Indicates a hazardous situation that could result in death or
serious injury if instructions are not followed.
mc_051508_1145
WARNING
Attention installer
Read this manual before installing, and leave this manual with product owner. This product must be installed by qualifi ed
HVAC and electrical contractors and in compliance with local, state, federal, and governing codes. Improper installation
can cause property damage, severe personal injury, or death as a result of electric shock, burns, or fi re.
DriSteem
Read all warnings and instructions
Read this manual before performing service or maintenance procedures on any part of the system. Failure to follow all
warnings and instructions could produce the hazardous situations described, resulting in property damage, personal injury,
or death.
Failure to follow the instructions in this manual can cause moisture to accumulate, which can cause bacteria and mold
growth or dripping water into building spaces. Dripping water can cause property damage; bacteria and mold growth can
cause illness.
mc_011909_1215
®
technical support: 800-328-4447
CAUTION
Indicates a hazardous situation that could result in damage to or
destruction of property if instructions are not followed.
Hot surfaces and hot water
This steam humidifi cation system has extremely hot surfaces. Water in tank, steam pipes, and dispersion assemblies can
be as hot as 212 °F (100 °C). Discharged steam is not visible. Contact with hot surfaces, discharged hot water, or air
into which steam has been discharged can cause severe personal injury. To avoid severe burns, follow the cool-down
procedure in this manual before performing service or maintenance procedures on any part of the system.
mc_011909_1130
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
ii
Page 3
Warnings and cautions
WARNING
Disconnect electrical power
Disconnect electrical power before installing supply wiring or performing service or maintenance procedures on any
part of the humidifi cation system. Failure to disconnect electrical power could result in fi re, electrical shock, and other
hazardous conditions. These hazardous conditions could cause property damage, personal injury, or death.
Contact with energized circuits can cause property damage, severe personal injury, or death as a result of electrical shock
or fi re. Do not open control cabinet door or remove subpanel access panels until electrical power is disconnected.
Follow the shutdown procedure below before performing service or maintenance procedures on any part of the system.
Shutdown procedure
To prevent serious injury, follow this shutdown procedure before performing service or maintenance procedures on this
humidifi er, after the tank has cooled down and drained.
1. Follow the “Cool down humidifi er” instructions on Page 50 (tap/softened water STS) or Page 53
(STS with RO/DI water option) to put the humidifi er at a safe temperature for service.
2. Use the Vapor-logic
3. Place all power disconnects in OFF position and lock in OFF position.
4. Close the fi eld-installed manual water supply shut-off valve.
5. Close the manual shut-off valve on the inlet steam supply.
®
keypad/display to change control mode to Standby.
CAUTION
Hot discharge water
Discharge water can be as hot as 212 °F (100 °C) and can damage the drain plumbing.
Humidifi ers equipped with a water tempering device need fresh make-up water in order to function properly. Make sure the water
supply to the water tempering device remains open during draining.
If the humidifi er is not equipped with a water tempering device, allow the tank to cool before opening the drain valve.
Excessive supply water pressure
Supply water pressure greater than 80 psi (550 kPa) can cause the humidifi er to overfl ow.
mc_123010_1520
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
1
Page 6
OVERVIEW
Product overview
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.
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.
mc_071912_1545
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.
Total hardness
Tap water< 500 ppm
< 5 ppm
< 25 ppm
< 50 ppm
pH
RO, DI, or softened water
Tap water
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.
7 to 8
6.5 to 8.5
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
2
Page 7
OVERVIEW
Product overview
FIGURE 3-1: STS HUMIDIFIERSFIGURE 3-2: WATER LEVEL CONTROL
Notes:
• Drain piping material must be suitable for 212 °F (100 °C) water.
• See the piping drawings on Pages 22 through 25.
FOR TAP/SOFTENED WATER HUMIDIFIER
Tap/softened water STS humidifi er
Humidifi cation steam outlet
Probe water level control
Automatic steam valve
Boiler steam
Steam trap
Condensate return
Water seal
Air gap
Open drain
STS humidifi er with the RO/DI water option
Humidifi cation steam outlet
Float valve water level control
OM-938
Heat exchanger
Manual drain or optional
motorized drain valve
VLC-OM-030
Fill valve closes when
water level rises to this
probe.
Fill valve opens when
water level is below this
probe.
Low-water cutoff.
Pressurized steam to
heat exchanger is cut if
water level drops below
this probe (if steam to
STS heat exchanger
is controlled by
Vapor-logic).
Humidifi ers using tap or softened water control
water levels electronically using a three-rod
probe. The controller responds with the above
actions when the water level reaches each rod.
mc_030910_1335-STS
FIGURE 3-3: WATER LEVEL CONTROL
FOR RO/DI-WATER OPTION HUMIDIFIER
Fill valve
Automatic steam valve
Boiler steam
Steam trap
Condensate return
Water seal
Heat exchanger
Manual drain valve
Air gap
Open drain
OM-939
VLC-OM-026
Humidifi ers using RO/DI water control water
level using a fl oat valve. An optional low-water
cutoff switch is available as a remote water
indicator.
mc_030910_1336-STS
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Float rod
Float ball
3
Page 8
OVERVIEW
Dimensions
FIGURE 4-1: DIMENSIONS, STS MODELS 25, 50, 100, 200, AND 400 (WITH COPPER OR STAINLESS STEEL HEAT EXCHANGERS)
FIGURE 4-2: DIMENSIONS, STS MODEL 800 (WITH COPPER OR STAINLESS STEEL HEAT EXCHANGERS)
Front view
J
K
F
G
D
E
OM-931
Side view
L
Mounting hole:
1/2" dia.
(12 mm) slot
A
H
C
C
OM-932
M
B
Notes:
• Tap/softened water model shown
• See dimensions in Tables 5-1 and 5-2
OM-936
mc_010511_1013-tap
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
4
Page 9
OVERVIEW
Dimensions
Table 5-1:
Dimensions, STS with copper heat exchangers
See drawings in Figures 4-1 and 4-2
Description
A Height**19.5049519.5049519.5049519.5049529.75756
B Width14.7537514.7537519.2548930.2576830.25768
C Length23.6560039.65100739.65100755.15140155.151401
D Bottom to supply inlet of fi rst heat exchanger6.631686.631686.631686.631686.63168
E Bottom to return outlet of fi rst heat exchanger3.63923.63923.63923.63923.6392
F Bottom to supply inlet of second heat exchanger————————14.28363
G Bottom to return outlet of second heat exchanger————————11.24285
H Side to heat exchanger3.25833.25833.25833.25833.2583
J Pressurized steam supply inlet
K Pressurized condensate return outlet
L Side to steam outlet6.251598.632199.6324513.0033013.00330
M Front to steam outlet2.50642.25572.75703.75953.7595
* C, S, and SNC in model numbers are explained in Table 6-1.
** Add 23.5" (597 mm) to overall height when STS is mounted on four support legs. Add 22.5" (572 mm) to overall height when STS is mounted
on two H-legs.
25C50C100C400C800C
inchesmminchesmminchesmminchesmminchesmm
3/4" pipe
thread
3/4" pipe
thread
DN20
DN20
1¼" pipe
thread
3/4" pipe
thread
DN32
DN20
STS model*
1¼" pipe
thread
1¼" pipe
thread
DN32
DN32
1½" pipe
thread
1¼" pipe
thread
DN40
DN32
1½" pipe
thread
1¼" pipe
thread
DN40
DN32
Table 5-2:
Dimensions, STS with stainless steel heat exchangers
See drawings in Figures 4-1 and
A Height**19.5049519.5049519.5049519.5049519.5049529.75756
B Width14.7537514.7537519.2548930.2576830.2576830.25768
C Length23.6560039.65100739.65100755.15140155.15140155.151401
Bottom to supply inlet of fi rst heat
D
exchanger
Bottom to return outlet of fi rst heat
E
exchanger
Bottom to supply inlet of second
F
heat exchanger
Bottom to return outlet of second
G
heat exchanger
H Side to heat exchanger3.25833.25833.25833.25833.25833.2583
J Pressurized steam supply inlet
K Pressurized condensate return outlet
L Side to steam outlet6.251598.632199.6324513.0033013.0033013.00330
M Front to steam outlet2.50642.25572.75703.75953.75953.7595
* C, S, and SNC in model numbers are explained in Table 6-1.
** Add 23.5" (597 mm) to overall height when STS is mounted on four support legs. Add 22.5" (572 mm) to overall height when STS is mounted
on two H-legs.
Description
4-2
25S50S100S200S400SNC800SNC
inchesmminchesmminchesmminchesmminchesmminchesmm
6.851746.851746.851746.851746.851746.85174
3.35853.35853.35853.35853.35853.3585
——————————14.5368
——————————11.0279
3/4" pipe
thread
3/4" pipe
thread
DN20
DN20
1" pipe
thread
3/4" pipe
thread
DN25
DN20
1" pipe
thread
3/4" pipe
thread
STS model*
DN25
DN20
1½" pipe
thread
3/4" pipe
thread
DN40
DN20
1½" pipe
thread
3/4" pipe
thread
DN40
DN20
1½" pipe
thread
3/4" pipe
thread
DN40
DN20
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
5
Page 10
OVERVIEW
Capacities, electrical specifi cations, and weights
Table 6-1:
STS humidifier models and capacities with copper heat exchangers
Steam pressure at connection to STS steam valve (valve provided by DriSteem)
STS models
25C20970321004512054
50C50231506820091240109
100C10045300136400181480218
400C300136580263720327790358
800C650295127557815006801600726
mc_010411_1645
Table 6-2:
STS humidifier models and capacities with stainless steel heat exchangers
• Avoid locations above critical equipment or processes to avoid damage to
the equipment below in the event of a water leak.
• Avoid locations close to sources of electromagnetic emissions such as
power distribution transformers and high horsepower motors controlled by
variable frequency drives.
FIGURE 7-1: RECOMMENDED CLEARANCES
* Minimum access clearance of 18" (457 mm) recommended for periodic removal of top cover
for access to tank.
Left side:
36" (914 mm) with mounted control cabinet.
6"(152) without mounted control cabinet
Tap/softened water
model shown
Front: 36" (914 mm)
Top: 18" (457 mm)*
Right
side:
6" (152 mm)
Bottom:
24" (610 mm)
Rear: 6" (152 mm)
DC-1452
mc_010511_1742-tap
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
7
Page 12
INSTALLATION
Mounting methods
FIGURE 8-1: SUPPORT LEGS, STS MODELS 25, 50, AND 100 ONLYFIGURE 8-2: TRAPEZE HANGER, STS
MODELS 25, 50, AND 100 ONLY
See Note 1
Provide 18"
(457 mm)
See Note 2
minimum
clearance
See Note 3
above cover
See Note 4
mc_010511_1740-tap
OM-933
Tap/softened water model shown
Optional set of four legs and hardware
FIGURE 8-3: WALL BRACKETS, STS MODELS 25, 50, AND 100 ONLY
mc_010511_1741-tap
DC-1454
A
Tap/softened water model shown
STS model
AB
in.mmin.mm
25 and 5015.539424610
B
DriSteem optional wall
1002153330762
brackets (two required)
FIGURE 8-4: H-LEGS, STS MODELS 200, 400, AND 800 ONLY
Tap/softened water model shown
Due to size and weight, STS models
200, 400, and 800 must be mounted
on H-legs.
1¼" (DN32)
minimum
See Note 5
25%
larger than
humidifi er
Tap/softened water model shown
Notes:
1. Secure rods to overhead construction.
2. 3/8" (M10) threaded rod of length required.
3. Angle or channel sized to properly support
humidifi er.
4. Humidifi er drain to appropriate building
waste. Do not drain humidifi er directly into
drip pan. Install water seal as shown on
Pages 22 through 25.
5. Drip pan (by installer) recommended in
overhead installations to prevent possible
water damage to equipment below.
DC-1453
mc_010511_1743-tap
mc_010511_1744-tap
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
8
OM-947
Page 13
Mounting the humidifi er
INSTALLATION
The STS humidifi er tank must be level from side to side and front to back. For
all mounting methods, shim and adjust when mounting, and verify that tank is
level after it is fi lled and at operating weight.
SUPPORT LEGS
See Figure 8-1. Use the enclosed bolts, nuts, and washers to fasten the
legs to the tank.
WALL BRACKETS
See Figure 8-3. DriSteem does not recommend mounting STS model 200,
400, or 800 with wall brackets. DriSteem recommends using 3/8" (M10)
fasteners.
• Concrete or block wall: Use concrete anchors (expansion bolts) rated for the
operating weight of the STS humidifi er. Position the wall brackets so they
are fl ush with the front and back fl anges of the tank.
• Wood stud wall: Mount two horizontal 2 × 4 boards
(100 mm × 50 mm timbers) 16" (404 mm) on center:
– STS 25: Lag bolt (coach screw) the 2 × 4s to two studs.
– STS 50: Lag bolt the 2 x 4s to three studs.
– STS 100: Lag bolt the 2 x 4s to four studs.
Lag bolt the wall brackets to the horizontal 2 × 4s. Position the wall brackets
fl ush with front and back fl anges of tank.
Important:
Installation must comply with local governing
codes.
These mounting methods are the only options
available to maintain compliance to the UL
998 standard. Alternate mounting methods will
compromise the humidifi er’s CE, ETL, and C-ETL
approval.
Support legs, trapeze hanger, and wall
brackets are not available for STS models 200,
400, and 800.
Table 9-1:
STS mounting options
Mounting
method
Trapeze hangerstandard—
H-legs—standard
Support legsoptional—
Wall bracketsoptional—
25, 50, 100 200, 400, 800
STS model
• Metal stud wall: Follow the wood stud wall guidelines above, but provide
a second set of 2 × 4s (100 mm × 50 mm timbers) on the backside of the
wall. Run bolts with washers through the face 2 × 4, through each metal
stud, and through the backside 2 × 4. Fasten the bolts and the face and
backside 2 x 4s to the wall with washers and nuts.
