DriSteem STS Installation Manual
READ AND SAVE THESE INSTRUCTIONS
®
STS
Steam-to-Steam Humidifier
Installation, Operation,
and Maintenance Manual
WARNINGS AND CAUTIONS
Warnings and cautions
WARNING
Indicates a hazardous situation that could result in death or
serious injury if instructions are not followed.
CAUTION
Indicates a hazardous situation that could result in damage to or
destruction of property if instructions are not followed.
WARNING
Attention installer
Read this manual before installing, and leave this manual with product owner. This product must be installed by qualified
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 fire.
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
Hot surfaces and hot water
This steam humidification 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
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 humidification system. Failure to disconnect electrical power could result in fire, 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 fire. 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
humidifier, after the tank has cooled down and drained.
1. Follow the “Cool down humidifier” instructions on Page 50 (tap/softened water STS) or Page 53
(STS with RO/DI water option) to put the humidifier 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 field-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.
Humidifiers 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 humidifier 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 humidifier to overflow.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
iii
Table of contents
1
WARNINGS AND CAUTIONS ...................................................ii
OVERVIEW.................................................................2
Product overview ........................................2
Tap/softened water ....................................2
RO/DI water option ...................................2
Water type conversion .................................2
Dimensions ............................................4
Capacities, electrical specifications, and weights ..................6
INSTALLATION ..............................................................7
Selecting a location ......................................7
Mounting methods .......................................8
Mounting the humidifier ...................................9
Support legs ........................................9
Wall brackets ........................................9
H-legs .............................................9
Trapeze hanger ......................................9
Weather cover .........................................10
Outdoor Enclosure ......................................12
Electrical specifications .................................13
Mounting ..........................................15
STS Outdoor Enclosure sequence of operation ................17
Alternate water seal and drain valve piping ..................18
Piping: ...............................................18
Drain ............................................18
Fill ...............................................20
Tap/softened water, one heat exchanger ...................22
Tap/softened water, two heat exchangers ...................23
RO/DI water option, one heat exchanger ...................24
RO/DI water option, two heat exchangers ..................25
Pressurized steam supply ...............................26
Humidification steam outlet .............................27
Wiring ..............................................28
Wiring diagram locations ..............................28
Electrical installation ..................................28
Wiring requirements ..................................28
Control wiring ......................................29
Grounding requirements ................................29
Sensor placement .......................................30
Dispersion: ............................................31
Selecting the dispersion assembly location ..................31
Interconnecting piping requirements .......................32
Drip tee installation ...................................34
Single tube and multiple tube ............................35
Rapid-sorb .........................................40
Ultra-sorb ..........................................46
Attention installer
Read this manual before installing.
Leave manual with product owner.
Where to find more information
Our web site:
The following documents are available on our
web site: www.dristeem.com
• Catalogs
– STS
– Ultra-sorb
• Installation, Operation, and Maintenance
manuals (IOM)
– Ultra-sorb Models LV and LH
– Ultra-sorb Model XV
– Vapor-logic controller (includes humidifier
operation and troubleshooting)
• DriSteem Humidification System Design
Guide (includes steam loss tables and
general humidification information)
DriCalc®:
DriCalc, our software for humidification system
sizing and selection, can be ordered at our
web site. Also in Dri-calc:
• Library of installation guides
• Dispersion and sensor placement in ducts
and air handlers
• Vertical airflows
Call us at 800-328-4447
Obtaining documents from our web site or
from DriCalc is the quickest way to view our
literature, or we will be happy to mail literature
to you.
®
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
iv
Table of contents
OPERATION ..............................................................47
Start-up procedure ......................................47
Start-up checklist ........................................48
MAINTENANCE ........................................................... 49
Water quality .........................................49
Tap/softened water ......................................50
RO/DI water option .....................................53
Outdoor enclosure ......................................55
REPLACEMENT PARTS ...................................................... 56
Humidifier tank ........................................56
Control cabinet ........................................58
Outdoor enclosure ......................................59
WARRANTY .............................................................. 60
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
1
OVERVIEW
Product overview
STS (steam-to-steam) humidifiers use pressurized boiler steam to heat clean fill
water into chemical-free steam for humidification. See Figure 3-1.
STS humidifiers 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 humidifier; therefore, water conductivity must be at least 30 µS/
cm for proper operation. A tap/softened water STS humidifier will not operate
with RO/DI water. For RO/DI water, use STS with the RO/DI water option.
RO/DI WATER OPTION
STS humidifiers with the RO/DI water option control water level with a float
valve (Figure 3-3). Float valves are compatible with RO/DI water only.
Humidifiers with the RO/DI water option are virtually maintenance free and
require little or no downtime.
