Aprilaire 400 series User manual

READ AND SAVE THESE INSTRUCTIONS

Owner’s Manual

For Models 400, 550, 600 & 700

Includes Safety & Operating Instructions

and Warranty Information

Automatic Humidifiers

TABLE OF CONTENTS

WARNING 120 volts may cause injury from electrical shock.

Disconnect power and shut off water supply before servicing.

CAUTION Sudden operation may cause personal injury or

property damage. Turn the Aprilaire Humidifier Control to “OFF” or

lowest setting before servicing.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Principle of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Operating Instructions – Model 400, 600 & 700

• Automatic Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

• Manual Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Operating Instructions – Model 550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Effect of Water Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Annual Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Annual Summer Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Periodic Preventative Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

MAINTENANCE INSTRUCTIONS

Model 400 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Model 600 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Model 700 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Model 550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Limited Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Replacement Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

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Genuine Replacement Water Panel®evaporators are available from your

installing contractor or from most other heating and air conditioning

contractors in your area. However, if you still have difficulty in obtaining a

replacement Water Panel evaporator, use the dealer locator in our web

site (www.aprilaire.com) or look in the Yellow Pages under Humidifying

Apparatus or Heating & Air Conditioning Contractors. Purchase only

genuine Aprilaire Water Panels to maintain performance.

Thank you for your recent Aprilaire®Humidifier purchase. We sincerely

appreciate your business and are pleased to add your name to our

growing list of customers. With this purchase, you have invested in the

highest quality equipment currently available. Research Products

Corporation is the largest manufacturer of whole house humidifiers, air

cleaners, and energy recovery ventilators and is a recognized leader in the

heating and air conditioning industry today.

Please be assured that in addition to product quality, we are also committed

to unit performance as well as customer satisfaction. Your unit will require

periodic maintenance to assure you of continued fine performance. Please

proceed as shown on page 9 to obtain service parts and/or replacement

Water Panel®evaporators.

Now, please take a few minutes and read the appropriate section of this

booklet. This will familiarize you with the benefits you will receive from

the equipment you just purchased and help you understand the routine

maintenance that will be required. Be sure to register your Humidifier

with us for our records and your protection. You may do so by registering

online at: www.aprilaire.com/warranty.

INTRODUCTION

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With your purchase of a humidification system, you have invested in a

humidifier that operates on the evaporative principle – nature’s own way

of adding moisture – and will provide the proper relative humidity

throughout the heating season. It is very possible that you have questions

concerning your new humidifier – questions on what it can do for you, and

what you should do to receive maximum benefits from it. This booklet is

intended to help you do exactly that.

Nature, in producing an invigorating comfortable April day, combines just

the right temperature and the right amount of moisture. Aprilaire

Humidifiers employ the same principle, with refinements, to give you the

proper relative humidity for maximum allowable comfort all winter long.

The important considerations in the evaluation of a humidifier are Positive

Control, Sufficient Capacity, Trouble-free Performance and Minimum

Maintenance. The operating principle of your Aprilaire provides all of

these advantages. Here, briefly, is the method:

The Aprilaire Humidifier is installed to operate in conjunction with the

furnace blower motor. When the Aprilaire Humidifier Control calls for

humidity and the blower motor is operating, water flows to the

distribution tray located at the top of the unit. The water is uniformly

distributed across the width of the tray and through a scientifically

designed system of outlets. It flows by gravity over the Water Panel®

evaporator, the heart of the unit. Dry, hot air is moved through the

moisture-laden Water Panel evaporator where the evaporation takes

place. The now humidified air carrying moisture in vapor form

(nature’s own way) is circulated throughout the home.

The correct water flow is determined by an orifice equipped with

each drain type unit. When the unit is operating, there will be a small,

steady stream of water to drain, which flushes away most of the

trouble-causing minerals. Do not use the saddle valve to regulate the

water flow. It is designed to be completely opened or closed. The minerals

and solid residue not trapped by the replaceable Water Panel evaporator are

flushed down the drain in the Models 550, 600 and 700. This is the most

effective and least expensive method to dispose of trouble-causing minerals.