H-LEGS
See Figure 8-4. With the STS tank securely held in place above the fl oor,
attach front and rear supports using the supplied 3/8" (M10) bolts, nuts, and
washers. Make sure the bottom of the tank is supported by the H -leg supports;
this can be accomplished by having the bolts slightly loose as the unit is
lowered to the fl oor, then tighten them after the unit is place.
TRAPEZE HANGER
See Figure 8-2. Secure the threaded rods to an overhead structure strong
enough to support the operating weight of the humidifi er, fi eld-installed piping,
and (if mounted on the humidifi er) control cabinet.
For overhead installations, install a drip pan to prevent possible damage to
equipment below in the event of a water leak.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
9
Page 14
INSTALLATION
Weather cover
FIGURE 10-1: WEATHER COVER EXPLODED VIEW
Panel
Panel
Hinged door
FIGURE 10-2: WEATHER COVER DIMENSIONS
C
Panel
Panel
OM-7466
mc_012511_1606
Hinged door
B
Table 10-1:
Weather cover weights
Weather cover sizelbskg
STS 25 to 100425193
STS 200 to 800550250
mc_012511_1600
A
OM-7465
mc_012511_1607
Table 10-2:
Weather cover dimensions
LetterDescription
AHeight621575661676
BLength43.51105531346
CWidth62157578.251988
DDistance from bottom2255922559
mc_012511_1605
STS 25 to 100STS 200 to 800
inchesmminchesmm
D
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
10
Page 15
Weather cover
The optional STS weather cover is water-resistant and designed to protect an
STS humidifi er from rain and sun. This weather cover has been tested and
approved by ETL Testing Laboratories, Inc., and is listed to UL Standard 1995
and certifi ed to CAN/CSA Standard C22.2 No. 236.
The weather cover is fully assembled at the DriSteem factory.
INSTALLATION NOTES
Open the hinged doors to make necessary connections to the humidifi er. Refer
to the installation section of this manual for all elec tri cal, supply water, and
drain con nec tion requirements.
INSTALLATION ISSUES SPECIFIC TO WEATHER COVER APPLICATIONS
• Installation must comply with all governing codes.
• The bottom of the weather cover is open to ac com mo date piping and
electrical con nec tions.
INSTALLATION
• Electrical connections must be made with approved, outdoor-rated,
watertight conduit.
• Freeze protection must be provided on all water piping.
• Steam supply must be insulated.
• Avoid using steam hose in outdoor applications — the effects of ultraviolet
rays will prematurely age the steam hose.
• Installer must drill a hole in weather cover for steam piping. Seal after
making steam connection to maintain weather protection.
• The steam outlet must be isolated with a union to allow easy disconnection
of the steam supply. This allows easy removal of the weather cover to
access the STS for service and maintenance.
ANNUAL WEATHER COVER MAINTENANCE REQUIREMENTS
• Check all fasteners and verify they are secure.
• Check for any sign of leakage — trace back to origin and repair.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
11
Page 16
INSTALLATION
Outdoor Enclosure
FIGURE 12-1: OUTDOOR ENCLOSURE WITH STANDARD OR OPTIONAL STEAM OUTLET, ELEVATION VIEW
Standard steam outlet
Ventilation fans
STS humidifi er
Power block
See Note 2
Knockouts, 4" (102 mm) on center
Enclosure drain 1½" pipe thread
(DN40) with male nipple
L
Notes:
1. The Outdoor Enclosure has two available steam dis tri bu tion confi gurations. The standard con fi g u ra tion has a steam outlet on the right side of the
Outdoor Enclosure for con nect ing to steam dispersion unit piping. The optional internal steam dis tri bu tion con fi g u ra tion routes steam within the
Outdoor Enclosure and down through the enclosure pipe chase into a building.
2. There are four knockouts located on the right and left side of the enclosure. Knockout sizes are 1½" (hole dia. 50 mm) for STS models 25-100, and
2" (hole dia. 63.5 mm) for STS models 200-800. Run the electrical power into the en clo sure at these knockouts.
3. All piping from the STS unit to the steam outlet is stainless steel pipe. Depending on the application, tubing or DriSteem steam hose is recommended
for interconnecting piping from steam outlet to dispersion assembly.
4. Install a riser trap in the branch line leading to the humidifi er.
5. The preferred location for the STS steam control valve is inside the Outdoor Enclosure. If one of these valves must be located inside the building, it
must be located within 6' (1.8 m) of the humidifi er to reduce pressure drop.
6. See the dimensions in Table 13-1.
mc_012511_1635
K
Optional steam outlet
A
6.5"
DC-1476
Pipe chase
G
Table 12-1:
Outdoor Enclosure connection sizes
Description
Water makeup
(fi ll)
Drain3/4” (DN20)1” (DN25)
Condensate
return
Steam outletSee Table 27-1.
mc_012611_1017
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
12
25 – 100200 – 800
1/4” pipe thread (DN8) 1/4” pipe thread (DN8)
3/4” pipe thread (DN20) 3/4” pipe thread (DN20)
STS model
Table 12-2:
Outdoor Enclosure weights
Shipping weight*Operating weight*
STS model
lbskglbskg
25600272680308
50625284840381
100640290860390
20010504761650748
40011255101750794
800122555622501021
* Includes humidifi er
mc_012611_1016
Page 17
Outdoor Enclosure
FIGURE 13-1: OUTDOOR ENCLOSURE, TOP VIEW
Valve access door:
• Models 25-100 have one access door
• Models 200-800 have two access doors
Optional steam outlet
(exits enclosure through pipe chase)
C
INSTALLATION
E
J
Valve access door
Pipe chase extending 1" (25 mm) above enclosure fl oor
D
H
Enclosure drain
Standard steam outlet (exits enclosure here)
STS hu mid i fi er
DC-1478
B
mc_012611_0837
Table 13-1:
Outdoor Enclosure dimensions*
STS model
ItemDescription
AEnclosure height56.00142266.001676
BEnclosure width36.0091446.001168
C
Pipe chase position
D2.00573.5089
E
Pipe chase size
F8.0020310.00254
G
H18.6347322.00559
Steam pipe position
J14.5036820.50521
K12.2531111.00279
LEnclosure length60.00152478.001981
* See drawings in Figures 12-1 and 13-1.
mc_012611_1015
25–100200–800
inchesmminchesmm
4.501144.50114
20.0050832.00312
6.001528.50216
F
Valve section heater
Intake ventilation fan
Control panel
Control panel heater
Elec tri cal and cleanout access door
Intake ven ti la tion fan
Table 13-2:
STS Outdoor Enclosure electrical
specifications
Outdoor
Enclosure
without
heater
package
Outdoor
Enclosure
with heater
package
ELECTRICAL SPECIFICATIONS
VoltageCurrent
120 Vac,
50/60 Hz
120 Vac,
50/60 Hz
3.5 A10 A
13.5 A20 A
Maximum
disconnect
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Make-up water supply
piping (by installer)
(See Note 2)
Open to drain
Vacuum breaker (by installer)
120 V from unit
disconnect or other
source (See Note 1)
Normally closed
(fail closed) min
3/8" electric
valve (by installer)
Domestic water, 80 psig
(582 kPa) maximum
Open drain
(See Note 4)
Notes:
1. Insulate supply water piping to avoid dripping from condensation. To ensure that water does not remain in the fi ll line and freeze if there is a loss
of power, DriSteem recommends fi eld installing additional valves upstream of the fi ll valve in a conditioned space. Power these valves on the same
circuit that supplies the STS (as shown above); if the power goes off, water drains out of the fi ll line to prevent freezing.
2. Ensure that water lines are protected from freezing conditions.
• Install heat tracing and insulation on fi ll piping inside the Outdoor Enclosure.
• In extreme or critical applications in which the unlikely event of a water leak could cause severe damage, DriSteem recommends a thermostat
with a remote sensor on the fi ll line to cut power to the STS and safety valves to stop fi ll water to the STS and drain the fi ll piping when the
temperature is below freezing.
3. DriSteem recommends copper or iron drain piping for Outdoor Enclosures. On a loss of power the tank water will drain, but not be cooled by
the Drane-kooler because of the fi eld supplied safety shut-off valves. If it is critical to keep the Drane-kooler functional in the case of a power loss,
disconnect the Drane-kooler and relocate it down inside the conditioned space of the building. Pipe the supply water for the Drane-kooler before the
safety shut-off valves.
4. If copper or iron piping is used for both the fi ll and drain piping, these drains may be tied together. Locate 1" air gap only in spaces with adequate
temperature and air movement to absorb fl ash steam; otherwise, condensation may form on nearby surfaces. Refer to governing codes for drain
pipe size and maximum discharge water temperature.
mc_011311_1705
Humidifi er
Roof decking
Drain line, min. 1½" electric
valve (See Note 3)
Optional water seal (P-trap)
drain line, min. 1½" (DN40)
(See Note 3)
Normally open (fail open) min
1/2" electric valve (by installer)
Open drain
(See Note 4)
Disconnect (by installer); see Detail A
120V supply.
Refer to Table 13-2 for electrical requirements.
OM-7558
Heated building interior
120 V
N
Disconnect
box
Detail A
To valves
(by installer)
(See Note 1)
To STS
humidifi er
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
14
Page 19
Outdoor Enclosure
FIGURE 15-1: STS OUTDOOR ENCLOSURE, TOP VIEW
Valve access door:
• Models 25-100 have one access door
• Models 200-800 have two access doors
Optional steam outlet
(exits enclosure through pipe chase)
C
J
INSTALLATION
E
Valve access door
Pipe chase extending 1" (25 mm) above enclosure fl oor
D
H
Enclosure drain
Standard steam outlet (exits enclosure here)
STS hu mid i fi er
MOUNTING
B
DC-1478
F
Intake ventilation fan
Control panel
Control panel heater
Intake ven ti la tion fan
• Outdoor Enclosure must be level and positioned with enough clearance to
open access doors.
• Verify that position of pad or curb properly supports Outdoor Enclosure,
and that support structure dimensions coincide with unit dimensions.
• Locate unit so air intakes are not close to exhaust fan outlets, gasoline
storage, or other contaminants that could potentially cause dangerous
situations. Using or storing gasoline or other fl ammable vapors and liquids
in open containers in vicinity of Outdoor Enclosure is hazardous.
Valve section heater
Elec tri cal and cleanout access
door
Important note about STS Outdoor
Enclosure installation
• Install a riser trap in the branch line leading
to the humidifi er.
• The preferred location for the STS steam
control valve is inside the Outdoor Enclosure.
If one of these valves must be located inside
the building, it must be located within 6'
(1.8 m) of the humidifi er to reduce pressure
drop.
• When located on roof, Outdoor Enclosure air intakes must be a minimum
of 14" (356 mm) above roof to prevent intake of snow or splashed rain.
Position Outdoor Enclosure so prevailing winds do not blow into air intakes.
• Remove all shipping brackets and other packaging prior to installing the
unit.
• During transit, unloading, and setting of the unit, bolts and nuts may have
become loosened. Check that all nuts are tightened.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
15
Page 20
INSTALLATION
Outdoor Enclosure
MOUNTING (CONTINUED)
• There are four knockouts on the right and left side of the enclosure. It is
recommended that electrical power is run into enclosure at these knockouts.
• Outdoor Enclosure is designed for lifting by two methods:
– Preferred method of lifting is by forklift. This is only possible if the forks
extend across entire unit. Forks that do not extend across entire unit
could cause tipping, resulting in unsafe conditions or damage to the
unit.
– Alternative method of lifting is through unit’s channel base frame and/
or special lifting lug hooks installed on the unit. Use a load spreader of
suffi cient width to ensure that lifting cables clear sides of unit. If such a
spreader is not available, insert wood strips between cables and unit
where necessary. All four lifting points must be used; they are marked
“lift here” on the unit.
In both cases it must be lifted from the bottom base and kept level, and
it must not tip, fall, or twist. If unit is severely twisted during handling,
permanent damage could occur. It is installer’s responsibility to verify
handling equipment’s capability to safely handle Outdoor Enclosure.
• Outdoor Enclosure has two available steam distribution confi gurations:
– Standard confi guration is a steam outlet on one side of enclosure for
connecting to steam dispersion unit piping.
– Optional internal confi guration routes steam within Outdoor Enclosure
and down through pipe chase into building.
See the drawings beginning on Page 12.
FIGURE 16-1: OUTDOOR ENCLOSURE
MOUNTING OPTIONS
Flush
DC-1110
Curb
OM-1095
14"
(356 mm)
• Pipe chase is inside enclosure. Cover for pipe chase is provided to maintain
proper pressure in enclosure if this opening is not utilized. However, it is
recommended that this pipe chase be used for both supply water piping
and drain piping, in which case pipe chase cover should be removed.
Install insulation rated for 212 °F (100 °C) to completely fi ll area around
pipes to maintain proper enclosure pressure.
• When enclosure is pad mounted or when pipe chase cannot be used,
supply water and drain piping can be run through the knockouts —
preferably on side opposite utility connections.
• When ordered with heater package, two thermostat-controlled strip heaters
are provided to keep enclosure at constant minimum temperature: one
heater is in control cabinet section, and one heater is in front section.
• Enclosure drain is provided. In case of water leak, water will drain from
enclosure through this drain.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
16
Page 21
Outdoor Enclosure
INSTALLATION
MOUNTING (CONTINUED)
• Keypad/display with standard 5' (1.5 m) cable ships mounted to subpanel
in Outdoor Enclosure. Keypad/display must not come in contact with strip
heaters or block intake ventilation hood.
