DriSteem GTS-100 User manual

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Following installation of this steam-generating humidifier, the installer shall instruct the user in the operation of the steam-generating
humidifier and the safety devices. The installer shall give at least this manual and the GTS Humidifier User Manual to the user.
Installation and Operation Manual
Gas-to-Steam Humidifier
GTS®

ii DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
Table of contents
The Vapor-logic5 Installation and Operation
Manual is a comprehensive manual. Refer to
it for:
• Setup and menu information
• Input signals and functions
• Alarms and messages
• Firmware updates
• Troubleshooting
• Safety features
• Options
The manual was shipped with your
humidifier. It is also available on our website:
www.dristeem.com
Before you begin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Safeguards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Product overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Finding a location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Clearance recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Outdoor enclosure recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Wiring and supply water piping requirements
Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Supply water piping requirements for all water types . . . . . . . . . . . . . 5
Supply water piping
Tap/softened water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
RO/DI water option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Supply water flow rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Supply water guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Drain piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Gas piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Combustion and ventilation air
Room air combustion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Sealed combustion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Venting
General venting guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Outdoor enclosure venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Vertical venting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Horizontal venting requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Operation
Start-up checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Maintenance
Cool-down procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Shutdown procedure: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Inspection and maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Inspection recommendations
RO/DI water quality recommendations . . . . . . . . . . . . . . . . . . . . . . 17
Inspection intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Inspection items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Burner assemblies and heat exchanger tubes . . . . . . . . . . . . . . . . . 18
Burner maintenance frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Burner maintenance instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Burner tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Back cover

1
DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
Important:
This equipment is for use with the
following appliance categories.
Contact your distributor before
converting to another group or supply
pressure.
Table 1-1:
Appliance categories
I2H G20 at 20 mbar
I2E G20 at 20/25 mbar
I2E+ G20/G25 at 20/25 mbar
I2L G25 at 25 mbar
I3+(28-30/37) G30 Butane at 28-30 mbar and
G31 Propane at 37 mbar
I3B/P(30) G30 Butane and
G31 Propane at 30 mbar
I3B/P(37) G30 Butane and
G31 Propane at 37 mbar
I3B/P(50) G30 Butane and
G31 Propane at 50 mbar
I3P(30) G31 Propane at 30 mbar
I3P(37) G31 Propane at 37 mbar
I3P(50) G31 Propane at 50 mbar
Electrical warning label
Location: Front door and electrical
access door
Definition: Electrical shock hazard
An input derate exists when operating
GTS humidifiers at a high altitude.
Table 1-2:
Input derate for high altitude
Altitude (meters) Input derate %
0 – 610 0
611–765 2
766–915 4
916–1065 6
1066–1220 8
1221–1370 10
1371–1525 12
1526–1675 14
1676–1830 16
1831–1980 18
1981–2135 20
2136–2285 22
2286–2440 24
2441–2590 26
2591–2743 28
2744–2895 30
2896–3048 32
3049–3200 34
3201–3352 36
3353–3505 38
3506–3657 40
This equipment has been tested by
Intertek to the Low Voltage, Gas
Appliance, and EMC directives and
has been certified by Certigaz for use
in all EU countries.
GTS humidifiers bearing the CE
mark are authorized for use in the
European countries listed below.
Table 1-3:
Authorized countries of destination
Austria (AT) Latvia (LV)
Belgium (BE) Lithuania (LT)
Bulgaria (BG) Luxembourg (LU)
Cyprus (CY) Malta (MT)
Czech Republic (CZ) Netherlands (NL)
Denmark (DK) Norway (NO)
Estonia (EE) Poland (PL)
Finland (FI) Portugal (PT)
France (FR) Romania (RO)
Germany (DE) Slovakia (SK)
Greece (GR) Slovenia (SI)
Hungary (HU) Spain (ES)
Iceland (IS) Sweden (SE)
Ireland (IE) Switzerland (CH)
Italy (IT) United Kingdom (GB)
Table 1-4:
Gas specifications for GTS models
GTS
model
Volumetric flow rate by gas category Average
flue
temperature
at 100%
demand
Minimum
draught
requirement
Mass flow
rate of
combustion
products
2H-G20-20 mbar
2E-G20-20 mbar
2Es-G20-20 mbar
2L-G25-25 mbar
2LL-G25-20 mbar
2Ei-G25-25 mbar
2E+G20/G25-20/25 mbar
2ER-G20/G25-20/25 mbar
3B-G30-30 mbar
3B-G30-50 mbar
3P-G31-30 mbar
3P-G31-37 mbar
3P-G31-50 mbar
100 2.31 m3/h 2.82 m3/h 2.31-2.82 m3/h 1.31 m3/h 1.49 m3/h 200 °C –0.025 mbar 6.9 g/s
200 4.62 m3/h 5.64 m3/h 4.62-5.64 m3/h 2.62 m3/h 2.98 m3/h 220 °C –0.025 mbar 13.8 g/s
300 6.93 m3/h 8.46 m3/h 6.92-8.46 m3/h 3.93 m3/h 4.47 m3/h 190 °C –0.025 mbar 20.7 g/s
400 9.24 m3/h 11.28 m3/h 9.24-11.28 m3/h 5.24 m3/h 5.96 m3/h 220 °C –0.025 mbar 27.6 g/s
500 11.55 m3/h 14.10 m3/h 11.55-14.10 m3/h 6.55 m3/h 7.45 m3/h 220 °C –0.025 mbar 34.5 g/s
600 13.86 m3/h 16.92 m3/h 13.85-16.92 m3/h 7.86 m3/h 8.94 m3/h 220 °C –0.025 mbar 41.4 g/s
700 16.17 m3/h 19.74 m3/h 16.17-19.74 m3/h 9.17 m3/h 10.43 m3/h 220 °C –0.025 mbar 48.3 g/s
800 18.48 m3/h 22.56 m3/h 18.47-22.56 m3/h 10.48 m3/h 11.92 m3/h 220 °C – 0.025 mbar 55.2 g/s
Before you begin

2DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
The GTS humidifier has a number of safeguards to ensure proper operation:
• When there is a call for humidity, all of the combustion blowers must start. Each combustion
blower sends a signal to the microprocessor relaying its speed. If the speed is outside an
acceptable range, the GTS will not operate.
• The negative-pressure gas valves used on the GTS humidifier are designed to keep a constant
ratio of air and gas throughout the operating range of the blower. If the blower fails to run, the
GTS humidifier will shut down due to a blower fault.
• If the flue becomes blocked, the blocked flue sensor will shut down the humidifier.
• During operation, the water level in the tank is monitored by a probe system for
tap/softened water humidifiers and by a low water float switch for humidifiers with the RO/DI
water option (see Figure 3-1).
These water level monitors tie into the Vapor-logic controller. If the water level drops below a
safe point, the controller turns the burners off and tries to fill the tank. If unable to fill the tank
within a defined time period, an “Excessive refill time” alarm appears in the Vapor-logic Alarm
Log. The burners remain off until this alarm is cleared.
• In tap/softened water applications, the water level in the tank is also monitored by a redundant
low-water system that operates independently of the Vapor-logic controller. This system is tied
directly into the power source for the gas valves. If this system detects a low water condition,
the humidifier shuts down until water is present. A “GTS low water alarm” will be active while
the condition exists.
• There is a temperature sensor near the top of the heat exchanger. If the water level drops too
low and both the main and redundant low water sensors fail to detect it, the temperature sensor
shuts down the humidifier to prevent an unsafe condition.
• There is a limit-control thermal trip next to the temperature sensor. This thermal trip operates
independently from the Vapor-logic controller. If the water level drops below the heat
exchanger, the thermal trip will directly shut down the gas valves. The thermal trip has a red
button that must be manually reset before the burners are able to fire again.
Safeguards

3
DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
Fill valve Float
Fill valve closes when water level
rises to this probe.
Fill valve opens when water level
is below this probe.
Controller disables burner if water level
drops below this probe.
Heat exchanger
Open drain
Water tempering device
Air gap
Drain piping
Drain valve
Subpanel/control components
Flue connection
Overflow outlet
Gas valve
Blower
Supply water line
Redundant probe
(Redundant low water cutoff switch
if DI/RO water option)
Water level probe
(Float-operated low water cutoff switch
if DI/RO water option)
Thermal trip
Temperature sensor
Tap/softened water
GTS humidifier shown
Steam hose or tubing
Steam outlet
Humidifiers using tap or softened water control water levels
electronically using a three-rod probe. A redundant probe is used
as a safety device.
Humidifiers with the RO/DI water option control water level using a
float valve. A low-water cutoff switch and a redundant low-water cutoff
switch are used as safety devices.
FIGURE 3-1: GTS HUMIDIFIER COMPONENTS AND WATER LEVEL CONTROL TYPES
DI/RO water optionTap/softened water
OM-1247
Product overview

4DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
Finding a location
WARNING
Installation requirements:
Installation must conform to the requirements of local and national directives and regulations for the installation of
gas-fired equipment.
The humidifier must be installed by a qualified technician and meet the requirements of all governing codes.
Failure to follow these instructions could cause severe bodily injury or death.
• Provide a level, solid foundation for the humidifier.
• Locate the humidifier as near as possible to a chimney or outside wall so that the flue pipe from the humidifier is
short and direct.
• Install the humidifier where its electrical components are protected from water during operation and service.
• Install the humidifier in a location away (and protected) from drafts. If installed in a separate room, follow the
instructions concerning combustion and ventilation air.
• Install the humidifier in an area where leakage from the tank or its connections will not result in damage to the
adjacent structure or to lower floors of the structure. When such locations cannot be avoided, install a suitable drain
pan (adequately drained) under the humidifier. The pan must not restrict combustion airflow.
• If located in an insulated space, keep the humidifier free and clear of insulating materials. Insulating material can be
combustible. Inspect the humidifier area when the humidifier is installed or when insulation is added.
460 mm
920 mm
760 mm
OM-1222a
• DriSteem recommends 25 mm minimum clearance between back
panel and combustible surfaces.
• These clearance recommendations are provided to provide access
and to prevent property damage from heat. To further safeguard
property, protect heat-sensitive walls and surfaces (wood, plastic,
etc.) with suitable insulation.
FIGURE 4-1: CLEARANCE RECOMMENDATIONS
Side door:
Electrical access
75 mm
Flue piping
Vertical section of flue must be at least 1.5 meters or meet all governing
codes, whichever is longer. DriSteem recommends installing a high-wind
vent cap on all GTS humidifiers.
Outdoor enclosure
back wall
Clearance required behind outdoor
enclosure for steam outlet
GTS humidifier
back panel
Front door:
Burner, blower, gas valve, and plumbing access
OM-1228LWa
Vent cap
FIGURE 4-2: OUTDOOR ENCLOSURE RECOMMENDATIONS
Back panel:
No ventilation
louvers

5
DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
Wiring and supply water piping requirements
WIRING
WARNING
Installation must meet the requirements of governing codes or, in the absence of governing codes, in accordance
with IEE wiring regulations (BS7671). Failure to follow these instructions could cause a fire, resulting in severe
bodily injury, death, or significant property damage.
Follow the instructions below for GTS humidifier wiring:
• Use only copper wire.
• GTS humidifiers must be supplied with 230 Vac, 50 Hz, separately fused electrical service.
• The electrical subpanel must have an uninterrupted earth ground to minimize personal injury if an electrical fault
should occur. Install in accordance with existing electrical codes.
• Do not use gas piping as an electrical earth ground.
• All electrical components and wiring must be protected from mechanical damage and water.
• Check the electric current characteristics and capacity requirements against the nameplate. All wiring must be in
accordance with the governing codes listed above and with the GTS wiring diagrams.
SUPPLY WATER PIPING REQUIREMENTS FOR ALL WATER TYPES
Follow the GTS humidifier supply water piping instructions below for all water types. Install supply water piping in
accordance with locally applicable installation regulations.
• Provide a shutoff valve and union in the supply water line to isolate the humidifier from the water system while
servicing.
• To minimize electrolytic corrosion, install insulating unions to make connections between copper and other dissimilar
metal fittings, such as galvanized steel.
• Humidifier tank must be full of water — and supply water free to flow into the tank — before the ignition sequence
of a newly installed humidifier is initiated.
• If planning to use heated supply water, disconnect the supply water line from the water tempering device fill
manifold/tee. Install a pipe plug in the manifold/tee, and reconnect the water tempering device line to a cold water
supply.
• The supply water pressure range must be 172 kPa minimum with fill valve open to 552 kPa maximum with fill valve
closed. When using nonmetallic tubing for supply water, it must be rated for 100 °C minimum continuous operating
temperature. DriSteem recommends installing a 1 m piece of noninsulated stainless steel pipe directly off the
humidifier prior to connecting to the nonmetallic tubing.
• Before connecting piping to the GTS humidifier, thoroughly flush the supply water piping to prevent pipe residue
and stagnant water from getting into the humidifier tank.
General supply water piping information:
• The end-of-season feature shuts off the supply water and drains the tank when there is no demand for humidity for
72 hours. This is a default setting and is user-adjustable.
• The humidifier has a 25-mm internal air gap to prevent back siphoning into a potable water system. Some
governing codes may require additional protection, such as a vacuum breaker or backflow preventer.
• The supply water assembly has a DN10 pipe thread connection.

6DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
Supply water piping
TAP/SOFTENED WATER
The primary component of the supply water assembly is a solenoid valve,
which may cause noise during fill cycles.
During a fill cycle, cold supply water drops the internal tank temperature and
may collapse the boil, which can cause a low rolling sound. To minimize this,
use hot supply water.
In cases where water hammer occurs when the fill solenoid closes, a shock
arrester is recommended. Reducing the supply water pressure (minimum
172 kPa with fill valve open) or using flexible tubing (rated for 100 °C
minimum continuous operating temperature) may diminish the noise.
The minimum water conductivity for the GTS tap/softened water model
is 30 µS/cm.
RO/DI WATER OPTION
The water level in GTS humidifiers with the RO/DI water option is controlled
with a float valve. For models with the end-of-season drain option, a solenoid
valve is installed prior to the float valve.
When using nonmetallic tubing, DriSteem recommends the installer place a
50-mm water seal/loop in the supply water line to isolate steam during RO/DI
water system maintenance.
DriSteem highly recommends installing a strainer in the supply water line
to prevent clogging of the solenoid valve or float valve orifice. The strainer
prevents particulate from collecting at the solenoid valve seat.
To minimize RO/DI water waste, disconnect factory piping to the water
tempering device and pipe directly to a tap water source.
WARNING
Fire hazard if using tap/softened supply water with RO/DI water option:
If a GTS humidifier with the RO/DI water option is supplied with
tap/softened fill water, the float valve assembly will become clogged,
and particulate will accumulate on the low water cutoff switch (float
switch). This will cause failure of a critical safety circuit and the potential
for a dry tank fire, which can cause severe property damage, severe
personal injury, or death.
SUPPLY WATER FLOW RATES
The rate of supply water flow into the GTS humidifier tank is determined by the
supply water pressure and the inlet valve. See Table 6-2.
mc_071912_1545
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 6-1.
Table 6-1:
DriSteem supply water guidelines
Chlorides*
RO or DI water
Softened water
Tap water
* Damage caused by
chloride corrosion is
not covered by your
DriSteem warranty.
< 5 ppm
< 25 ppm
< 50 ppm
Total hardness
Tap water < 500 ppm
pH
RO, DI, or softened
water
Tap water
7 to 8
6.5 to 8.5
Silica < 15 ppm
You may wish to take action to mitigate
potential negative effects to your
humidifier. Supply water outside of these
guidelines may void your DriSteem
warranty. Please contact your DriSteem
distributor if you need advice.
Table 6-2:
Supply water flow rates (liters per minute)
Supply
water
pressure
Solenoid valve flow rates
(tap/softened water)
Float valve flow rates (RO/DI water)
Models 100 – 400 Models 500 – 800
200 kPa 7.2 6.7 17.0
350 kPa 9.0 8.8 22.5
450 kPa 10.2 9.9 25.4
550 kPa 11.1 10.8 27.6

