Aprilaire 400MK Bypass Humidifier Manual Control

$298.00 CAD

  • Manufacturer: Research Products Corp.
  • Brand Name:   Aprilaire 
  • Model:   400MK  (replaces the Aprilaire 445)
  • Category: Water / Large ByPass / Flow Through / Drainless
  • Rated Capacity:  17 gallons / day
  • Supply Voltage Required: 24VAC
  • Manufacturers’ Order Number:  400MK
  • Included Humidifier Control Type: Mechanical
  • Plenum Opening Required: W= 10″  H= 12.75″
  • Water Efficiency Level: 100%

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Aprilaire – Whole House Water-Saving Bypass Humidifier with Manual Humidifier Control 400MK

Model: 400MK


Aprilaire Whole-House Bypass Humidifier for Canada that Features A Built-In Bypass Damper, Manual Control And Utilizes New Evaporative Technology To Minimize Water Use.

This water-saving bypass humidifier is a whole-home solution that helps you achieve total comfort though humidity control. Featuring a drain-free operation that eliminates standing water, the model 400MK is a perfect choice for homes with septic systems, locations where a floor drain is not available, and locations where water conservation is a concern.


  • Minimal water usage
  • No drain required
  • No standing water
  • Provides vital service, temperature and relative indicators
  • Humidifies tightly constructed homes up to 2,500 square foot in size
  • Has an evaporation capacity of 17 gallons per day


Use & Care Instructions – English

Installation Instructions – English

Wiring Diagrams – English

Specification Sheet – English

Installation Instructions 2 – English

Consumer Literature – English




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