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Maintenance Instructions for Aprilaire Models 600, 600A & 600M


Maintenance Instructions for Aprilaire Models 600, 600A & 600M


1.        Note Humidifier Control setting and turn dial to the "OFF" position.

2.        Turn off water supply. Move the integral bypass damper (3) to the SUMMER position.

3.        Press the tabs in the latches on the top and bottom of front cover (1) and pull cover off base with both hands. Set aside.

4.        Pull the plastic feed tube (2) out of the distribution tray (5) at the top of the Water Panel evaporator assembly (4). Pull this assembly out by grasping at top and tipping out.

5.        Unsnap the distribution tray (5) from the scale control insert (8). Follow the instructions below depending upon the type of distribution tray in you humidifier.

For trays with a synthetic fabric liner: Lightly scrape out or brush off any mineral deposits, being careful not to stretch or loosen the synthetic fabric liner. Soaking the tray in vinegar or a lime-removing agent is helpful when trying to remove stubborn mineral deposits.

For trays with granular coating: Do not scrape off the granular coating, but lightly scrape out any mineral deposits and clean the "V" notches (6). This textured surface helps ensure even water flow for maximum performance. If the granular coating has been removed, place several drops of liquid dishwashing soap on the distribution tray. This will only need to be done once if there is no granular coating.

6.        Slide the Water Panel evaporator (7) out of the scale control insert (8). Clean the scale control insert of mineral deposits. Slide the new Water Panel evaporator into the scale control insert with the colored spot up and snap the distribution tray (5) back into place.

7.        Inspect the plastic feed tube (2) by gently flexing it and looking for cracks or signs of water. Replace tube if it is cracked, brittle, or has been damaged.

8.        Reinstall the Water Panel evaporator assembly (4) into the humidifier by fitting its drain into the round receptacle at the base of the humidifier. Push the assembly in at the top until it snaps into place. Push the end of the feed tube (2) firmly back into the distribution tray (5) and replace the front cover (1).

9.        Remove the drain line (9) from the bottom of the humidifier. If applicable, flex it to loosen any mineral deposit or blockages. Then flush it with water under pressure. If it does not properly clear, replace it. Slip drain line back on the drain fitting. Make sure the drain line has a constant downward slope and is not flattened or blocked.

10.    Turn on the water supply. Return integral bypass damper (3) to appropriate position.

11.    Check system operation:

Automatic Humidifier Control: (Automatic or Manual mode) Check system operation by turning the knob to "Test". With furnace blower operating, humidifier will operate for one minute. DO NOT LEAVE IN TEST MODE AS HUMIDIFIER WILL NOT OPERATE. For Controls with Change Water Panel indicator light, turning knob to "Test/Reset" will reset Change Water Panel indicator.

12.    Set Humidifier Control to its original position.