• If constant monitoring of unit is desired, or if unit is located in a severe
climate, a remote-mount keypad/display should be installed. Additional
cable lengths up to 500 feet (152 m) are available as an option for this
mounting confi guration.
• 16-gauge galvanized steel curbs (optional) are shipped unassembled for
ease of transporting to roof; they include all hardware for bolt-together
assembly, and all holes are matched before leaving factory. Curb must
be a minimum of 14" (356 mm) high. One 2" × 1/2" closed-cell curb
gasket with adhesive on one side is supplied with hardware. Gasket must
be installed between top of curb and base surface of Outdoor Enclosure
to prevent moisture from leaking into building from driving rain or melting
snow. Installation drawing is included.
• All piping from humidifi er to steam outlet is stainless steel pipe. Depending
on the application, tubing or DriSteem steam hose is recommended for
interconnecting piping from steam outlet to dispersion assembly.
• If ambient temperature in enclosure is below
50 °F (10 °C), the strip heaters power up.
Strip heaters remain on until enclosure
reaches 50 °F (10 °C) to ensure that
enclosure temperature does not drop below
the freezing point.
• When there is no call for humidity, an
aquastat maintains tank temperature at
the factory default of 70 °F (21 °C). This
temperature can be reset in the fi eld to be
from 40 to 180 °F (4 to 82 °C).
• When the ambient temperature in the
enclosure reaches 85 °F (29 °C), two
ventilation fans turn on to cool the electronic
components. A high limit is also provided
to power down the STS if the enclosure
temperature reaches 150 °F (66 °C). In
a high limit situation, the ventilation fans
continue to run and once the enclosure
temperature falls below 130 °F (54 °C), the
STS automatically resumes normal operation.
• A normally open drain valve is provided on
the STS Outdoor Enclosure to drain the tank
in the event of a power loss.
Humidifi er in Outdoor Enclosure
Electrical con nec tions
Remote Vapor-logic keypad
Drain piping
Water piping
Curb
Steam piping
Roof surface
OM-7464
mc_012611_1545
FIGURE 17-2:
OUTDOOR ENCLOSURE CLEARANCES
Left side:
36"
(914 mm)
Front:
36"
(914 mm)
Top:
Keep open
Back:
12"
(305 mm)
OM-955
mc_012611_1546
Right side:
24"
(610 mm)
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
17
Page 22
INSTALLATION
ALTERNATE WATER SEAL AND DRAIN VALVE PIPING
Piping:
Drain
The drain line piped from the humidifi er must be run to an approved sanitary
waste or suitable drain. If nonmetallic pipe or steam hose is used, it must be
rated for 212 °F (100 °C) minimum continuous operating temperature.
Minimum drain pipe sizes:
STS models 25 through 100: 3/4" (DN20) outside diameter.
STS models 200 through 800: 1" (DN25) outside diameter.
If the length of the drain piping exceeds 10' (3 m), increase the pipe size.
If combining multiple drain lines, ensure that proper common pipe sizing
practices are used.
Do not locate the humidifi er directly above a fl oor drain — skim and drain
water dumped into the fl oor drain will cause fl ash steam. This steam will rise
and saturate electrical components, adversely affecting component life and
performance.
TEMPERING DRAIN WATER
Governing codes may require that the 212 °F (100 °C) drain and skim water
from the humidifi er be tempered before it is discharged into the building drain
piping. The Drane-kooler® option will temper 6 gpm (22.7 L/m) of 212 °F
(100 °C) water to 140 °F (60 °C).
See the detailed piping drawings on Pages 22
through 25.
WATER SEAL
To allow normal operation and prevent steam from escaping through the drain
line, the installer must provide a water seal of a suffi cient height to contain the
pressure developed in the humidifi er system. See Table 27-1 for water seal
heights.
Drain piping after the water seal must be pitched a minimum of 1/8"/ft (1%)
toward the drain. Governing codes may require more pitch.
CONDENSATE PUMP
If the proximity of a drain requires the humidifi er drain and skim water to be
lifted by a pump, DriSteem offers a condensate pump option. A check valve
is required on the discharge of the pump. Electrical power for the pump is
independent of the humidifi er. Plug the pump into a wall outlet; an integral fl oat
switch turns the pump on and off.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
18
Page 23
INSTALLATION
Piping:
Drain
STS with RO/DI water option and manual drain has a pipe thread fi tting on the
drain valve and on the skim/overfl ow fi tting. Prior to dumping into a drain, the
installer needs to connect the drain and skim/overfl ow, provide a water seal of
height H1 (see Table 22-1), and pipe.
DRAIN CONNECTION
Note: This section applies to all tap/softened water STS models and all STS
models with the RO/DI and auto drain options.
The installer should install a water seal of height H1 (see Table 22-1).
The drain connection provided is a ProBite™ quick connection. Connect as
follows:
1. See Warning and Caution at right.
2. Cut drain line to length for insertion depth shown below for your ProBite
connector size. Cut must be clean and smooth.
3. Ream and de-burr drain line before connecting to ProBite connection.
Make sure drain line is clean, round, and free from damage.
4. Mark insertion depth on drain line according to table below for your
ProBite connection size.
5. Push drain line into ProBite connection to insertion depth marked in Step 4.
WARNING
Do not insert fi ngers or any body part
into ProBite connection openings
Insert only piping into ProBite
connection. Inserting fi ngers or any
body part could require emergency
medical attention for removal.
CAUTION
ProBite installation precautions
To avoid damage to the ProBite
connection:
• In addition to DriSteem drain
piping material requirements on
the facing page, ProBite fi ttings are
compatible only with copper, PEX,
CPVC or stainless steel.
• Do not solder within 10" (250 mm)
of the ProBite connection.
• Do not use heat or glue when
installing the ProBite connection.
FIGURE 19-1: DRAIN CONNECTION (ALL MODELS EXCEPT STS WITH RO/DI
WATER OPTION AND MANUAL DRAIN)
ProBite fi tting
Connector
size
D
OM-7644
Drain line
D
3/4"1 1/1627 mm
Insertion depth (D)
in.mm
1"1 5/1633 mm
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
19
Page 24
INSTALLATION
Piping:
WATER SUPPLY PIPING
All STS humidifi er models have a 1" (25 mm) internal air gap to prevent back
siphoning into a potable water system. However, some governing codes may
require additional protection such as a vacuum breaker or backfl ow preventer.
The supply water pressure range must be 25 to 80 psi (172 to 552 kPa).
TAP/SOFTENED WATER STS
Water supply assembly includes a strainer, needle valve, and fi ll solenoid —
1/4" pipe thread (DN8) connection. European models are provided with a
3/8" pipe thread (DN10) connection. Since the primary component of the
water supply assembly is a solenoid valve, there may be noise issues that
surface during a fi ll cycle.
During a fi ll cycle, the supply water drops the water temperature in the tank
and may collapse the steam, which can cause a low rolling sound. To diminish
this, adjust the needle valve to decrease the water fi ll rate and/or use hot
supply water.
In cases where water hammer occurs when the fi ll solenoid closes, a shock
arrester is recommended. Reducing the supply water pressure (minimum
25 psi [172 kPa]) or using fl exible tubing (rated 212 °F [100 °C], minimum
continuous operating temperature) may diminish the noise, but installing a
shock arrester is the best solution.
Fill
The minimum water conductivity for the probe-type water level control system to
work is 30 μS/cm.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
20
Page 25
INSTALLATION
Piping:
STS WITH RO/DI WATER OPTION
A fl oat valve controls the water supply — 1/4" pipe thread (DN8) connection.
European models are provided with a 3/8" pipe thread (DN10) connection.
For the end-of-season drain option, a solenoid valve is added on the inlet of the
fl oat valve. This option shuts off the fi ll water supply and drains the tank when
there is no demand for humidity for 72 hours. (This is a default setting, which is
adjustable. To modify this value, see the Vapor-logic Installation and Operation Manual.)
When using nonmetallic tubing for supply water, it must be rated for 212 °F
(100 °C) minimum continuous operating temperature. DriSteem recommends
installing a three-foot (914 mm) piece of noninsulated stainless steel pipe
directly off the humidifi er prior to connecting to the nonmetallic tubing. When
using nonmetallic tubing, DriSteem recommends the installer place a 2"
(50 mm) water seal/loop in the supply line to isolate steam during RO/DI
water system maintenance.
DriSteem recommends installing a strainer in the water supply line to prevent
clogging of the fl oat valve orifi ce. A strainer is highly recommended when
the humidifi er has the end-of-season drain option. The strainer will prevent
particulate from collecting at the solenoid valve seat.
Fill
If an STS humidifi er with the RO/DI water option is supplied with tap water, the
fl oat valve assembly will become clogged and run without water.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
21
Page 26
INSTALLATION
Piping:
FIGURE 22-1: FIELD PIPING OVERVIEW FOR TAP/SOFTENED WATER STS MODELS 25, 50, 100, 200, AND 400
3/4" pipe thread (DN20) dispersion unit condensate return inlet*
Water supply line (see Table 23-1); water pressure range
25 to 80 psi (172 to 582 kPa); water conductivity
30 μS/cm minimum
Optional condensate return
piping from evaporative
dispersion unit*
* Condensate return piping is
not needed for Ultra-sorb
Model XV dispersion unit, which
returns pressurized condensate
to the boiler. See the Ultra-sorb Model XV Installation Guide for
condensate piping requirements.
Tap/softened water, one heat exchanger
Water supply shut-off valve (by installer)
If water piping to humidifi er is nonmetallic, we
recommend a 2" (50 mm) metallic water seal or loop
in the supply line to isolate steam during maintenance
Condensate return to
nonpressurized system,
by gravity only
Trap
Shock arrester recommended to reduce water hammer
(by installer)
12"
(305
mm)
minimum
drop to
trap
Drain, skim, overfl ow
piping rated for 212 °F
(100 °C) (see sizes in
Table 23-1)
Pitch 1/8"/ft
(1%) toward drain
H1 (see
Table
22-1)
Steam outlet
Install level
Install level
Electric drain valve
Overfl ow line
DC-1451
If run is over 10' (3 m),
increase pipe to 1¼" (DN32)
1" (25 mm) air gap
Open fl oor drain.
See fi rst note below.
Water seal line
MUST be below
drain valve to ensure
humidifi er drains
correctly
Notes:
• Offset hu mid i fi er from fl oor drain to prevent fl ash steam from rising into the hu mid i fi er.
• Locate air gap only in spaces with adequate temperature and air movement to absorb fl ash steam; otherwise, condensation may form on nearby
surfaces. Refer to governing codes for drain pipe size and maximum discharge water temperature.
• Water supply inlet is more than 1" (25 mm) above skim/overfl ow port, eliminating the pos si bil i ty of backfl ow or si phon ing from tank. No additional
backfl ow prevention is required; however, governing codes prevail.
• Damage caused by chloride corrosion is not covered by your DriSteem warranty.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
22
Page 27
INSTALLATION
Piping:
FIGURE 23-1: FIELD PIPING OVERVIEW FOR TAP/SOFTENED WATER STS MODEL 800
3/4" pipe thread (DN20) dispersion unit condensate return inlet*
Shock arrestor (by installer) recommended to eliminate water hammer
Water supply line (see Table 23-1); water pressure range
25 to 80 psi (172 to 582 kPa); water conductivity
30 μS/cm minimum
6" (152 mm) minimum
* Condensate return piping is
not needed for Ultra-sorb
Model XV dispersion unit, which
returns pressurized condensate
to the boiler. See the Ultra-sorb Model XV Installation Guide for
condensate piping requirements.
Tap/softened water, two heat exchangers
Water supply shut-off valve (by installer)
Unions (by installer)
Optional condensate return
piping from evaporative
dispersion unit*
Air vent tube
®
Vacuum breaker
(by installer)
Strainers
From
steam
source
H2 (see
Table 22-1)
Condensate return to
nonpressurized system,
by gravity only
Drain, skim, overfl ow
piping rated for
212 °F (100 °C)
(see sizes in Table
23-1)
Pitch 1/8"/ft
(1%) toward drain
Steam outlet
Overfl ow
line
Install level
DC-1467
Install level
Electric drain valve
If run is over 10' (3 m),
increase pipe to 1¼" (DN32)
Water seal line MUST be
below drain valve to ensure
humidifi er drains correctly
1" (25 mm) air gap
Open fl oor drain.
See fi rst note below.
Notes:
• Offset hu mid i fi er from fl oor drain to prevent fl ash steam from rising into the hu mid i fi er.
• Locate air gap only in spaces with adequate temperature and air movement to absorb fl ash steam; otherwise, condensation may form on nearby
surfaces. Refer to governing codes for drain pipe size and maximum discharge water temperature.
• Water supply inlet is more than 1" (25 mm) above skim/overfl ow port, eliminating the pos si bil i ty of backfl ow or si phon ing from tank. No additional
backfl ow prevention is required; however, governing codes prevail.
• Damage caused by chloride corrosion is not covered by your DriSteem warranty.
• Dashed lines indicate provided by installer.
mc_010411_1550-tap
Table 23-1:
STS connection sizes
DescriptionConnection size
Water makeup (fi ll)1/4" pipe thread (DN8), all STS models
Drain
Steam outletVaries with capacity and dispersion type; see Table 27-1
Condensate return3/4" pipe thread (DN20)
Pressurized steam supply inlet and
return outlet
mc_010411_1555
3/4" (DN20) for STS models 25 through 100
1" (DN25) for STS models 200 through 800
See sizes in Tables 5-1 and 5-2.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
23
Page 28
INSTALLATION
Piping:
FIGURE 24-1: FIELD PIPING OVERVIEW FOR STS MODELS 25, 50, 100, 200, AND 400 WITH RO/DI WATER OPTION
Water supply line (see Table 25-1); water pressure range
25 to 80 psi (172 to 582 kPa); fi rst 3' (1 m) of supply line
must be rated for 212 °F (100 °C)
If water piping to humidifi er is nonmetallic, we recommend
a 2" (50 mm) metallic water seal or loop in the supply line
to isolate steam during maintenance
Optional condensate return
piping from evaporative
dispersion unit*
Air vent tube
* Condensate return piping is
not needed for Ultra-sorb®
Model XV dispersion unit,
which returns pressurized
condensate to the boiler.
