2
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
STS (steam-to-steam) humidifi ers use pressurized boiler steam to heat clean fi ll
water into chemical-free steam for humidifi cation. See Figure 3-1.
STS humidifi ers are designed for use with tap/softened water and are
available with an option for RO/DI water (water that has been treated using
reverse osmosis, or deionized water).
TAP/SOFTENED WATER
A conductivity probe (Figure 3-2) monitors the water level in the tap/softened
water STS humidifi er; therefore, water conductivity must be at least 30 μS/
cm for proper operation. A tap/softened water STS humidifi er will not operate
with RO/DI water. For RO/DI water, use STS with the RO/DI water option.
RO/DI WATER OPTION
STS humidifi ers with the RO/DI water option control water level with a fl oat
valve (Figure 3-3). Float valves are compatible with RO/DI water only.
Humidifi ers with the RO/DI water option are virtually maintenance free and
require little or no downtime.
WATER TYPE CONVERSION
STS tap/softened water humidifi ers can be converted in the fi eld for use with
RO/DI water, and STS RO/DI water humidifi ers can be converted in the fi eld
for use with tap/softened water. Contact your DriSteem representative or
distributor for parts and instructions.
Product overview
OVERVIEW
mc_071912_1545
Supply water guidelines
Supply water quality is an important component
of humidifi er reliability and maintenance.
Examples:
• Corrosive water can decrease the service
life of the humidifier.
• Excessive water hardness can increase the
humidifier maintenance requirements.
To maximize humidifi er service life and
minimize humidifi er maintenance, DriSteem
has established guidelines for supply water
See Table 2-1.
Table 2-1:
DriSteem supply water guidelines
Chlorides*
RO or DI water
Softened water
Tap water
* Damage caused by
chloride corrosion is
not covered by your
DriSteem warranty.
< 5 ppm
< 25 ppm
< 50 ppm
Total hardness
Tap water
< 500 ppm
pH
RO, DI, or softened water
Tap water
7 to 8
6.5 to 8.5
Silica
< 15 ppm
You may wish to take action to mitigate
potential negative effects to your
humidifi er. Supply water outside of these
guidelines may void your DriSteem
warranty. Please contact your DriSteem
Representative or DriSteem Technical
Support if you need advice.
