Aprilaire 800 - Manual (Page 3)

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The Aprilaire ® Model 800 Canister Steam Humidifier delivers humidity in the
form of steam to the conditioned space via the HVAC system duct or optional
Aprilaire Model 850 Fan Pack. The humidifier generates steam by energizing
two electrodes that extend into a canister of water. Current flowing between
the electrodes causes the water to boil, creating steam. Water is introduced
to the humidifier through a fill valve to a fill cup located in the top of the
cabinet. The fill cup serves as an overflow reservoir and provides an air gap
between the humidifier and water source. The steam canister is filled from
the bottom. The canister is seated in a drain cup assembly which includes a
drain valve. The drain and fill valves work together to maintain water level
in the canister to deliver the rated steam capacity based on the electrical
conductivity of the water and to temper drain water. See
Figure 1 for
representation of fill and drain system and canister .
Steam is delivered into the airstream through a dispersion tube mounted
in the HVAC system ductwork. Openings in the dispersion tube are fitted
with “tubelets” which extend into the center of the tube. The design of the
dispersion tube and tubelets distribute steam over a wide area in the duct
and direct any condensed moisture back into the steam hose.
pRINCIpLES OF OpERATION
FIGURE 1 – Fill and Drain System and Canister
90-1522
Steam
Outlet
Drain
Supply
Water
Drain Cup
Drain Valve
Canister
Electrodes
High Water
Level Sensor
Flow Control
Orifice
Inlet
Fill Valve
Overflow
Fill
Fill Cup
Thank you for your recent Aprilaire ® humidifier purchase. We appreciate
your business and are pleased to add your name to our growing list of
customers. You have invested in the highest quality equipment available.
Aprilaire manufactures whole-house indoor air quality products and is a
recognized leader in the heating and air conditioning industry.
Your humidifier will require periodic maintenance to assure continued
consistent performance . See page 14 .
Now, please take a few minutes and read 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 warranty online at:
www.aprilaire.com/warranty .
INTRODUCTION
Genuine Aprilaire Replacement Model 80 Steam Canisters are
available from your installing contractor or from most other heating
and air conditioning contractors in your area. Use the dealer locator on
our web site (www.aprilaire.com) or look in the yellow pages under
Humidifying Apparatus or Heating & Air Conditioning Contractors.
SEQUENCE OF OpERATION
When the Automatic Digital Humidifier Control (ADHC) detects humidity
below the set point, and provided the humidifier is turned on and the
HVAC system blower is operating, the internal controller in the humidifier
energizes the electrodes and measures the current flowing through the
water between them. The controller adjusts water level in the canister via
a fill valve and a drain valve to maintain a constant current. The operating
water level in the canister depends on the mineral content of the water
which determines conductivity.
The ADHC has the ability to turn on the HVAC system blower if the
homeowner or installer chooses to utilize that feature. See ADHC
installation manual .