See the Ultra-sorb Model
XV Installation Guide
for condensate piping
requirements.
RO/DI water option, one heat exchanger
Steam outlet
3/4" pipe thread (DN20)
dispersion unit condensate return inlet*
Condensate return to
nonpressurized system,
by gravity only
Trap
12"
(305
mm)
minimum
drop to
trap
H1 (see
Table
24-1)
Drain, skim, overfl ow piping
rated for 212 °F (100 °C)
(see sizes in Table 25-1)
Install level
Overfl ow line
Pitch 1/8"/ft
(1%) toward drain
Install level
DC-1459
Manual SST drain valve (electric drain valve
available for end-of-season drain option)
If run is over 10' (3 m),
increase pipe to 1¼" (DN32)
Water seal line MUST
be below drain valve to
ensure humidifi er drains
correctly
1" (25 mm) air gap
Open fl oor drain.
See fi rst note below.
Notes:
• Offset hu mid i fi er from fl oor drain to prevent fl ash steam from rising into the hu mid i fi er.
• Locate air gap only in spaces with adequate temperature and air movement to absorb fl ash steam; otherwise, condensation may form on nearby
surfaces. Refer to governing codes for drain pipe size and maximum discharge water temperature.
• Water supply inlet is more than 1" (25 mm) above skim/overfl ow port, eliminating the pos si bil i ty of backfl ow or si phon ing from tank. No additional
backfl ow prevention is required; however, governing codes prevail.
• Damage caused by chloride corrosion is not covered by your DriSteem warranty.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
24
Page 29
INSTALLATION
Piping:
FIGURE 25-1: FIELD PIPING OVERVIEW FOR STS MODEL 800 WITH RO/DI WATER OPTION
If water piping to humidifi er is nonmetallic, we recommend a
2" (50 mm) metallic water seal or loop in the supply line to
isolate steam during maintenance
Optional condensate
return piping from
dispersion unit*
* Condensate return
piping is not needed for
Ultra-sorb® Model XV
dispersion unit, which
returns pressurized
condensate to the boiler.
See the Ultra-sorb Model
XV Installation Guide
for condensate piping
requirements.
RO/DI water option, two heat exchangers
Water supply line (see Table 25-1); water
pressure range 25 to 80 psi (172 to 582 kPa)
Condensate return
to nonpressurized
system, by gravity
only
12"
(305 mm)
minimum
drop to
traps
Steam outlet
Pitch 1/8"/ft
(1%) toward drain
H1 (see
Table
24-1)
Drain, skim,
overfl ow piping
rated for 212 °F
(100 °C)
(see sizes in
Table 25-1)
Install level
Overfl ow
line
Install level
DC-1468
3/4" pipe thread (DN20)
dispersion unit condensate
return inlet*
Manual SST drain valve (electric drain valve
available for end-of-season drain option)
If run is over 10' (3 m), increase pipe to
1¼" (DN32)
Water seal line MUST be below
drain valve to ensure humidifi er
drains correctly
1" (25 mm) air gap
Open fl oor drain.
See fi rst note below
Notes:
• Offset hu mid i fi er from fl oor drain to prevent fl ash steam from rising into the hu mid i fi er.
• Locate air gap only in spaces with adequate temperature and air movement to absorb fl ash steam; otherwise, condensation may form on nearby
surfaces. Refer to governing codes for drain pipe size and maximum discharge water temperature.
• Water supply inlet is more than 1" (25 mm) above skim/overfl ow port, eliminating the pos si bil i ty of backfl ow or si phon ing from tank. No additional
backfl ow prevention is required; however, governing codes prevail.
• Damage caused by chloride corrosion is not covered by your DriSteem warranty.
• Dashed lines indicate provided by installer.
mc_010411_1550-di
Table 25-1:
STS connection sizes
DescriptionConnection size
Water makeup (fi ll)1/4" pipe thread (DN8), all STS models
Drain
Steam outletVaries with capacity and dispersion type; see Table 27-1
Condensate return3/4" pipe thread (DN20)
Pressurized steam supply inlet
and return outlet
mc_010411_1555
3/4" (DN20) for STS models 25 through 100
1" (DN25) for STS models 200 through 800
See sizes in Tables 5-1 and 5-2
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
25
Page 30
INSTALLATION
Piping:
Pressurized steam supply
The heat exchanger in the STS humidifi er is designed for a maximum steam
pressure of 15 psi (105 kPa). The steam valve, trap, and strainer are shipped
loose for fi eld installation.
Figure 26-1 shows piping from an overhead steam supply main with
condensate returned to a vented gravity fl ow return system. Note the steam
trap installed at the bottom of the branch feeding the steam valve of the STS.
Failure to install this trap will cause water hammer, which could damage the
STS heat exchanger.
Vacuum breakers are necessary to ensure that condensate can drain from the
heat exchanger when the steam valve closes.
Lifting condensate with pressurized steam is not recommended. Premature heat
exchanger failure and erratic control can occur when using pressurized steam
to lift condensate. A steam condensate pump is recommended when lifting
condensate in a pressurized system.
FIGURE 26-1: STEAM SUPPLY PIPING TO STS HUMIDIFIER
Note:
For STS 800 models, to guarantee steam output
capacities, a dedicated steam valve and steam
trap is required for each heat exchanger.
End of branch trap
(by installer)
Steam main
12"
Steam trap, required for proper
operation (by DriSteem)
Alternate vacuum
breaker position
12"
Vacuum breaker
(by installer)
Swing check valves
(by installer)
OM-941
Gravity condensate return
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
26
Page 31
INSTALLATION
Piping:
Humidification steam outlet
Table 27-1:
STS steam outlet sizes and types
STS model
25X
50XX
100XXX
200XXXX
400XXXX
800XXX
Note: For pipe thread steam outlet options, see DriCalc, DriSteem’s free sizing and selection
software, available at www. dristeem.com.
mc_010611_1100
FIGURE 27-3: FLANGE CONNECTION
Support member
Hose sizeFlange size
2" (DN50)3" (DN80)4" (DN100)5" (DN125)6" (DN150)
Support tubing from above to prevent
excessive weight on humidifi er outlet.
Allow for thermal expansion.
FIGURE 27-1: HOSE CONNECTION
Steam hose
Hose clamp
Steam outlet
connection
(tubing)
DC-1455
mc_010511_1748-tap
Note: Tap/softened water model shown.
FIGURE 27-2: TUBING CONNECTION
USING HOSE CUFF WITH CLAMPS
Tubing
Hose
clamps
6" (152 mm)
long hose cuff
Steam outlet
connection
(tubing)
DC-1458
mc_010511_1745-tap
Steam outlet connection (fl ange)
Notes:
• Dashed lines indicate provided by installer.
• Tap/softened water model shown.
DC-1456
mc_010511_1746-tap
Notes:
• Dashed lines indicate provided by installer.
• Tap/softened water model shown.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
27
Page 32
INSTALLATION
Wiring
WIRING DIAGRAM LOCATIONS
• Ladder style wiring diagrams (located inside control cabinet door)
show power, control, and humidifi er-to-control-cabinet interconnection
requirements.
• External connections diagrams (located inside control cabinet door) show
connection points to the microprocessor-based controller and wire terminals
for the following external safety and control devices: airfl ow proving
switches, high limits, transmitters, or humidistats.
All wiring must be in accordance with all governing codes and with STS wiring
diagrams.
ELECTRICAL INSTALLATION
Wiring and branch circuit protection is provided by the installer per the
National Electrical Code (NEC) or in Europe, IEC 60364. For power supply
and machine ground connections, size the wire using the 75 °C wiring table,
per the NEC (or IEC 60364). Then use copper conductors rated for a 105 °C
environment. The wiring from the control cabinet to the humidifi er must be
rated for 105 °C.
All STS humidifi ers have a 120V, single phase electrical supply for North
America or 230V, single phase electrical supply for Europe. Verify current
characteristics and capacity requirements against those listed on the name
plate.
WIRING REQUIREMENTS
WARNING
Electric shock hazard
Only qualifi ed electrical personnel
should perform fi eld wiring installation
procedures. Improper wiring or contact
with energized circuits can cause
property damage, severe personal
injury, or death as a result of electric
shock and/or fi re.
Do not open control cabinet until
electrical power is disconnected.
CAUTION
Damage from debris
When drilling penetrations in the
control cabinet, protect all internal
components from debris, and vacuum
out the control cabinet when fi nished.
Failure to comply with this directive
can damage sensitive electronic
com po nents, cause erratic operation
or failure, and void your DriSteem
warranty.
The length of wire from the control cabinet to the humidifi er must not exceed
50' (15 m). Run control wiring in dedicated, earthed, metal conduit or cable
trays or trunking that is separated from the building’s power wiring.
FIGURE 28-1: WATER LEVEL CONTROL WIRING FOR VAPOR-LOGIC
Brown or black, top probe rod (full water condition)
Orange or white, middle probe rod (refi ll water condition)
Violet or red, bottom probe rod: Low water condition,
tap/softened water
TOP
MID
LOW
Notes:
• See Outdoor Enclosure electrical
specifi cations in Table 13-2.
• Damage caused by chloride corrosion is not
covered by your DriSteem warranty.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
28
Page 33
Wiring
INSTALLATION
The control cabinet should be mounted in a location convenient for service with
a minimum of 36" (914 mm) clearance in front of the door.
The installer is responsible for making electrical connections at the power
terminals.
CONTROL WIRING
The following wiring methods for external low-voltage control wiring should
minimize electrical noise problems:
• Humidistat, RH transmitter, and temperature transmitter wiring must be
minimum 18-gauge (1 mm2) plenum rated, shielded (screened), twisted pair
wire with a bare drain wire for grounding.
• Airfl ow proving switch wiring must be minimum 18-gauge (1 mm2) stranded
wire run in conduit. The airfl ow proving switch can be wired using minimum
18-gauge (1 mm2) plenum rated, shielded (screened), twisted pair wire with
a bare drain wire for grounding.
• The shield (screen) wire should be connected to the shield (screen) ground
terminal/lug with a length less than 2" (51 mm). Do not ground the shield
(screen) wire on the humidistat or transmitter end.
• Water level control device, fi ll valve, and drain valve wiring must be
minimum 18-gauge stranded wire run in a separate conduit from power
wires. DO NOT USE SHIELDED (SCREENED) CABLE FOR WATER LEVEL
CONTROL DEVICES.
Important: Failure to follow these wiring
procedures can result in erratic operation or
failure.
This product has been tested at the factory for
proper operation. Product failures resulting from
faulty handling, incorrect wiring, or shorting of
wires together on external components are not
covered under your DriSteem warranty. Review
information and diagrams before proceeding.
• The tank temperature sensor can be run with 18-gauge (1 mm2) stranded
wire if the control cabinet is located within 10' ( 3 m) of the humidifi er. For
wire lengths of 10' to 50' (3 m to 15 m), use 18-gauge (1 mm2) plenum
rated, shielded (screened), twisted pair wire with a bare drain wire for
grounding.
GROUNDING REQUIREMENTS
The approved earth ground must be made with solid metal-to-metal connections
and must be a good conductor of radio frequency interference (RFI) to earth
(multistranded conductors).
Ground wire should be the same AWG (mm2) size as the power wiring or
sized per NEC requirements (in Europe, IEC 60364 requirements).
When the control cabinet is mounted remotely from the humidifi er, a ground
wire is necessary from the machine ground lug on the humidifi er to the
machine ground lug in the control cabinet. The bonding machine ground wire
should be no less than 14-gauge AWG (mm2) or sized per NEC or IEC 60364
requirements.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
29
Page 34
INSTALLATION
Sensor placement
SENSOR LOCATION IS CRITICAL
Sensor location has a signifi cant impact on humidifi er performance. See the
recommendations below and Figure 30-1.
Note: DriSteem recommends that you do not interchange room and duct
humidity devices. Room humidity devices are calibrated with zero or
little airfl ow, whereas duct humidity devices require air passing across
them.
Recommended humidity control (transmitter/humidistat) locations:
A Ideal. Ensures the best uniform mix of dry and moist air with stable
temperature control.
B Acceptable, but room environment can affect controllability, such as when
sensor is too close to air grilles, registers, or heat radiation from room
lighting.
C Acceptable. Provides uniform mixture of dry and moist air. If extended time
lag exists between humidity generation and sensing, extend sampling time.
D Acceptable (behind wall or partition) for sampling entire room if sensor is
near an air exhaust return outlet. Typical placement for sampling a critical
area.
E Not acceptable. These locations might not represent actual overall
conditions in the space.
Other factors affecting humidity control
Humidity control involves more than the
controller’s ability to control the system. Other
factors that play an important role in overall
system control are:
• Size of humidifi cation system relative to load
• Overall system dynamics associated with
moisture migration time lags
• Accuracy of humidistats and humidity
transmitters and their location
• Dry bulb temperature accuracy in space or
duct
• Velocities and airfl ow patterns in ducts and
space environments
• Electrical noise or interference
mc_072011_1656
F Not acceptable. Do not place sensors near windows, door passageways,
or areas of stagnant airfl ow.
Recommended safety (airfl ow and high limit) sensor location:
G Best sensing location for high limit humidistat or humidity sensor and airfl ow
proving switch.
mc_072011_1655
FIGURE 30-1: RECOMMENDED SENSOR LOCATIONS
Outside air
Relief air
Damper control
A
DC-1084M
mc_060508_0750
Return air
E
C
Window
F
Doorway
Air handling
unit
D
B
E
8' to 12'
(2.4 m to 3.7 m)
min.
