Principles Of Operation; Specifications & Dimensions - Aprilaire 800 Installation & Maintenance Instructions Manual

PRInCIPleS of oPeRaTIon

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 .
SPeCIfICaTIonS & DIMenSIonS
Table 1 – Specifications
Voltage kw
120V
208V
240V
Maximum
steam capacity
gal/day
1 .4 11 .5
2 .4 20 .5
2 .8 23 .3
fIGURe 1 – fill and Drain System and Canister
Fill Cup
Overflow
Flow Control
Orifice
Fill
Inlet
Fill Valve
Supply
Water
nominal Current draw
(amps)
amps
11 .5
11 .5
11 .5
Steam
Outlet
High Water
Level Sensor
Electrodes
Canister
Drain Valve
Drain Cup
Drain
90-1522
Humidifier unit
operating weight
lbs
23
23
23
3