is cycling on and off lead me to the conclusion that the humidifier control may be mounted too close to the humidifier, or is mounted between the humidifier and the furnace, allowing for the humidifier output to affect the sensing of the control. It is recommended , in the installation guide that the control should be mounted at least 6" upwind of the humidifier.

If you have other questions regarding your Aprilaire 700 humidifier, please contact us at the number below. We appreciate your business.

My Aprilaire humidifier control is showing an E1 error? Help!

Monday, June 11, 2012 by Aprilaire Team
Consumer question:
I have an 600 model humidifer that has been working fine since installed. I noticed my house was dry this past week and discover an E1 error on the humidstat. I reset the unit a few times but the error keeps coming back.

Aprilaires' response:

Thank you for contacting us.
Unfortunately an e1 error code would indicate an issue with the relative humidity sensor on the back or an issue with the circuit board on the control.
The humidistat would need to be serviced by the point of purchase or another local dealer.
Here is our dealer locator if you need to find a recommended local dealer:


My model 400 Aprilaire humidifier is not running in normal conditions, suggestions?

Wednesday, May 23, 2012 by Aprilaire Team
Consumer question:
Water flows and humidifier on light comes on only in reset mode but humidifier does not come on and activate water flow in normal mode. I have turned dial to max humidity but still does not activate water flow when furnace comes on. I am running in automatic mode with wiring installed per installation manual. I have the outdoor sensor installed but not run outside yet. Please advise. Thank you
Aprilaires' response:

Thank you for your email regarding your model 400 Aprilaire humidifier. If the outdoor sensor is in an area where the temperature is above 60F the humidifier will only run in the test mode. You may confirm this by moving the manual/auto switch to the manual position. This will allow the control to work off the manual sensor on the control rather than the outdoor sensor.


Can I set my Aprilaire model 5000 to come on anytime my furnace or air conditioning is running?

Wednesday, May 16, 2012 by Aprilaire Team

Consumer question:

Can I set my air cleaner to a mode in which it will only be active when the furnace (or air condition) is running? And what is the difference between the Constant Cleaning mode and the Allergies mode - is it that the Allergies mode shuts the air cleaner after 24 hours and then what?

Aprilaires' response:

Thank you for your email regarding your model 5000 Aprilaire Electronic air cleaner.
You can set your model 5000 to be active only when the furnace is running if it is wired correctly. Press the button on your event control that has the arrow on the screen pointing to the event that it is set for. This will turn that arrow off rendering all events inactive.

The difference between Constant and Allergy; Constant Cleaning will run for 24 hrs, 7 days a week until turned off in the same manner discussed earlier. Allergy will run for 24 hrs then shut off the event on it's own. Then it will be set in the mode discussed earlier running only when the furnace runs.


I need humidity in the Summer, what should I do?

Wednesday, April 25, 2012 by Aprilaire Team
Consumer question:
My heating/air cool unit is now controlled by a new thermostat that allows fan circulation about 35% of the time whether the heat or cooling is running or not. Will the humidifier work when the fan is on whether it is on heating or cooling? I live in an area which humidity averages about 12% during the summer. I need to add humidity during those times.
Aprilaires' response:

Thank you for that very good question regarding the Aprilaire humidifier operation.

The answer to your question depends on the type of humidity control that was installed with the humidifier. In the event that the humidity control was the type that used an outdoor temperature sensor to regulate the humidity, then the humidifier would not add humidity in the summer months. this type of control would disable the humidifier when the outdoor temperature would go above 60 degrees. If the humidity control does not use the outdoor temperature sensor, then you may be able to humidify during the summer months. Just be aware that the air conditioning system will remove some humidity during its normal operation; which would take longer to bring the humidity level up.