Wall or
partition
F
F
Window
High limit humidistat or high limit transmitter
(set at 90% RH maximum) for VAV applications
Airfl ow switch or differential pressure switch
(sail type recommended for VAV applications)
G
Vapor absorption has taken place
Point of vapor absorption
Humidifi er dispersion assembly
Turning vanes
Temperature compensation option: Place a temperature compensation
sensor on the lower corner of the inside surface of double-pane window
glass on north- or northeast-facing window.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
30
Page 35
INSTALLATION
Dispersion:
Selecting the dispersion assembly location
DriSteem humidifi ers operate with several types of dispersion assemblies for
open spaces and for ducts and air handling units.
Dispersion assemblies in ducts and air handling units must be positioned where
the water vapor being discharged is carried off with the airstream and is
absorbed before it can cause condensation or dripping.
• Non-wetting distance is the dimension downstream from the leaving
side of the steam dispersion assembly to the point where wetting will
not occur, although wisps of steam may be present. This distance was
calculated during humidifi cation system design and is dependent on
several application parameters. To determine your dispersion assembly’s
non-wetting distance, consult your system’s design engineer or project
documentation. Non-wetting distance can also be calculated using
DriSteem’s DriCalc sizing and selection software, available at www.
dristeem.com. Note that your current design conditions may vary from
conditions used for system design.
• In general, the dispersion assembly is best placed where the air can absorb
the moisture being added without causing con den sa tion at or after the unit.
This normally will be after the heating coil or where the air tem per a ture is
highest.
WARNING
Hot surface and steam hazard
Dispersion tube, steam hose or tubing
can contain steam, and surfaces can
be hot. Discharged steam is not visible.
Contact with hot surfaces or air into
which steam has been discharged can
cause severe personal injury.
mc_060110_1555
Important:
Failure to follow the recommendations in this
section can result in excessive back pressure on
the humidifi er. This will result in unacceptable
humidifi cation system performance such as
leaking gaskets, blown water seals, erratic
water level control, and spitting condensate
from dispersion tubes.
mc_060210_0843
• Place the dispersion assembly such that absorption will occur
– before the intake of a high effi ciency fi lter, because the fi lter can remove
the visible moisture and become waterlogged;
– before coming in contact with any metal surface;
– before fi re or smoke detection devices;
– before a split in the duct; otherwise, the dispersion assembly can direct
more moisture into one duct than the other.
• When draining dispersion condensate to an open drain, provide a 1"
(25 mm) air gap between the condensate drain piping and the drain.
Locate the gap only in spaces with adequate temperature and air movement
to absorb fl ash steam; otherwise, condensation may form on nearby
surfaces.
mc_060210_0838
OVERHEAD INSTALLATION
Water piping and humidifi ers should not be installed above expensive
equipment. A condensing or leaking water pipe or other accidental water
spillage could cause serious damage to the equipment below.
When such an installation cannot be avoided, install a galvanized drip pan
under the humidifi er piping, valve, etc. to catch and drain away unintended
water. See Figure 8-4.
It is advisable to terminate the drain above an open fl oor drain. The overfl ow
from the STS should be piped separately to a fl oor drain. Do not drain the STS
directly into the drip pan.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
31
Page 36
INSTALLATION
Dispersion: Interconnecting piping requirements
• The steam outlet on the humidifi er is sized to the output of the humidifi er.
DO NOT use steam hose or interconnecting piping with an inside diameter
smaller than the humidifi er steam outlet.
• See maximum steam carrying capacities in Table 33-1.
• See the steam loss data in Table 33-2.
• See Table 36-2 for interconnecting tubing and pipe pitch requirements
for single tube and multiple tube applications. See Table 41-1 for
interconnecting tubing and pipe pitch requirements for Rapid-sorb
applications.
• If the humidifi er must be located higher than the dispersion assembly, use
the recommended installation shown in Figure 34-1.
• For single tube applications, see capacities in Table 35-1.
CONNECTING TO HUMIDIFIER WITH STEAM HOSE
• Support steam hose to prevent sags, or low spots, and to maintain a
minimum pitch of 2"/ft (15%) back to the humidifi er.
• Use DriSteem steam hose. Other manufacturers of steam hose may use
unacceptable release agents or material mixes that can affect humidifi er
system performance adversely. Using hose from alternative manufacturers
increases the possibility of tank foaming and accelerated aging. Foaming
causes condensate discharge at the dispersion assembly.
Important:
Failure to follow the recommendations in this
section can result in excessive back pressure on
the humidifi er. This will result in unacceptable
humidifi cation system performance such as
leaking gaskets, blown water seals, erratic
water level control, and spitting condensate
from dispersion tubes.
mc_060210_0843
• Do not use steam hose in outdoor applications.
• Do not insulate steam hose. Insulation causes accelerated heat aging,
causing the steam hose to become hard and susceptible to failure due to
cracks.
CONNECTING TO HUMIDIFIER WITH TUBING
• Support interconnecting piping between the humidifi er steam outlet and the
dispersion system with pipe hangers. Failure to properly support the entire
steam piping weight may cause damage to the humidifi er tank and void the
warranty.
• 90° elbows are not recommended; use two 45° elbows, 1' (0.3 m) apart.
• Insulat tubing to reduce the loss in output caused by condensation.
mc_060310_1145
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
32
Page 37
Dispersion: Interconnecting piping requirements
Table 33-1:
Maximum steam carrying capacity and length of interconnecting steam hose or tubing
Steam hose
1
Copper or stainless steel tubing
INSTALLATION
Hose I.D.Maximum capacity Maximum length
2
Tubing sizeMaximum capacity 3
Maximum developed
length
inchesDNlbs/hrkg/hftminchesDNlbs/hrkg/hftm
250250113103250220100309
3 5 80 54502048024
4 5 100 575034010030
1. When using steam hose, use DriSteem steam hose for best results.
Field-supplied hose may have shorter life and may cause foaming in
the evaporating chamber resulting in condensate discharge at the
dispersion assembly. Do not use steam hose for outdoor applications.
2. Maximum recommended length for steam hose is 10' (3 m). Longer
distances can cause kinking or low spots.
5
5
5
6
3. Insulate tubing to minimize loss of capacity and effi ciency.
4. Developed length of tubing equals measured length plus 50% of
measured length, to account for fi ttings.
Longer tubing lengths are possible at capacities lower than listed
maximums. Consult factory.
5. Requires fl ange connection.
125
150
5
140063510030
5
2300104310030
Note: Capacities and lengths in this table are based on total maximum pressure drop in hose or tubing of 5" wc (1250 Pa).
mc_091410_1050-STS
Table 33-2:
Steam loss of interconnecting steam hose or tubing
Steam loss
Insulation thickness
Description
Nominal hose or tubing size
NoninsulatedInsulated
4
inchesDNlbs/hr/ftkg/h/mlbs/hr/ftkg/h/minchesmm
1½400.150.22N/AN/AN/AN/A
Hose
2500.200.30N/AN/AN/AN/A
1½400.110.160.0200.0302.050
2500.140.210.0250.0372.050
3800.200.300.0300.0452.564
Tubing
41000.260.390.0300.0453.076
51250.310.460.0350.0523.076
61500.360.540.0390.0583.076
Note: Data based on an ambient air temperature of 80 °F (27 °C), fi berglass insulation, and copper tubing.
mc_051310_1216
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
33
Page 38
INSTALLATION
Dispersion: Drip tee installation
Install a drip tee as shown below when the humidifi er is mounted higher than
the dispersion assembly, when interconnecting hose or tubing needs to go over
an obstruction, or when interconnecting piping runs are long.
Important: Steam hose must be supported to prevent sagging or low spots.
FIGURE 34-1: DRIP TEE INSTALLATION (PIPING OVER AN OBSTRUCTION)
90° long sweep or
two 45° elbows
Insulate tubing and to
reduce steam loss
To dispersion device
6" (150 mm)
minimum
8" (200 mm)
minimum
Pitch
Obstruction
DC-1470
STS humidifi er
Tubing drip tee, by installer.
DriSteem part number for 304 stainless steel
in-line tee: 2" diameter (DN50): No. 162712
3/4" (DN20)
1" (25 mm) air gap
Funnel or fl oor drain
Notes:
• Locate air gap only in spaces with adequate temperature and air movement to absorb fl ash
steam; otherwise, condensation may form on nearby surfaces. Refer to governing codes for
drain pipe size and maximum discharge water temperature.
• Support steam hose so there are no sags or low spots.
• Dashed lines indicate provided by installer.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
34
Page 39
Dispersion: Single tube and multiple tube
DISPERSION TUBE MOUNTING
• See the hose kit sizes in Table 35-1 for single tube applications.
• Orient dispersion tube(s) so that tubelets (steam orifi ces) point up.
• See Table 36-2 for dispersion tube pitch requirements.
• When mounting the humidifi er above the level of the dispersion tube(s), see
drip tee installation in Figure 34-1.
CONDENSATE DRAIN PIPING
• Minimum diameter (ID) for draining from one or two dispersion tubes:
3/4" (DN20)
• Minimum diameter (ID) for draining from three or more dispersion tubes:
1" (DN25)
• Condensate drain piping must be rated for 212 °F (100 °C) continuous
operating temperature.
• Condensate drain line must be piped as shown in the fi gures on the
following pages. Provide a 6" (152 mm) drop prior to a 5" (127 mm)
water seal to:
INSTALLATION
− Ensure drainage of condensate from the header
− Keep steam from blowing out of the drain line
• After the water seal, run the drain line to an open drain with a 1" (25
mm) vertical air gap. Cut the drain line at a 45° angle on the end
above the drain to permit a direct stream of water into the drain pipe
while maintaining a 1" (25 mm) air gap. Locate air gap only in spaces
with adequate temperature and air movement to absorb fl ash steam, or
condensing on nearby surfaces may occur.
• All drain lines must be installed and sized according to governing codes.
mc_020111_0908
Table 35-1:
Single dispersion tube capacities
Insulated
Tube size
inchesDNlbs/hrkg/hlbs/hrkg/hlbs/hrkg/hlbs/hrkg/h
1½402913.26529.52812.76228.2
2506529.59744.16228.29342.3
(High-Effi ciency Tubes)
Without drainWith drainWithout drainWith drain
Uninsulated
Notes:
• Single dispersion tube available with face width between 6" (152 mm) up to 120" (3048 mm)
in 1" (25 mm) increments.
• If face width is <19" (483 mm), tube capacity may be reduced. Consult DriSteem or see
DriCalc for the correct capacity.
• Hose kits are available that include dispersion tube, 10 ft (3 m) of steam hose, and hardware
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
35
Page 40
INSTALLATION
Dispersion: Single tube and multiple tube
FIGURE 36-1: SINGLE TUBE DISPERSION WITHOUT CONDENSATE DRAIN
Duct
Single dispersion tube without
condensate drain
Steam hose or tubing. Insulate tubing
to reduce steam loss. Do not insulate
steam hose.
STS humidifi er
Pitch*
Secure and seal duct
escutcheon plate
90° long sweep or
two 45° elbows
OM-7512
Table 36-1:
3/8" (M10)
mounting nut
Tube pitch 2"/ft (15%)
Dispersion tube escutcheon plate
Dashed lines indicate provided by installer
* Pitch steam hose or tubing toward humidifi er:
– 2"/ft (15%) when using steam hose
– 1/8"/ft (1%) when using tubing
(diameter)
Dispersion tube
escutcheon plate
B
A
B
dimensions
for 2" tube
inchesmm
A2.0352
B5.00127
Table 36-2:
Pitch of dispersion tube(s) and interconnecting piping for Single tube or multiple tube evaporative dispersion units*
Condensate drain
Without drain
Type of
interconnecting piping
Steam hose2" (DN50)
Tubing2" (DN50)
Diameter of
dispersion tube and
interconnecting piping
Pitch of
interconnecting piping
2"/ft (15%)
toward humidifi er
1/8"/ft (1%)
toward humidifi er
Pitch of
dispersion tube(s)
2"/ft (15%)
toward humidifi er
Pitch of
condensate drain
No drain
Steam hose2" (DN50)
With drain
Tubing2" (DN50)
* When piping over an obstruction, see the drip tee installation illustration on Page 38.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
36
2"/ft (15%)
toward humidifi er
1/4"/ft (2%)
toward humidifi er
1/8"/ft (1%)
toward
condensate
drain
1/4"/ft (2%)
toward fl oor drain or
toward humidifi er if
humidifi er is below
dispersion unit
Page 41
Dispersion: Single tube and multiple tube
FIGURE 37-1: SINGLE TUBE DISPERSION WITH CONDENSATE WASTED TO FLOOR DRAIN
INSTALLATION
Steam hose or tubing. Insulate
tubing to reduce steam loss.
Do not insulate steam hose.
90° long sweep or
two 45° elbows
STS humidifi er
Notes:
1. Locate air gap only in spaces with adequate temperature and air movement to absorb fl ash steam, or condensing on nearby surfaces my occur.
Refer to governing codes for drain pipe size and maximum discharge water temperature.