WATER TYPE CONVERSION
STS tap/softened water humidifiers can be converted in the field for use with
RO/DI water, and STS RO/DI water humidifiers can be converted in the field
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 humidifier 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 humidifier service life and
minimize humidifier 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
humidifier. 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
Product overview
OVERVIEW
FIGURE 3-1: STS HUMIDIFIERS
Notes:
• Drain piping material must be suitable for 212 °F (100 °C) water.
• See the piping drawings on Pages 22 through 25.
Tap/softened water STS humidifier
Humidification steam outlet
Probe water level control
Automatic steam valve
Boiler steam
Steam trap
Condensate return
Water seal
Air gap
Open drain
Manual drain or optional
motorized drain valve
STS humidifier with the RO/DI water option
Humidification steam outlet
Float valve water level control
OM-938
Heat exchanger
FIGURE 3-2: WATER LEVEL CONTROL
FOR TAP/SOFTENED WATER HUMIDIFIER
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).
Humidifiers 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.
VLC-OM-030
Automatic steam valve
Boiler steam
Steam trap
Condensate return
Water seal
Heat exchanger
Manual drain valve
Air gap
Open drain
OM-939
FIGURE 3-3: WATER LEVEL CONTROL
FOR RO/DI-WATER OPTION HUMIDIFIER
Fill valve
Float rod
VLC-OM-026
Humidifiers using RO/DI water control water
level using a float valve. An optional low-water
cutoff switch is available as a remote water
indicator.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Float ball
3
OVERVIEW
Dimensions
FIGURE 4-1: DIMENSIONS, STS MODELS 25, 50, 100, 200, AND 400 (WITH COPPER OR STAINLESS STEEL HEAT EXCHANGERS)
Front view Side view
L
J
K
D
E
Mounting holes:
Models 25–100: 5/16" (8 mm) slot
Models 200 & 400: 1/2" (12 mm) slot
A
M
H
B
Notes:
• Tap/softened water model shown
• See dimensions in Tables 5-1 and 5-2
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
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
4
OVERVIEW
Dimensions
Table 5-1:
Dimensions, STS with copper heat exchangers
See drawings in Figures 4-1 and 4-2
Description
A Height** 19.50 495 19.50 495 19.50 495 19.50 495 29.75 756
B Width 14.75 375 14.75 375 19.25 489 30.25 768 30.25 768
C Length 23.65 600 39.65 1007 39.65 1007 55.15 1401 55.15 1401
D Bottom to supply inlet of first heat exchanger 6.63 168 6.63 168 6.63 168 6.63 168 6.63 168
E Bottom to return outlet of first heat exchanger 3.63 92 3.63 92 3.63 92 3.63 92 3.63 92
F Bottom to supply inlet of second heat exchanger — — — — — — — — 14.28 363
G Bottom to return outlet of second heat exchanger — — — — — — — — 11.24 285
H Side to heat exchanger 3.25 83 3.25 83 3.25 83 3.25 83 3.25 83
J Pressurized steam supply inlet
K Pressurized condensate return outlet
L Side to steam outlet 6.25 159 8.63 219 9.63 245 13.00 330 13.00 330
M Front to steam outlet 2.50 64 2.25 57 2.75 70 3.75 95 3.75 95
* 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.
25C 50C 100C 400C 800C
inches mm inches mm inches mm inches mm inches mm
3/4" p ip e
thread
3/4" p ip e
thread
DN20
DN20
1¼" pipe
thread
3/4" p ip e
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** 19.50 495 19.50 495 19.50 495 19.50 495 19.50 495 29.75 756
B Width 14.75 375 14.75 375 19.25 489 30.25 768 30.25 768 30.25 768
C Length 23.65 600 39.65 1007 39.65 1007 55.15 1401 55.15 1401 55.15 1401
Bottom to supply inlet of first heat
D
exchanger
Bottom to return outlet of first 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 exchanger 3.25 83 3.25 83 3.25 83 3.25 83 3.25 83 3.25 83
J Pressurized steam supply inlet
K Pressurized condensate return outlet
L Side to steam outlet 6.25 159 8.63 219 9.63 245 13.00 330 13.00 330 13.00 330
M Front to steam outlet 2.50 64 2.25 57 2.75 70 3.75 95 3.75 95 3.75 95
* 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
25S 50S 100S 200S 400SNC 800SNC
inches mm inches mm inches mm inches mm inches mm inches mm
6.85 174 6.85 174 6.85 174 6.85 174 6.85 174 6.85 174
3.35 85 3.35 85 3.35 85 3.35 85 3.35 85 3.35 85
— — — — — — — — — — 14.5 368
— — — — — — — — — — 11.0 279
3/4" pi pe
thread
3/4" pi pe
thread
DN20
DN20
1" pipe
thread
3/4" pi pe
thread
DN25
DN20
1" pipe
thread
3/4" pi pe
thread
STS model*
DN25
DN20
1½" pipe
thread
3/4" pi pe
thread
DN40
DN20
1½" pipe
thread
3/4" pi pe
thread
DN40
DN20
1½" pipe
thread
3/4" pi pe
thread
DN40
DN20
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
5
OVERVIEW
Capacities, electrical specifications, 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
25C 20 9 70 32 100 45 120 54
50C 50 23 150 68 200 91 240 109
100C 100 45 300 136 400 181 480 218
400C 300 136 580 263 720 327 790 358
800C 650 295 1275 578 1500 680 1600 726
Table 6-2:
STS humidifier models and capacities with stainless steel heat exchangers