The drain also eliminates the problems caused by stagnant water.

There are some homes where drain facilities are not accessible or

available. For these situations, or where high water hardness is not a

problem, the newest Aprilaire, Model 400, is designed to satisfy these

applications.

I. PRINCIPLE OF OPERATION

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Capacity is high because an average-size home (10,000 cu. ft.) requires

the addition of approximately 9 gallons of water per day to maintain 35%

relative humidity when the outside temperature is 20°. The smallest

Aprilaire Humidifier under most operating conditions, has this humidifying

capacity. Trouble-free performance and minimum maintenance are

assured by the design features of the Aprilaire Humidifier. All unit

housing parts that come in contact with water are non-metal and will

never rust or corrode. Neither heat nor water will affect them under

normal operating conditions.

The Water Panel®evaporator, designed especially for uniform, high

evaporation, along with the Scale Control Insert efficiently traps mineral

deposits which are often the cause of damage to working parts in

ordinary humidifiers. No “white dust” can be distributed throughout the

living quarters. The Water Panel evaporator is the heart of the unit and

must be in good condition to assure high capacity trouble-free

performance. It should be changed once a year with the exception of the

Model 400 where it should be changed twice a heating season.

Older design water distribution trays have a granular coating in the

bottom of the distribution tray to provide equal distribution of water to

each of the openings assuring an even flow over the Water Panel

evaporator. Do not clean the mineral scale off the bottom of the water

distribution tray at the end of the humidification season. If the granular

coating is removed, it is not necessary to purchase a new distribution

tray. You can accomplish the same uniform performance by applying a

small amount of liquid dishwashing detergent over the entire inside

surface of the water distribution tray. This will allow the water to flow

evenly through each of the openings, provided, of course, the unit is level

in order to achieve maximum capacity.

The current distribution tray which incorporates a synthetic fabric liner

that replaces the granular coating, is designed to deliver water uniformly

over the entire top surface of the Water Panel evaporator, provided it is

mounted level. It is normal for some mineral deposits to form in the

distribution tray as it dries out between humidification cycles. These

deposits can actually help distribute water in the tray, but if they form

enough to block the openings, they should be removed as described in the

“Periodic Preventative Maintenance” section of this manual.

There are many humidifiers on the market. They all add moisture… with

varying degrees of efficiency. None, however, can provide the features,

design, and performance incorporated into your Aprilaire Humidifier.

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II. OPERATING INSTRUCTIONS – 400, 600 & 700

There are 2 possible modes of operation of your Aprilaire Humidifier

Control – Automatic and Manual. An explanation of both modes follows:

Automatic Mode: (Manual Mode-see pg 6)

Your Aprilaire Humidifier Control is installed in the cold air return duct.

During the first heating season, your Humidifier Control needs to be set

initially to match your home’s condition. Please follow these steps when

adjusting your control (refer to Figure A).

1. Turn the dial setting knob to “5,” which is within the normal range.

During the next 24-48 hours it may be necessary to adjust the dial for

more or less humidity, depending on your personal comfort and home’s

requirements. Refer to the “Operation Guide” (Table 1).

2. During the coldest portion of the first heating season, minor adjustments

may be necessary. This is dependent upon your home’s construction.

Refer to the “Operation Guide” (Table 1).

TABLE 1 – Operation Guide

Condition Solution

Condensation on windows Reduce the setting on the control dial

by 1 increment.

Lack of humidity Increase the setting on the control dial

by 1 increment.

Humidifier does not operate Turn dial to “Test/Reset.” Make certain

furnace is operating in heat mode.

If unit still doesn’t operate, contact your

heating contractor.

Humidifier won’t shut off Turn dial to “Off.” If unit continues to

operate, contact your heating

contractor.

Test mode System operation is checked by setting

the knob to “Test/Reset.” Make certain

furnace blower is operating and furnace

is calling for heat. Humidifier will

operate for one minute. Be sure to turn

the control knob back to the prior setting

after checking humidifier operation.