2. Pitch steam hose or tubing toward humidifi er:
– 2"/ft (15%) when using steam hose
– 1/2"/ft (5%) when using 1½" tubing
– 1/4"/ft (2%) when using 2" tubing
3. Dashed lines indicate provided by installer
Secure and seal
escutcheon plates
Pitch
(see Note 2 below)
6" (152 mm)
recommended
Water seal
5" (127 mm)
1" (25 mm)
air gap
Duct
1/4" (DN8) pipe
thread
Condensate drain tube, by installer, minimum 3/4"
(DN20); must be suitable for 212 °F (100 °C) water
FIGURE 37-1: DISPERSION TUBE AND
CONDENSATE DRAIN ESCUTCHEON
PLATES
Dispersion tube plate
A
(diameter)
B
B
Condensate drain plate
D
(diameter)
C
D
OM-351c
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
37
Page 42
INSTALLATION
Dispersion: Single tube and multiple tube
FIGURE 38-1: SINGLE TUBE WITH CONDENSATE RETURNED TO HUMIDIFIER
Steam hose or tubing
90% long sweep or two 45° elbows
Secure and seal
escutcheon plates
Pitch*
Duct
Dispersion tube
Mounting nut, 3/8" (M10)
6" (152 mm)
minimum
6" (152 mm)
minimum
STS humidifi er
H2 (see Table
24-1)
3/4" (DN20) condensate return
connection (on face plate)
Dashed lines indicate provided by installer
* Pitch steam hose or tubing toward humidifi er:
– 2"/ft (15%) when using steam hose
– 1/2"/ft (5%) when using 1½" tubing
– 1/4"/ft (2%) when using 2" tubing
FIGURE 38-2: SINGLE TUBE DISPERSION WITH CONDENSATE DRAIN
Thermal-resin tubelets
(steam orifi ce inserts)
1/2" (13 mm)
Condensate drain tube, by installer, 3/4" DN20 minimum. Return line
piping material must be suitable for 212 °F (100 °C) water. Note:
Condensate may be returned to the humidifi er or wasted to a drain.
See the previous page for piping condensate to a drain.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
38
Movable escutcheon plate. Plate
can be mounted within limits of
2.5" (64 mm).
Mounting bracket
1/2" O.D. (DN15) condensate drain
Page 43
Dispersion: Single tube and multiple tube
FIGURE 39-1: MULTIPLE TUBE WITH CONDENSATE WASTED TO FLOOR DRAIN
INSTALLATION
Steam hose or tubing
90° long sweep or two 45° elbows
STS humidifi er
DC-1048a
Dashed lines indicate provided by installer
* Pitch steam hose or tubing toward humidifi er:
– 2"/ft (15%) when using steam hose
– 1/2"/ft (5%) when using 1½" tubing
– 1/4"/ft (2%) when using 2" tubing
Secure and seal
escutcheon plates
Pitch*
Water seal
5" (127 mm)
1" (25 mm)
air gap
Dispersion tube
6"
(152 mm)
Duct
¼" pipe
thread (DN8)
Condensate drain tube provided by
installer, 3/4" (DN20) minimum
1/2" (13 mm) air vent
Open drain required.
Locate air gap only in spaces with adequate temperature
and air movement to absorb fl ash steam; otherwise,
condensation may form on nearby surfaces. Refer to
governing codes for drain pipe size and maximum
discharge water temperature.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
39
Page 44
INSTALLATION
Dispersion: Rapid-sorb
Read all dispersion instructions in this manual, and follow the installation
instructions below:
• Unpack shipment and verify receipt of all Rapid-sorb components
with packing list. Report any shortages to DriSteem immediately. The
components typically include the following:
– Multiple dispersion tubes
– Header
– 3/4" × 2" (19 mm × 51 mm) L-bracket
Note: Dispersion tubes, header, and L-bracket are each tagged with the
customer requested identifi cation number.
– A single duct escutcheon plate the size of the header
– Slip couplings or hose cuffs and clamps
– Accessories such as duct plates, slip couplings, or hose cuffs
– Bolts and washers for mounting the dispersion tubes to the bracket
• L-bracket mounting holes (see note at left):
– L-bracket 50" (1270 mm) long or shorter has a mounting hole 4" (102
mm) from each end for mounting the L-bracket to the duct or air handler
wall.
– L-bracket longer than 50" (1270 mm) has an additional mounting hole
in the center.
Note: Hardware for mounting the L-bracket to the duct or air handler wall
and the hardware for the header support bracket is not provided.
• Select an installation location that provides necessary access in and around
the ductwork or air handler.
CAUTION
Operate Rapid-sorb within rated steam
capacity
Excessive steam fl ow to the Rapid-sorb
steam dispersion assembly can
cause condensate to exit the tubelets,
which can cause water damage and
standing water in the duct or air
handler.
To avoid condensate exiting the
tubelets, do not operate the Rapid-sorb
beyond its rated capacity.
mc_060210_0940
Important: Before marking and
drilling holes in the duct or air handler, refer
to ALL pitch re quire ments for the Rapid-sorb
as sem bly you received (see Table 41-1). The
size, quan ti ty, and location of penetrations
are determined by the dimensions and
confi guration of the Rapid-sorb assembly you
received.
mc_060210_0937
• The Rapid-sorb typically is installed centered side to side in a duct, or is
installed across the face of a coil in an air handler.
• The center line of the outer dispersion tubes should never be closer than
4.5" (114 mm) from the side of the ductwork or air handler wall.
• The following instructions are for a typical Rapid-sorb installation —
horizontal-airfl ow duct with Rapid-sorb header either inside or outside
the duct. See the DriCalc Installation Guides library or contact your
representative/distributor or DriSteem for installation instructions for air
handler or vertical airfl ow applications.
mc_060210_0945-NA
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
40
Page 45
Dispersion: Rapid-sorb
INSTALLATION
PITCH REQUIREMENTS
• For Rapid-sorb with the header outside a horizontal-airfl ow duct, consider
the following:
– 1½" (DN40) dispersion tubes: Use a fastener of suffi cient length to
ac com mo date the 1/8"/ft (1%) pitch requirements toward the 3/4"
pipe thread (DN20) header drain fi tting.
– 2" (DN50) dispersion tubes: The bracket can be mounted fl ush to the
ductwork. The 1/8"/ft (1%) pitch typically can be accomplished in the
length of the hose cuffs used to connect the tubes to the header.
• See Table 41-3 and the drawings on the following pages for pitch
requirements.
mc_060210_0953-NA
Table 41-1:
Rapid-sorb tube capacities*
Tube diameter
inchesDNlbs/hr kg/h lbs/hr kg/h
1½404319.54018.2
2508036.47735
* Capacities shown are for horizontal airfl ow.
See DriCalc for vertical airfl ow capacities.
If face height is <22” (559 mm), tube
quantity per panel may need to increase to
compensate for reduced capacity of short
tubes. Consult DriSteem or see DriCalc for
the correct calculation.
Insulated
(High-Effi ciency
Tubes)
Uninsulated
Table 41-2:
Rapid-sorb header capacities
Header capacityHeader diameter
lbs/hrkg/hinchesDN
≤ 250≤ 113250
251-500114-227380
501-800228-3634100
801-1300364-5915125
1301-2100 592-9556150
mc_060210_0936
Table 41-3:
Pitch of interconnecting piping, dispersion tubes, and headers for Rapid-sorb evaporative dispersion units
Airfl ow
Horizontal
Vertical
mc_020111_0945
Type of
interconnecting piping
Steam hose1½" (DN40), 2" (DN50)
Tubing
Steam hose1½" (DN40), 2" (DN50)
Tubing
Diameter of
interconnecting piping
1½" (DN40), 2" (DN50),
3" (DN80), 4" (DN100),
5" (DN125), 6" (DN150)
1½" (DN40), 2" (DN50),
3" (DN80), 4" (DN100),
5" (DN125), 6" (DN150)
Pitch of
interconnecting piping
2"/ft (15%)
toward
Rapid-sorb
1/8"/ft (1%)
toward
Rapid-sorb
2"/ft (15%)
toward
Rapid-sorb
1/8"/ft (1%)
toward
Rapid-sorb
Pitch of
dispersion tubes
Vertically
plumb
2"/ft
toward
header
Pitch of
header
1/8"/ft (1%)
toward
condensate
drain
1/8"/ft (1%)
toward
condensate
drain
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
41
Page 46
INSTALLATION
Dispersion: Rapid-sorb
FIGURE 42-1: RAPID-SORB INSTALLED IN A HORIZONTAL AIRFLOW WITH HEADER OUTSIDE THE DUCT
Position L-bracket so that fl ange is upstream of dispersion
tubes. This drawing shows the L-bracket positioned for
airfl ow back to front
Dispersion tube
Point tubelets (steam orifi ces) perpendicular to airfl ow
Airfl ow
Duct
90° long sweep or
two 45° elbows
Steam hose or tubing
* Pitch steam hose or tubing toward Rapid-sorb:
– 2"/ft (15%) when using steam hose
– 1/8"/ft (1%) when using tubing
HEADER OUTSIDE OF DUCT, HORIZONTAL AIRFLOW
Slip coupling or
hose cuff
Pitch*
Pitch header toward
drain 1/8"/ft (1%)
STS humidifi er
DC-1471
3/4" pipe thread (DN20)
condensate drain
3/4" (DN20) copper
1" (25 mm)
air gap
1. Mark and cut holes in the ductwork for the dispersion tubes. Use the
L-bracket as a tem plate to mark the holes on the duct floor.
2. Temporarily, loosely suspend or support the header below the final
location. Vertical balance point of the dispersion tube length dictates
where the header should be suspended or temporarily supported.
Support bracket
6" (152 mm)
5" (127 mm)
Open drain required. Locate air gap only in
spaces with adequate temperature and air
movement to absorb fl ash steam; otherwise,
condensation may form on nearby surfaces.
Refer to governing codes for drain pipe size
and maximum discharge water temperature.
3. Mount the dispersion tubes to the header with the slip coupling or hose cuff
(provided).
• When installing slip couplings for 1½" (DN40) dispersion tubes, take
care not to shear the O-rings.
• Set the slip coupling on the header stub or dis per sion tube so the O-ring
is resting on the face of the tubing.
• Rotate the slip coupling as you push it onto the tubing.
• The O-rings are lubricated at the factory. If additional lubrication is
necessary, DO NOT use a petroleum-based lubricant.
4. Position the flange of the L-bracket so it is upstream of the tubes when the
assembly is raised and fastened into po si tion. Fasten the L-bracket to the
end of the dispersion tubes with the provided bolt, lock washer, and flat
washer.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
42
Page 47
Dispersion: Rapid-sorb
INSTALLATION
5. Before tightening the L-bracket bolts to the dispersion tubes:
• For 1½" (DN40) dis per sion tubes:
– Dispersion tube will rotate in slip coupling. Verify that dispersion tube
orifi ces are directed perpendicular to airfl ow.
– Dispersion tube and slip coupling must be fully engaged on header
stub for O-rings to provide a seal.
• For 2" (DN50) dispersion tubes:
Before securing hose cuff in place with hose clamps on dis per sion tube
and the header stub, verify that dis per sion tube orifi ces are directed
perpendicular to airfl ow.
6. Slide the assembly up until the L-bracket aligns with the mount ing holes in
the duct.
• For 1½" (DN40) dispersion tubes:
– Header pitch is duplicated in the L-bracket.
– Dispersion tube and slip coupling must be fully engaged on header
stub for O-rings to provide a seal.
– High end of L-bracket can be fastened tight to duct or air handler.
– Fastener on low end of L-bracket must be long enough to compensate
for pitch. Use a nut on both sides of L-bracket and duct or air handler
for stability.
• For 2" (DN50) dis per sion tubes:
– Fasten bracket to top of duct and use hose cuffs to compensate for
header pitch.
– Before securing hose cuffs with hose clamps on dispersion tube and
header stub, verify that header pitch, 1/8"/ft (1%) toward drain, is
maintained.
Note:
See Page 46 for steam supply and condensate
drain line connection instructions.
7. Permanently secure both ends of header, and verify that header pitch,
1/8"/ft (1%) toward drain, is maintained.
8. Verify that all fasteners are secure:
• L-bracket to duct
• Dispersion tubes to L-bracket
• Hose clamps on 2" (DN50) tubes
9. Secure and seal the dispersion tube escutcheon plate and condensate
drain tube escutcheon plate around the respective tubes, if applicable.
mc_060210_1015
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
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Page 48
INSTALLATION
Dispersion: Rapid-sorb
FIGURE 44-1: RAPID-SORB INSTALLED IN A HORIZONTAL AIRFLOW WITH HEADER INSIDE THE DUCT
Position L-bracket so that fl ange is upstream of dispersion
tubes. This drawing shows the L-bracket positioned for
airfl ow back to front
Dispersion tube
Point tubelets (steam orifi ces) perpendicular to airfl ow
Airfl ow
90° long sweep or
two 45° elbows
Steam hose or tubing
* Pitch steam hose or tubing toward Rapid-sorb:
– 2"/ft (15%) when using steam hose
– 1/8"/ft (1%) when using tubing
HEADER INSIDE OF DUCT, HORIZONTAL AIRFLOW
Slip coupling
or hose cuff
Pitch*
Pitch header
toward drain
1/8"/ft (1%)
STS humidifi er
DC-1472
3/4" pipe
thread (DN20)
condensate drain
3/4"
(DN20)
copper
1" (25 mm)
air gap
1. Mark and cut holes in ductwork or air handler for steam header
pen e tra tion, con den sate drain piping, and head er support bracket fastener.
Allow 1/8"/ft (1%) header pitch toward the support bracket when you drill
the hole for the header support bracket fastener.
Duct
5" (127 mm)
Open drain required. Locate air gap only in
spaces with adequate temperature and air
movement to absorb fl ash steam; otherwise,
condensation may form on nearby surfaces.
Refer to governing codes for drain pipe size
and maximum discharge water temperature.
Support bracket
6" (152 mm)
2. Loosely fasten the header in place.
3. Rotate the header 90° so the header stubs point hor i zon tal ly in the duct.
When installing in an air handler, the rotation of the header is often less
than 90°. Typically, due to the condensate drain piping re quire ments, the
header can be set on the floor of the air handler, assembled in the vertical
position, and then raised and mounted in place.
4. Mount the dispersion tubes on the header with the slip couplings or hose
cuffs:
• When installing slip couplings for 1½" (DN40) dispersion tubes, take
care not to shear O-rings.
