Aprilaire 400 instruction

MODEL 550

MAINTENANCE INSTRUCTIONS FOR APRILAIRE HUMIDIFIER MODEL 550

CAUTION! Sudden operation may cause personal injury or property damage. Turn Humidistat to “off” or lowest setting before servicing.

	3	5	6	4
			6	4
1	10			8

2	9

1. Note Humidistat setting and turn dial to the “OFF” position.

1.Front Cover

2.Feed Tube

3.Nozzle

4.Water Panel Evaporator Assembly

5.Distribution Tray

6.”V” Notches

7.Water Panel

8.Scale Control Insert

9.Drain Hose

10.Integral Bypass Damper

2.Turn offf water supply. Turn the integral bypass damper (10) to the SUMMER position.

3.At the side of the unit opposite the airflow duct pull front cover (1) off holding with both hands and set aside.

4.Carefully pull the plastic feed tube (2) out of the nozzle (3) 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 from the scale control insert (8). Follow the instructions below depending upon the type of distribution tray in your 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. See page 3 if removed.

6.Slide the Water Panel evaporator (7) out from the Scale Control Insert (8). Clean the insert frame by twisting and flexing it to loosen the calcium deposits. Replace the Water Panel evaporator (Stock No. 10) and with a new Genuine Aprilaire Water Panel. Slide the pad back into the insert frame with color mark up and snap the distributor tray back into place.

7.Check the condition of the feed tube and replace if tube is damaged or brittle.

8.Re-install the Water Panel evaporator assembly into the unit by fitting its drain into the round receptacle at the base of the unit. Push the assembly in at the top against the beveled tabs that will hold it in place. Push the end of the feed tube back firmly into the nozzle and replace the front cover.

9.Remove the drain hose (9) from the bottom of the unit and bend and flex it to loosen the internal calcium deposits. Then flush it with water under pressure and slip it back onto the drain fitting.

10.Turn on the water supply.

11.Check system operation:

Humidistat: With the furnace blower operating and the furnace calling for heat, turn up Humidistat and check system operation .

12.Set Humidistat to its original position.

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