STS models
25S 10 5 25 11 30 14 35 16
50S 30 14 55 25 75 34 80 36
100S 60 27 110 50 140 64 150 68
200S 150 68 290 132 360 163 390 177
400SNC 170 77 392 178 552 250 637 289
800SNC 212 96 825 374 1095 497 1223 555
5 psi (34 kPa) 10 psi (69 kPa) 13 psi (90 kPa) 15 psi (103 kPa)
lbs/hr kg/h lbs/hr kg/h lbs/hr kg/h lbs/hr kg/h
Steam pressure at connection to STS steam valve (valve provided by DriSteem)
5 psi (34 kPa) 10 psi (69 kPa) 13 psi (90 kPa) 15 psi (103 kPa)
lbs/hr kg/h lbs/hr kg/h lbs/hr kg/h lbs/hr kg/h
For use with tap/softened or RO/DI water:
• STS models ending in C (copper heat
exchangers with a nickel coating)
• STS models ending in S (stainless steel heat
exchangers with a Teflon coating)
For use with RO/DI water option only:
STS models ending in SNC (stainless steel heat
exchangers with no coating)
Table 6-3:
STS humidifier weights
STS model
25 95 43 175 79
50 125 57 336 152
100 139 63 350 159
200 245 111 850 386
400 320 145 950 431
800 410 186 1450 658
* Operating weight does not include weight of interconnecting piping provided by installer.
Shipping weight Operating weight*
lbs kg lbs kg
Table 6-4:
STS humidifier electrical specifications
North America 120 V single phase max 3 amps
Europe 230 V single phase max 3 amps
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
6
Selecting a location
When selecting the location of the humidifier, consider the following:
• Maximum ambient temperature for control cabinet is 104 °F (40 °C).
• Noises inherent to operation such as STS water fill cycles
• Easy access for maintenance
• Critical service and maintenance clearances around humidifier — primarily
top, left side, and front (see Figure 7-1).
• Convenient location to dispersion system for routing of steam hose or tubing
• Electrical connections — power, control, and safety circuits
• Steam supply piping connections — inlet steam piping, condensate piping,
and optional equipment (see Figure 26-1)
• Plumbing connections — supply water, drain piping, and condensate return
piping
• Water seal requirements
INSTALLATION
• 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)*
Rear: 6" (152 mm)
DC-1452
Right
side:
6" (152 mm)
Bottom:
24" (610 mm)
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
7
INSTALLATION
Mounting methods
FIGURE 8-1: SUPPORT LEGS, STS MODELS 25, 50, AND 100 ONLY
Tap/softened water model shown
Optional set of four legs and hardware
OM-933
FIGURE 8-3: WALL BRACKETS, STS MODELS 25, 50, AND 100 ONLY
DC-1454
DriSteem optional wall
brackets (two required)
A
Tap/softened water model shown
STS model
25 and 50 15.5 394 24 610
B
100 21 533 30 762
A B
in. mm in. mm
FIGURE 8-2: TRAPEZE HANGER, STS
MODELS 25, 50, AND 100 ONLY
See Note 1
Provide 18"
(457 mm)
minimum
clearance
above cover
1¼" (DN32)
minimum
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
humidifier.
4. Humidifier drain to appropriate building
waste. Do not drain humidifier 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
See Note 5
See Note 2
See Note 3
See Note 4
25%
larger than
humidifier
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.
OM-947
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
8
Mounting the humidifier
INSTALLATION
The STS humidifier 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 filled 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 humidifier. Position the wall brackets so they
are flush with the front and back flanges 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
flush with front and back flanges 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 humidifier’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 hanger standard —
H-legs — standard
Support legs optional —
Wall brackets optional —
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 floor,
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 floor, 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 humidifier, field-installed piping,
and (if mounted on the humidifier) 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
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
Hinged door
B
Table 10-1:
Weather cover weights
Weather cover size lbs kg
STS 25 to 100 425 193
STS 200 to 800 550 250
A
OM-7465
Table 10-2:
Weather cover dimensions
Letter Description
A Height 62 1575 66 1676
B Length 43.5 1105 53 1346
C Width 62 1575 78.25 1988
D Distance from bottom 22 559 22 559
STS 25 to 100 STS 200 to 800
inches mm inches mm
D
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
10
Weather cover
The optional STS weather cover is water-resistant and designed to protect an
STS humidifier 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 certified 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 humidifier. Refer
to the installation section of this manual for all electrical, supply water, and
drain connection requirements.