• Set slip coupling on header stub or dis per sion tube so O-ring is resting
on face of tubing.
• Rotate slip coupling while pushing it onto the tubing.
• O-rings are lubricated at factory. If additional lubrication is necessary,
DO NOT use petroleum-based lubricant.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
44
Page 49
Dispersion: Rapid-sorb
INSTALLATION
5. Allow the dispersion tubes to rest against the bottom of the duct.
6. Position the flange of the L-bracket so it is upstream of the tubes when the
assembly is rotated into position. Fasten the L-bracket to the end of the
dispersion tubes with the provided bolt, lock washer, and flat washer.
7. Rotate the assembly up until the L-bracket aligns with the mounting holes in
the duct or air handler.
• For 1½" (DN40) dispersion tubes:
– Header pitch is duplicated in the L-bracket.
– Dispersion tube and slip coupling must be fully engaged on header
stub for O-rings to provide a seal.
– High end of L-bracket can be fastened tight to duct or air handler.
– Fastener on low end of L-bracket must be long enough to compensate
for pitch. Use a nut on both sides of L-bracket and duct or air handler
for stability.
• 2" (DN50) dispersion tubes
– Fasten bracket to top of duct and use hose cuffs to compensate for
header pitch.
– Before securing hose cuffs with hose clamps on dispersion tube
and header stub, verify that dispersion tube orifi ces are directed
perpendicular to airfl ow.
Note:
See Page 46 for steam supply and condensate
drain line connection instructions.
8. Verify that all fasteners are secure:
• L-bracket to duct
• Dispersion tubes to L-bracket
• Hose clamps on 2" (DN50) tubes
• Header support bracket fastener
9. Secure and seal the header escutcheon plate around the header.
mc_060210_1050
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
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Page 50
INSTALLATION
Dispersion: Rapid-sorb
STEAM SUPPLY CONNECTIONS TO RAPID-SORB HEADER
Connect the steam supply interconnecting piping from the humidifi er to the
Rapid-sorb. The steam supply piping requires a minimum of 1/8"/ft (1%) pitch
toward the header.
If multiple humidifi ers are supplying one Rapid-sorb, a multiple steam supply
connector is needed. Typically, the multiple steam supply connector attaches to
the Rapid-sorb header supply end with hose cuff and clamps:
1. Route the necessary number of steam supplies from the humidifier tanks to
the steam supply connector.
2. Position the steam supply connector to accept the steam supplies while
maintaining the necessary pitch.
3. Make sure the hose clamps on the steam supply connector and header are
tight.
CONDENSATE DRAIN CONNECTIONS TO RAPID-SORB HEADER
Piping must be minimum 3/4" I.D. (DN20) and rated for 212 °F (100 °C)
minimum continuous operating temperature.
The condensate drain line must be piped as shown in Figures 42-1 and 44-1.
Provide a 6" (152 mm) drop prior to a 5" (127 mm) water seal to:
• Ensure drainage of condensate from the header
• Keep steam from blowing out of the drain line
After the water seal, run the drain line to an open drain with a 1" (25 mm)
vertical air gap.
• Cut the drain line at a 45° angle on the end above the drain to permit a
direct stream of water into the drain pipe while maintaining a 1" (25 mm)
air gap.
FIGURE 46-1: ULTRA-SORB WITH THE
HIGH-EFFICIENCY TUBE OPTION
High-efficiency Tube option
Dispersion assemblies with the High-effi ciency
Tube option are designed to produce
signifi cantly less dispersion-generated
condensate and airstream heat gain, which
reduces wasted energy by up to 85%.
These improvements are accomplished by
reducing the thermal conductivity of the tubes
with 1/8" of polyvinylidene fl uoride (PVDF)
insulating material on the outside of the tubes.
These assemblies require careful unpacking,
installation, and handling. If your dispersion
assembly has the High-effi ciency Tube option,
be sure to read this section carefully.
• Locate air gap only in spaces with adequate temperature and air movement
to absorb fl ash steam, or condensing on nearby surfaces may occur.
All drain lines must be installed and sized according to governing codes.
ULTRA-SORB
For Ultra-sorb steam dispersion panel instructions, see the installation,
operation, and maintenance manual shipped with the Ultra-sorb.
See also Figure 46-1.
mc_060210_1300-NA
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
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Page 51
Start-up procedure
After the system is installed and connected properly:
1. Verify that the STS humidifier, controls, piping, electrical connections, steam
supply, and dis per sion unit(s) are installed according to the following:
• Installation instructions in this manual
• Vapor-logic In stal la tion and Op er a tion Man u al
• Ladder style wiring diagram (inside control cabinet)
• External connections wiring diagram (inside control cabinet)
• All governing codes
2. Verify that electrical connections in the control cabinet and at the
humidifier are secure before applying power.
3. Verify that the humidifier is mounted level and securely supported before
filling with water. See operating weights in Table 6-1.
OPERATION
WARNING
Electric shock hazard
Only qualifi ed electrical personnel
should perform start-up procedure.
Contact with energized circuits can
cause property damage, severe
personal injury or death as a result of
electrical shock or fi re.
Make sure control cabinet door is in
place and secure before turning on
electrical power.
The Vapor-logic version 5 In stal la tion and Op er a tion Man u al is a comprehensive
operation manual. Refer to it for information
regarding the following features:
4. Verify that the humidifier is level from front to back and side to side after it
is full of water.
5. Read the “Operation” section of the Vapor-logic Installation and Operation Manual.
Note: During start-up, do not leave the humidifi er unattended.
6. Perform all applicable “Start-up checklist” items. See Page 48.
7. Monitor humidifier operation through multiple fill cycles. The humidifier
operating status appears on the keypad/display.
8. On tap/softened water units, water skims from the humidifier after every fill
cycle. Adjust the amount of skim by increasing or de creas ing the skim time
(see the Vapor-logic Installation and Operation Manual).
At start-up, DriSteem recommends initially running the humidifier with the
factory default setting for skim time. See “Maintenance,” beginning on
Page 49.
mc_060210_1400-STS
• Keypad/display setup and menu information
• Control input signals and functions
• Drain, fl ush, and skim features
• Safety features
• Alarm screens and fault messages
The manual was shipped with your
humidifi er and is available at our Web site:
www.dristeem.com
mc_052410_1340
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
47
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OPERATION
Start-up checklist
If an item in the Start-up checklist below does not apply to your system, skip to
the next item and continue the process.
☐ Read this manual and all other information that was provided with your
humidifi er.
☐ Verify that all fi eld wiring is done according to the instructions in this
manual and in the humidifi er wiring diagram.
☐ Confi rm that the input signal is consistent with the Vapor-logic controller's
expected input signal. Input signals are listed in the Vapor-logic Setup
menu. See “Installation Step 2: Setup” in the Vapor-logic Installation and Operation Manual.
☐ Confi rm that proper grounding and an approved earth ground are
provided.
☐ Confi rm that the keypad/display is mounted with its modular cable routed
away from high-voltage circuits and connected to the Display connector on
the Vapor-logic board.
☐ Turn on the water supply, and confi rm that the drain valve is closed.
☐ Turn on power to the humidifi er, and confi rm the Main menu is displayed
on the keypad/display. The display may take several seconds to appear as
the controller powers up.
☐ Confi rm in the Main Menu that the mode is “Auto” and that tank status is
“Filling.”
☐ When “Filling” appears in main menu, confi rm that the tank is fi lling with
water.
☐ In the Status screen, confi rm that the Duct Airfl ow Switch is closed.
☐ In the Status screen, confi rm that the high limit humidistat input is closed or
the high limit transmitter is connected.
☐ With suffi cient water in the tank, the airfl ow switch closed, the high limit
closed, the safety interlock closed, and the humidifi er getting a call for
humidity, verify that the steam valve is activated.
☐ If you experience diffi culties, have the keypad/display information
available along with the serial number and humidifi er Model, and call
DriSteem Technical Support at 800-328-4447.
mc_060210_1355-STS
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
48
Page 53
Water quality
The best way to determine how often your humidifi er needs maintenance is to
remove the tank cover and inspect it for mineral deposits after three months
of duty. Hours of operation and duty cycle will determine your maintenance
schedule, as will water quality.
WATER QUALITY AND MAINTENANCE
Maintenance requirements vary with water quality, because tap and softened
water carry a variety of minerals and other materials in a mix that varies from
location to location. Very hard (high mineral content) water requires more
frequent cleaning and drain/fl ush cycles than water with low mineral content.
Softened water signifi cantly reduces mineral accumulation inside the humidifi er.
Note: Solids, like silica, are not removed in the softening process.
SKIM DURATION
Skim duration determines the quantity of water skimmed with each fi ll cycle
and is fi eld adjustable using the Vapor-logic keypad/display.
MAINTENANCE
WARNING
Hot surface and hot water hazard
Do not touch the tank or drain piping
until the unit has had suffi cient time to
cool, or serious injury can occur.
Opening the drain valve when the
tank is hot can discharge water with a
temperature up to 212 °F (100 °C) into
the plumbing system. This can cause
damage to the plumbing system if the
humidifi er is not properly connected
to a water tempering device such as a
DriSteem Drane-kooler
mc_060110_1640
™
.
Skimming reduces the need for frequent humidifi er cleaning. Each time the
tank refi lls, it fi lls to a level just above the lip of the skim/overfl ow fi tting. A
portion of the fi ll water fl ows out of the skim/overfl ow fi tting to the drain, which
fl ushes minerals left by the previous evaporating cycle and skims away surface
residue.
Both humidifi er cleaning and heated water fl owing to the drain are operational
costs. DriSteem recommends that the user observe and adjust the skim duration
to achieve a balance between reducing mineral buildup and conserving
heated water.
mc_060210_1430
Humidifier De-scaling Solution
Scale buildup on humidifi er heat exchangers
acts as an insulator, reducing humidifi er
performance while increasing energy costs.
To keep humidifi ers operating as effi ciently
as possible, remove scale with DriSteem's
Humidifi er De-scaling Solution, available for
purchase from your DriSteem representative or
distributor.
The De-scaling Solution cleans without risk
of corroding humidifi er tanks or welds. The
De-scaling Solution also cleans surfaces
unreachable by hand scraping.
DriSteem's Humidifi er De-scaling Solution is the
only approved cleaner/de-scaler for use with
DriSteem humidifi ers. Use of other cleaners/
de-scalers may void your DriSteem warranty.
mc_021908_1410-heatx
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
49
Page 54
MAINTENANCE
Tap/softened water
COOL DOWN HUMIDIFIER
Before performing any maintenance, allow the tank to cool down.
Note: Fresh make-up water is used to speed up cooling. Do not close the
manual water supply before cooling down the humidifi er; otherwise the
tank could stay hot for several hours.
• Insulated and uninsulated tanks will have hot surfaces.
• Close the manual shut-off valve on the inlet steam supply.
• Models with a standard drain valve and Vapor-logic controller:
– For drain valves without the manual open lever, use the keypad to
perform the cool down process. Refer to the Vapor-logic Installation and
Operation Manual.
– Select Manual Drain in the control modes screen.
– Allow approximately half the water to drain out of the tank.
– Select Auto in the control modes screen; the fi ll valve opens and the
humidifi er cools down.
– When the fi ll valve closes, select Manual Drain in the control modes
screen and allow the tank to drain dry. The humidifi er should be cool
enough to work on.
CAUTION
Hot discharge water
Discharge water can be as hot as
212 °F (100 °C) and can damage the
drain plumbing.
To prevent such damage from
humidifi ers without water tempering,
allow the tank to cool before draining.
Humidifi ers equipped with a water
tempering device such as a DriSteem
Drane-kooler need fresh make-up
water in order to function properly.
Make sure the water supply to the
water tempering device remains open
during draining.
Excessive supply water pressure
Supply water pressure greater than 80
psi (550 kPa) can cause the humidifi er
to overfl ow.
mc_030910_1440
Troubleshooting
The Vapor-logic Installation and Operation
Manual, which was shipped with your
humidifi er, is a comprehensive operation
manual. Refer to it for troubleshooting
information.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
50
Page 55
Tap/softened water
INSPECTION AND MAINTENANCE
1. Annually (also recommended when maintenance is performed)
• All safety devices in the control circuit should be cycled on and off to
verify they are functioning. These include:
– High limit switch
– Airfl ow proving switch
– Low water level probe. Pull out probe plug; fi ll valve should energize.
• Inspect tank and gaskets for leaks.
2. Seasonally (or as required, depending on water quality)
• Cleaning the tank
– Remove cleanout plate and dispose any loose scale that has
collected in the bottom of the tank. This should be done before the
scale buildup reaches the bottom of the heat exchanger.
– Inspect the area inside the tank in front of the drain valve fi tting, and
thoroughly clean all scale and mineral buildup from that area.
• Cleaning the probes
– Disconnect the probe plug and cable assembly (located on top of the
tank), and unscrew the probe rod assembly from the humidifi er probe
housing using the probe tool (see Figure 51-1).
– Inspect the probe housing and clean, ensuring that all housing
passageways are clear. To detach the housing from the tank, remove
the four bolts that attach it to the tank. Then lift the housing up out of
the tank.
– The scale should fl ake off easily from the probe assembly rods.
– The bottom 3/8" (10 mm) is the sensing portion of each probe rod;
it should be brushed clean with a wire brush, abrasive pad, or steel
wool.
– Inspect the composite plastic probe rod assembly for any signs
of cracking, roughness, or deterioration. If found, replace probe
assembly.
– Reassemble the probe rod assembly, and torque as indicated in
Figure 51-1.
MAINTENANCE
WARNING
Shutdown procedure
To prevent serious injury, follow this
shutdown procedure before performing
service or maintenance procedures on
this humidifi er (after the tank has cooled
down and drained):
1. Use Vapor-logic keypad/display to
change control mode to Standby.