Reset Water Panel change Turn the control knob to the

“Test/Reset” position until the “Change

Water Panel” light blinks to reset the

water panel change indicator timer.

(Blower must be operating and furnace

calling for heat.) Be sure to turn the

control knob back to the prior setting

after resetting the timer.

indicator

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Your Aprilaire Automatic Humidifier, is a high precision system that will

accurately maintain the relative humidity in your home. For every 1°

change in outdoor temperature, the control will automatically adjust the

indoor relative humidity (RH) by 1/2%. If you would like to determine the

RH in your home, follow these steps:

1. Determine the outdoor temperature.

2. Activate the furnace blower by setting your thermostat to a higher

temperature.

3. Turn the control dial setting to the “Off” position. Then, slowly turn the dial

clockwise until you hear the solenoid valve on the humidifier “click on.”

Next, slowly turn the dial counter clockwise until you hear the solenoid

valve “click off”. At this point, make note of the dial setting.

4. Locate your dial setting on Table 2. Follow the dial setting to the right

until it intersects with the current outdoor temperature. This is the

relative humidity in your home under existing conditions.

5. Return the thermostat and the Humidifier Control to their original

settings.

The Automatic Humidifier will accurately control the humidity in your

home to a maximum of 45% RH and a minimum of 10% RH. The values of

outdoor temperature and dial settings may fall in between or outside of

the listed values in Table 2. In these cases, you can only approximate your

home’s actual indoor RH.

The relative humidity in your home

will now be accurately controlled to

meet your needs and should not

need further adjustment during

future heating seasons. Make note

of the dial setting in the event you

temporarily move the knob when

performing annual maintenance of

the Aprilaire Humidifier.

AUTOMATIC MODE

FIGURE A

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Manual Mode: (Automatic Mode – see pg 4)

Your Aprilaire Humidifier Control is installed in the cold air return. It is

important to anticipate a drop in outdoor temperature and reduce the setting

accordingly to avoid excessive condensation. For example, with an outdoor

temperature of 20° the correct setting will be 35% relative humidity. If the

temperature is expected to fall to 0° that evening, then merely reduce the

setting to 25% several hours prior to the temperature change.

The recommended settings on the Humidifier Control are based on years

of research and experience (see Table 3). These settings represent a

compromise between RH levels that would be most desirable for comfort

reasons and humidity levels that are suitable for protection of your home

and to avoid condensation on your windows. For example, a wintertime

indoor RH of 50% may be considered ideal, but unfortunately, it probably

would result in damage to your home. Observance of the recommended

RH levels on your Humidifier Control, therefore, is an important safeguard.

Condensation of water on inside windows in the form of fogging or frost

is usually an indication of too much relative humidity. This same

condensation can take place in other areas in your home with the

possibility of damage resulting.

As an example, if the outdoor temperature is 20°F, and, following step 3,

the humidifier turns off at “5” on the dial range, then the RH in your home is 35%.

-10 0 10 20 30 40

110 10 10 15 20 25

210 10 15 20 25 30

310 15 20 25 30 35

415 20 25 30 35 40

520 25 30 35 40 45

625 30 35 40 45 45

730 35 40 45 45 45

Outdoor Temperature (°F)

Dial Setting

TABLE 2 – % Relative Humidity Guide

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Your Aprilaire Humidifier Control

is a precision instrument that can

be used to determine the RH

accurately in your home during

the winter.

To do this, follow these steps:

1. Activate the furnace blower by

setting your thermostat to a

higher temperature.

2. Turn the control dial setting to

the “Off” position. Then, slowly

turn the dial clockwise until you

hear the solenoid valve on the humidifier “click on.” Next, slowly turn the

dial counter clockwise until you hear the solenoid valve “click off.” At this

point, read the RH on the dial. This will be very close to the actual RH

in your home. (See Figure B)

To check the humidifier operation, set the knob to “Test/Reset”, make

sure that the water saddle valve is open and that there is electricity to the

unit. The furnace blower motor must be operating and the furnace calling

for heat for the Aprilaire Humidifier to function. Note: Turning the knob to

“Test/Reset” resets the “Change Water Panel” internal timer. After the

humidifier has operated for one minute and water is entering the unit and

coming out at the drain, reduce the humidistat setting to the

recommended inside relative humidity, depending on the outside

temperature. DO NOT LEAVE IN TEST MODE AS HUMIDIFIER WILL NOT

OPERATE. Follow the suggested settings prior to a drop in the outside

temperature.

