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?
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.