2. Place all power disconnects in OFF
position and lock in OFF position.
3. Close the fi eld-installed manual
water supply shut-off valve.
4. Close the manual shut-off valve on
the inlet steam supply.
FIGURE 51-1: PROBE TOOL
Probe tool
OM-7395X
Remove and install probe assembly with
supplied probe tool. Attach a 3/8" square
drive to the probe tool.
When installing, torque probe assembly to 120
in-lbs (10 ft-lbs; 13.6 N-m). Probe tools can be
ordered from your DriSteem representative (Part
no. 185101).
mc_060310_0735
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
51
Page 56
MAINTENANCE
Tap/softened water
• Cleaning the skim overfl ow port
– Water should drain from the skimmer drain pipe after each fi ll cycle.
This should be verifi ed visually by a weekly inspection.
– Loosen deposits in and around the skimmer overfl ow port with a long
tool such as a screwdriver.
– Water should drain from the skimmer drain pipe after each fi ll cycle.
This should be verifi ed visually by a weekly inspection.
– Loosen deposits in and around the skimmer/overfl ow port with a
long tool such as a screwdriver.
– If fl ow through the water seal/P-trap is diminished due to mineral
accumulation:
- Remove the water seal piping from the hu mid i fi er and fl ush out.
- Replace the water seal with new piping if the minerals have
hardened in the water seal.
- Install a union at the base of the water seal to ease removal if
water quality causes the water seal to become clogged often with
scale.
When the seasonal maintenance requirements are complete:
• Re-install the cleanout plate, and torque the nuts to 25 to 35 in-lbs (2.8 to
4.0 N-m).
• Verify that the probe rod holder is secure and that the probe plug and cable
assembly are plugged into the probe rod holder.
• Replace and secure all covers.
• Verify that the drain valve assembly is in the closed position.
• Turn on the water supply.
• Turn on the electrical power.
• Do not leave humidifi er unattended. Allow the humidifi er to cycle through
multiple fi ll cycles and verify that the humidifi er cover, cleanout plate, and
probe holder gasket are not leaking.
3. Off-season maintenance
• Perform complete inspection and cleaning of the following:
– Heat exchanger
– Probe rods
– Skimmer port and water seal
– Humidifi er tank
• After the humidifi cation season, DriSteem recommends a complete
inspection and cleaning of the heat exchanger, skimmer, and
water chamber. After cleaning, the unit should remain empty until
humidifi cation is required.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
52
Page 57
RO/DI water option
Regularly verify that water processing equipment is operating correctly. The
presence of chlorides in improperly processed RO/DI water eventually causes
pitting and failure of the heat exchanger, tank, and components. Your DriSteem
warranty does not cover damage caused by chloride corrosion.
STS humidifi ers with the RO/DI water option do not require cleaning, but
regular inspections are advised. There are no skimming, drain, or fl ush cycles.
COOL DOWN HUMIDIFIER
Before performing any maintenance, allow the tank to cool down.
Note: Fresh make-up water is used to speed up cooling. Do not close the
manual water supply before cooling down the humidifi er; otherwise the
tank could stay hot for several hours.
• Insulated and uninsulated tanks will have hot surfaces.
• Close the manual shut-off valve on the inlet steam supply.
MAINTENANCE
WARNING
Shutdown procedure
To prevent serious injury, follow this
shutdown procedure before performing
service or maintenance procedures on
this humidifi er (after the tank has cooled
down and drained):
1. Use Vapor-logic keypad/display to
change control mode to Standby.
2. Place all power disconnects in OFF
position and lock in OFF position.
3. Close the fi eld-installed manual
water supply shut-off valve.
4. Close the manual shut-off valve on
the inlet steam supply.
• Models with a standard drain valve:
– Manually open the drain valve.
The fl oat valve opens.
– Let the fi ll water run until the tank is cooled; then shut off the fi eld-
installed manual supply water shut-off valve.
– Let the tank drain; then manually close the drain valve.
• Models with end-of-season drain option:
– Use the keypad to perform the cool down process. Refer to the
Vapor-logic Installation and Operation Manual.
– Select Manual Drain in the control modes screen.
– Allow approximately half the water to drain out of the tank.
– Select Auto in the control modes screen; the fi ll valve opens and the
humidifi er cools down.
– When the fi ll valve closes, select Manual Drain in the control modes
screen and allow the tank to drain completely dry. The humidifi er should
be cool enough to work on.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
53
Page 58
MAINTENANCE
RO/DI water option
INSPECTION AND MAINTENANCE
1. Annually (also recommended when maintenance is performed)
• All safety devices in the control circuit should be cycled on and off to
verify they are functioning. These include:
– High limit switch
– Airfl ow proving switch
• Inspect tank and gaskets for leaks.
• Verify that the fl oat valve is closing off. If the fl oat valve will not shut off,
there may be particulate on the valve seat, or the stopper may be worn
and need replacing.
As long as mineral-free water is used in the humidifi er, no cleaning or
fl ushing should be necessary.
2. Off-season maintenance
• Perform a complete inspection of the following:
– Heat exchanger
– Float valve
– Humidifi er tank and gaskets
• After inspection, the humidifi er should remain empty until humidifi cation
is required.
• After the humidifi cation season, DriSteem recommends a complete
inspection and cleaning of the heat exchanger, skimmer, and
water chamber. After cleaning, the unit should remain empty until
humidifi cation is required.
On units with Tefl on coated heat exchangers, do not use a sharp object
when cleaning. Cuts or scratches on the heat exchanger will impair
its ability to shed scale during operation and could cause the Tefl on to
separate from the metal surface.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
54
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Outdoor Enclosure
Access to the humidifi er side cleanout plate is through the Outdoor Enclosure
electrical service door.
MAINTENANCE
WARNING
• Clean vent screens annually.
• Check for proper operation of strip heaters and ventilation fans annually.
• Refer to instructions for complete humidifi er maintenance, beginning on
Page 49.
1. Always switch the keypad control
mode to Standby.
2. Place all power disconnects in OFF
position and lock in OFF position.
3. Close the fi eld-installed manual
supply water shut-off valve.
4. Close the manual shut-off valve on
the inlet steam supply.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
55
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REPLACEMENT PARTS
Humidifi er tank
FIGURE 56-1: TANK REPLACEMENT PARTS
OM-946
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
56
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Humidifi er tank
Table 57-1:
Tank replacement parts
No.DescriptionPart no.
1Tank, STSConsult factory
Cover, STS-25165341-001
Cover, STS-50165341-002
2
Cover, STS-100165341-003
Cover, STS-200/400/800165341-004
Cover gasket, STS-25160692-001
Cover gasket, STS-50160692-002
3
Cover gasket, STS-100160692-003
Cover gasket, STS-200/400/800160692-004
4Heat exchanger, STSConsult factory
Cleanout plate, STS-25165481-001
5
Cleanout plate, STS-50/100165481-002
Cleanout plate, STS-200/400/800165481-003
Cleanout plate gasket, STS-25308015-001
6
Cleanout plate gasket, STS-50/100308015-002
Cleanout plate gasket, STS-800505340
7Fill assemblyConsult factory
Float fi ll assembly, STS-25/50/100505315
8*
Float fi ll assembly, STS-200/400505305
Float fi ll assembly, STS-800505340
9Drain assemblyConsult factory
10Temperature sensor assembly405760
Probe assembly, STS-25/50/100/200/400406303-108
11
Probe assembly, STS-800406303-109
12Probe gasket309350-004
13*Probe plate120370-020
14Probe weld165301
15Probe plate/weld gasket308416-001
16Heat exchanger gasket, STS308220
17Heat exchanger mounting plate164581-001
18Junction box407134-005/006
19Condensate return plug250192-075
20Probe plug406050-004
Components may be in different location or orientation than shown in drawing on previous page.
* STS with RO/DI water option only
REPLACEMENT PARTS
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
57
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REPLACEMENT PARTS
Control cabinet
FIGURE 58-1: CONTROL CABINET REPLACEMENT PARTS
15
12
10
9
Note: Components may be in different location or orientation than shown in drawing.
14312
565
7
8
11
Table 58-1:
Control cabinet replacement parts*
No.DescriptionPart no.
1Control cabinet, 12 x 12407100-003
2Subpanel, STS165720-002
3Control board, Vapor-logic183504-014
4Transformer, 120V to 24V408965-001
5Terminal block408252-001
6Ground terminal408252-010
7Terminal jumper408252-009
8Relay, 24V 3PDT, Finder407900-017
9DIN-rail end cap408252-006
10 Terminal spacer408252-005
11 DIN-rail, 6.5" (165 mm)167765-006
12 Ground lug409250-003
13 P-E switch408100
14 Interlock switch408470
15 Interlock switch bracket165614
16 Vapor-logickeypad/display with back408495-010
17 Vapor-logickeypad cable, 5' (1.5 m)408490-009
* Specify humidifi er model and serial numbers when ordering.
16
13
12
4
OM-7646
17
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
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Outdoor Enclosure
FIGURE 59-1: OUTDOOR ENCLOSURE REPLACEMENT PARTS
5
6
7
REPLACEMENT PARTS
1
2
4
OM-953
4
3
Table 59-1:
Outdoor Enclosure replacement parts
Number in drawingDescriptionPart number
1500W strip heater405800-052
21100W strip heater405800-053
3Cooling fan405800-068
4Gasket, door or roof308005-010*
5Stat, high limit405800-065
6Stat, heater405800-066
7Stat, fan405800-067
* Specify quantity in feet
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
59
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W
ARRANTY
Expect quality from the industry leader
For more than 45 years, DriSteem has
been leading the industry with creative and
reliable humidifi cation solutions. Our focus
on quality is evident in the construction of the
STS, which features cleanable, stainless steel
construction. DriSteem also leads the industry
with a Two-year Limited Warranty and optional
extended warranty.
For more information
www.dristeem.com
sales@dristeem.com
For the most recent product information
visit our Web site: www.dristeem.com
DRI-STEEM Corporation
a subsidiary of Research Products Corporation
DriSteem is an ISO 9001:2008 certifi ed company
U.S. Headquarters:
14949 Technology Drive
Eden Prairie, MN 55344
800-328-4447 or 952-949-2415
952-229-3200 (fax)
European offi ce:
Marc Briers
Grote Hellekensstraat 54 b
B-3520 Zonhoven
Belgium
+3211823595 (voice)
+3211817948 (fax)
E-mail: marc.briers@dristeem.com
Continuous product improvement is a policy of
DriSteem Corporation; therefore, product
features and specifi cations are subject to
change without notice.
DriSteem, STS, DriCalc, Rapid-sorb, and
Vapor-logic are registered trademarks of
Research Products Corporation and are fi led
for trademark registration in Canada and the
European community.
Two-year Limited Warranty
DRI-STEEM Corporation (“DriSteem”) warrants to the original user that its products will be free from
defects in materials and workmanship for a period of two (2) years after installation or twentyseven (27) months from the date DriSteem ships such product, whichever date is the earlier.
If any DriSteem product is found to be defective in material or workmanship during the applicable
warranty period, DriSteem’s entire liability, and the purchaser’s sole and exclusive remedy,
shall be the repair or replacement of the defective product, or the refund of the purchase price,
at DriSteem’s election. DriSteem shall not be liable for any costs or expenses, whether direct
or indirect, associated with the installation, removal or reinstallation of any defective product.
Excluded from the Limited Warranty are all consumable and wear and tear items such as cylinders,
membranes, fi lters, or media replacements. These items are subject to usual wear and tear during
usage.
DriSteem’s Limited Warranty shall not be effective or actionable unless there is compliance with
all installation and operating instructions furnished by DriSteem, or if the products have been
modifi ed or altered without the written consent of DriSteem, or if such products have been subject
to accident, misuse, mishandling, tampering, negligence or improper maintenance. Any warranty
claim must be submitted to DriSteem in writing within the stated warranty period. Defective parts
may be required to be returned to DriSteem.
DriSteem’s Limited Warranty is made in lieu of, and DriSteem disclaims all other warranties,
whether express or implied, including but not limited to any IMPLIED WARRANTY OF
MERCHANTABILITY, ANY IMPLIED WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE, any
implied warranty arising out of a course of dealing or of performance, custom or usage of trade.
DriSteem SHALL NOT, UNDER ANY CIRCUMSTANCES BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, LOSS OF PROFITS, REVENUE OR BUSINESS) OR DAMAGE OR INJURY TO PERSONS OR
PROPERTY IN ANY WAY RELATED TO THE MANUFACTURE OR THE USE OF ITS PRODUCTS. The
exclusion applies regardless of whether such damages are sought based on breach of warranty,
breach of contract, negligence, strict liability in tort, or any other legal theory, even if DriSteem has
notice of the possibility of such damages.
By purchasing DriSteem’s products, the purchaser agrees to the terms and conditions of this Limited
Warranty.
Extended warranty
The original user may extend the term of the DriSteem Limited Warranty for a limited number of
months past the initial applicable warranty period and term provided in the fi rst paragraph of this
Limited Warranty. All the terms and conditions of the Limited Warranty during the initial applicable
warranty period and term shall apply during any extended term. An extended warranty term of
an additional twelve (12) months or twenty four (24) months of coverage may be purchased. The
extended warranty term may be purchased until eighteen (18) months after the product is shipped,
after which time no extended warranties are available. When a Dristeem humidifi er is purchased
with a DriSteem RO system, an extended twenty-four (24) month coverage is included.
Any extension of the Limited Warranty under this program must be in writing, signed by DriSteem,
and paid for in full by the purchaser.
Drane-kooler is a trademark of DriSteem
Corporation.
Product and corporate names used in this
document may be trademarks or registered
trademarks. They are used for explanation only
without intent to infringe.