MANUAL MODE

FIGURE B

TABLE 3 – Outdoor-Indoor Relative Humidity

Outside Temperature Recommended RH

+40°F 45%

+30°F 40%

+20°F 35%

+10°F 30%

0°F 25%

–10°F 20%

–20°F 15%

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Your humidifier will operate effectively using either hot, cold, hard or

mechanically softened water. Whether to use available tap water, even

though it may be quite hard, or chemically softened water, is a common

concern to homeowners when installing a humidifier.

Water used in homes contains varying amounts of minerals. The residue

remaining as a result of hard water evaporation is primarily calcium and

magnesium components and is usually quite hard, scaly, and dense.

Residue from softened water tends to be soft and fluffy and has a greater

volume than hard water scale. The service life of a Water Panel evaporator may

be extended by using hard water. In either case, the Water Panel evaporator

is usually changed once a year with the exception of the Model 400 which

should be changed twice a heating season. In the drain-equipped models,

most of these solids are effectively controlled by flushing them down the

drain.

Your new Aprilaire Humidifier is controlled by a manual humidistat

installed either in the living area or in the cold air return. It is important to

anticipate a drop in temperature and reduce the setting accordingly to

avoid excessive condensation. For example, with an outside temperature

of 20° the correct setting will be 35% relative humidity. If the

temperature is expected to fall to 0° that evening, then merely reduce the

setting to 25% several hours prior to the temperature change.

Be sure to keep fireplace dampers closed when not in use. They provide

an excellent escape route for heat, as well as humidity.

On occasion, indoor moisture producing activities such as clothes drying,

cooking, showers, etc., may raise the relative humidity level higher than it

should be, even though the Aprilaire Humidifier is not operating. Telltale

indications, again, are condensation or frost on cold surfaces such as

windows, doors, walls, etc. If such condensation persists for several

hours, your home should be ventilated to dissipate the potential damaging

excess moisture levels.

III. OPERATING INSTRUCTIONS – 550

V. EFFECT OF WATER CHARACTERISTICS

IV. ADDITIONAL INFORMATION FOR ALL MODELS

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VI. ANNUAL MAINTENANCE

VII. ANNUAL SUMMER SHUTDOWN

For best performance, we recommend that you replace the Water Panel

evaporator in your Aprilaire Humidifier annually with the exception of

Model 400 which should be changed twice a season. If you have a

Humidifier Control equipped with a water panel timer, the “Change Water Panel”

light will be lit (during operation only) when it is time to change your Water Panel.

To purchase a new Water Panel:

• Call the installer of your Aprilaire Humidifier. This information is often

found on your equipment.

• Call your heating and air conditioning dealer.

• Use our “Dealer Locator” at: www.aprilaire.com

• Look in the Yellow Pages under Humidifying Apparatus or

Heating & Air Conditioner Contractors.

• If none of the above is successful and you still need information, please

feel free to write us.

• Purchase only Genuine Aprilaire Water Panels to maintain performance.

If your humidifier is equipped with an automatic control, after replacing the Water

Panel, turn the control knob to the “Test/Reset” position until the “Change Water

Panel” light blinks to reset the Water Panel change indicator timer. (Blower must

be operating and furnace calling for heat.) Be sure to turn the control knob back to

the prior setting after resetting the timer.

1. For Models 400, 550, and 600 close the bypass damper, which is a part

of the unit, with the use of the small damper handle. For older Model

550s without a built in damper, closer the bypass which is installed in

the bypass pipe.

2. Shut off the water supply to the humidifier by closing the saddle valve.

Humidifier Control:

There is no adjustment to the Humidifier Control required for summer

shutdown. (Applies to both Automatic and Manual Mode.)

