Minerals that are naturally found in water cause the water to
be electrically conductive . Water conductivity is measured in
micro Siemens per centimeter (uS/cm) . Mineral content, also
described as “water hardness” is usually measured in grains per gallon . Because of the variety of minerals that are found in water, there is no
direct correlation between water hardness and conductivity, but generally the higher the mineral content, the higher the conductivity .
The Canister Steam Humidifier is designed to operate on water with conductivity between 125 and 1,250 uS/cm . This correlates loosely with
water with hardness between 3 and 36 grains/gallon . Water that is considered “hard” and also softened water work well in the humidifier . The
humidifier will make steam when plumbed to low-conductivity water but it takes longer to reach nominal capacity .
with low conductivity water, it may take the humidifier one week or more of operation to reach rated capacity, especially if it
is wired to operate on 120 volts. when operating on 240 volts, the humidifier usually will reach nominal capacity within a few
hours, even with lower conductivity water.
As water in the canister boils and turns into steam, minerals are left behind . The remaining minerals, if they remain in solution in the water,
increase the conductivity of the water . Minerals also deposit onto the submerged portions of the electrodes rendering those areas ineffective . As
this occurs, the level of water in the canister rises to expose uncoated electrode surface .
SPeCIfICaTIonS & DIMenSIonS
Table 1 – Specifications
Voltage
kw
Maximum steam capacity
nominal Current draw (amps)
Humidifier unit operating weight
gal/day
amps
lbs
120V
1 .4
11 .5
11 .5
23
208V
2 .4
20 .5
11 .5
23
240V
2 .8
23 .3
11 .5
23
The Canister Steam Humidifier delivers humidity in the form
of steam to the conditioned space via the HVAC system
duct or optional 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
waTeR QUalITy
3