INSTALLATION ISSUES SPECIFIC TO WEATHER COVER APPLICATIONS
• Installation must comply with all governing codes.
• The bottom of the weather cover is open to accommodate piping and
electrical connections.
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
INSTALLATION
Outdoor Enclosure
FIGURE 12-1: OUTDOOR ENCLOSURE WITH STANDARD OR OPTIONAL STEAM OUTLET, ELEVATION VIEW
Standard steam outlet
Ventilation fans
STS humidifier
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 distribution configurations. The standard configuration has a steam outlet on the right side of the
Outdoor Enclosure for connecting to steam dispersion unit piping. The optional internal steam distribution configuration 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 enclosure 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 humidifier.
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 humidifier to reduce pressure drop.
6. See the dimensions in Table 13-1.
K
Optional steam outlet
A
6.5"
DC-1476
Pipe chase
G
Table 12-1:
Outdoor Enclosure connection sizes
Description
Water makeup
(fill)
Drain 3/4” (DN20) 1” (DN25)
Condensate
return
Steam outlet See Table 27-1.
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
12
25 – 100 200 – 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
lbs kg lbs kg
25 600 272 680 308
50 625 284 840 381
100 640 290 860 390
200 1050 476 1650 748
400 1125 510 1750 794
800 1225 556 2250 1021
* Includes humidifier
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 floor
D
H
Enclosure drain
Standard steam outlet (exits enclosure here)
STS humidifier
B
DC-1478
Table 13-1:
Outdoor Enclosure dimensions*
STS model
Item Description
A Enclosure height 56.00 1422 66.00 1676
B Enclosure width 36.00 914 46.00 1168
C
Pipe chase position
D 2.00 57 3.50 89
E
Pipe chase size
F 8.00 203 10.00 254
G
H 18.63 473 22.00 559
Steam pipe position
J 14.50 368 20.50 521
K 12.25 311 11.00 279
L Enclosure length 60.00 1524 78.00 1981
* See drawings in Figures 12-1 and 13-1.
25–100 200–800
inches mm inches mm
4.50 114 4.50 114
20.00 508 32.00 312
6.00 152 8.50 216
F
Valve section heater
Intake ventilation fan
Control panel
Control panel heater
Electrical and cleanout access door
Intake ventilation fan
Table 13-2:
STS Outdoor Enclosure electrical
specifications
Outdoor
Enclosure
without
heater
package
Outdoor
Enclosure
with heater
package
ELECTRICAL SPECIFICATIONS
Voltage Current
120 Vac,
50/60 Hz
120 Vac,
50/60 Hz
3.5 A 10 A
13.5 A 20 A
Maximum
disconnect
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
13
INSTALLATION
Outdoor Enclosure
FIGURE 14-1: OUTDOOR ENCLOSURE INSTALLATION DETAIL
Normally closed fill
valve (by factory)
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 fill line and freeze if there is a loss
of power, DriSteem recommends field installing additional valves upstream of the fill 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 fill line to prevent freezing.
2. Ensure that water lines are protected from freezing conditions.
• Install heat tracing and insulation on fill 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 fill line to cut power to the STS and safety valves to stop fill water to the STS and drain the fill 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 field 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 fill and drain piping, these drains may be tied together. Locate 1" air gap only in spaces with adequate
temperature and air movement to absorb flash steam; otherwise, condensation may form on nearby surfaces. Refer to governing codes for drain
pipe size and maximum discharge water temperature.
Humidifier
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
humidifier
STS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
14
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 floor
D
H
Enclosure drain
Standard steam outlet (exits enclosure here)
STS humidifier
MOUNTING
B
DC-1478
F
Intake ventilation fan
Control panel
Control panel heater
Intake ventilation 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 flammable vapors and liquids
in open containers in vicinity of Outdoor Enclosure is hazardous.
Valve section heater
Electrical and cleanout access
door
Important note about STS Outdoor
Enclosure installation
• Install a riser trap in the branch line leading
to the humidifier.
• 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 humidifier 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
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
sufficient 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 configurations:
– Standard configuration is a steam outlet on one side of enclosure for
connecting to steam dispersion unit piping.
– Optional internal configuration 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 fill 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
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