Service hot water, 140° maximum, is recommended with drain type units for

increasing capacity and for heat pump applications.

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1. Disconnect electrical power

to the furnace and shut off

water supply.

2. Disconnect the water line at

the inlet compression nut.

3. Remove the in-line strainer

from inside the inlet side of

the valve by using a small

nail or wire.

4. Flush the in-line strainer

clean or replace with a new

strainer, Service Department,

Part No. 4004.

5. Replace the in-line strainer

and reconnect the inlet water

line. (Double Wrench To

Prevent Leaking.)

6. Disconnect the water line at the outlet compression nut.

7. Remove the orifice from the copper or plastic tube and make sure

this small opening is unplugged.

8. Replace the orifice and reconnect the outlet water line.

(Double Wrench To Prevent Leaking.)

9. Turn on water supply and reconnect electrical power to

the furnace.

OUTLET

COMPRESSION

NUT

ORIFICE

INLET

COMPRESSION

NUT

SOLENOID

VALVE

IN-LINE

STRAINER

INSPECTION AND SERVICE INSTRUCTIONS

NOTE: Periodic inspection and preventative maintenance of your total

heating system is important for efficient and safe operation. Your heating

contractor should include humidifier service at the same time.

All models are equipped with an in-line water strainer and orifice as

shown below. These parts should be inspected and cleaned periodically to

assure continued proper unit performance.

VIII. PERIODIC PREVENTATIVE MAINTENANCE

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1. Front Cover

2. Feed Tube

3. Integral Bypass Damper

4. Water Panel Evaporator

Assembly

5. Distribution Tray

6. “V” Notches

7. Water Panel

8. Scale Control Insert/Float

Chamber

9. Overflow Hose

10. Float Cover

11. Float

12. Water Level Sensor Assembly

1. Note Humidifier Control setting and turn dial to the “Off” position.

2. Turn off water supply. Turn 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.

4. Carefully pull the plastic feed tube (2) out of the distribution tray (5) at the top of the Water

Panel evaporator assembly (4). Tip the Water Panel evaporator assembly forward and lift it

out of the humidifier. Do not tip the Water Panel evaporator assembly more than needed to

clear the housing to avoid over-bending the water level sensor assembly (12).

5. Unsnap the distribution tray (5) 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 used water panel (7) out of the scale control insert/float chamber and dispose of

the water panel. Inspect the overflow hose (9) to make sure it is open.

7. Remove the float cover (10) and inspect the floats (11) and float chamber for mineral build-

up. Remove deposits as needed from floats, float chamber and scale control insert. Wash

the parts with a disinfecting cleaner. Reassemble the floats and float cover. Make sure

stems of both floats extend through openings in float cover and that floats move freely up

and down.

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

9. Slide a new Aprilaire No. 45 water panel into the scale control insert/float chamber. Snap

the distribution tray back on the scale control insert.

10. Re-install the Water Panel evaporator assembly into the humidifier. Take care not to over-

bend the water level sensor assembly. Push the top of the Water Panel evaporator

assembly firmly back until it snaps into place.

11. Push the end of the feed tube back firmly into the distribution tray. Replace the front cover.

12. Turn on the water supply. Return integral bypass damper to appropriate position.

13. Check system operation:

Humidifier Control: (Automatic or Manual) Check system operation and reset change water

panel indicator by setting the knob to “Test/Reset”. With furnace blower operating and

furnace calling for heat, humidifier will operate for one minute. DO NOT LEAVE IN TEST

MODE AS HUMIDIFIER WILL NOT OPERATE.

14. Reset Humidifier Control to its original position. Check operation.

MAINTENANCE INSTRUCTIONS FOR

APRILAIRE HUMIDIFIER MODEL 400

CAUTION! Sudden operation may cause personal injury or

property damage. Turn Humidifier Control to “off” or

lowest setting before servicing.

MODEL 400

MODEL

400

- 12 -

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

2. Turn off water supply. Turn 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. Carefully 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.