7
DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
The drain line piped from the humidifier must be run to an approved sanitary waste or suitable drain. Although the GTS
humidifier is equipped with integral water tempering, if nonmetallic drain pipe or hose is used, DriSteem recommends it
be rated for 100 °C minimum continuous operating temperature.
• Minimum drain pipe size is DN40 inside diameter. Do not reduce the size of the drain piping. If the length of the
drain piping exceeds 3 m, increase the pipe size. If combining multiple drain lines, ensure proper common pipe
sizing practices are used.
• Do not install the humidifier directly above a floor drain — skim and drain water dumped into the drain will cause
flash steam, which will rise and saturate electrical components, adversely affecting their life and performance.
• An open drain with a 25-mm air gap between the drain piping and the drain is required. Locate the air gap only
in spaces with adequate temperature and air movement to absorb flash steam; otherwise, condensing on nearby
surfaces may occur.
• Drain piping downstream from the water seal must be pitched a minimum of 1% toward the drain. Governing codes
may require more pitch.
• If the proximity of a drain requires the humidifier drain and skim water to be lifted, use a water pump with capacity
of at least 45.4 liters per minute. A check valve is required on the discharge of the pump. Electrical power for the
pump is independent of the humidifier.
• The GTS humidifier has an auxiliary DN40 drain outlet below the subpanel. This drain outlet can be hard-piped
during installation to enable rapid tank draining before maintenance. Next to this outlet is a cleanout plate that
provides access for removing scale from the tank bottom.
Drain piping

8DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
Important:
The required supply pressure is 20 or 25 mbar for natural gas and 30, 37, or 50 mbar for propane gas.
WARNING
Fire hazard:
Supply the humidifier only with the gas type (natural gas or LP gas) listed on the humidifier name plate. Failure
to supply the humidifier with the listed gas type could result in burner failure or a fire, causing property damage,
personal injury, or death.
Follow the GTS humidifier gas piping instructions below. Conform to local and national directives and regulations for the
installation of gas-fired equipment.
• After threading and reaming ends of pipes, inspect piping and remove loose dirt and chips.
• Support piping so there are no strains imposed on humidifier or controls.
• Use two wrenches when connecting piping to humidifier or controls.
• Provide a drip leg before each humidifier and in the line where low spots cannot be avoided.
• Take-off to humidifier should come from top or side of main to avoid trapping condensate.
• Piping that is subject to wide temperature variations should be insulated.
• Pitch piping up toward humidifier at least 6 mm per 4.5 m of horizontal run.
• Compounds used on threaded joints of gas piping must be resistant to the harmful action of liquefied petroleum
gases.
• Install a ground joint union and a manual shutoff valve immediately upstream of the humidifier.
• Do not use flexible connectors.
• Allow at least 1.5 m of piping between any high pressure regulator and humidifier pipe connection.
• Piping installation must conform to the requirements of the authority having jurisdiction or, in the absence of
such requirements, must conform to local and national directives and regulations for the installation of gas-fired
equipment.
Gas piping

9
DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
• When the specific gravity of the gas is other than 0.60 for natural gas or 1.53 for propane, refer to Table 9-1.
• Piping to GTS humidifiers should conform with local and national requirements for type, volume, and gas handled
and for pressure drop allowed in the line. Refer to the tables on this page to determine the gas flow in m3/hr for the
type of gas and size of humidifier to install. Using this value and the length of pipe necessary, determine the pipe
diameter.
Where several GTS humidifiers are served by the same main, the total capacity, gas flow, and length of main must
be considered. Avoid pipe sizes smaller than DN15. Table 9-2 allows for the usual number of fittings with a 0.7
mbar pressure drop.
WARNING
Fire or explosion hazard:
Purge air before lighting humidifier burners by disconnecting piping at gas control. In no case should line be
purged into heat exchanger. Failure to follow these instructions could cause a fire or explosion, resulting in bodily
injury, death, or significant property damage.
Gas pressure test gauge
Install a DN6 plugged tapping, accessible for test gauge connection, immediately upstream of the gas supply
connection to the appliance. Use this tap to check pressure with all burners running.
Leak testing
After installation, check field piping and humidifier gas train for gas leaks.
• Do not use soap solution or open flame on humidifier gas train. A gas leak detector is recommended.
• When leak-testing the gas supply piping system, isolate the humidifier from the gas supply piping system by closing
its field-installed manual shutoff valve whenever pressure is greater than 60 mbar.
Table 9-2:
Gas pipe capacities for gas pressures of 3.45 kPa or less
Length of pipe
Gas flow in piping in m3/hr at pressure drop of 0.07 kPa
Specific gravity = 0.60
Nominal iron pipe diameter in inches (DN)
DN15 DN20 DN25 DN32 DN40
mm
3/hr m3/hr m3/hr m3/hr m3/hr
3 3.7 7.9 14.7 29.7 45.3
6 2.6 5.4 9.9 20.7 31.1
9 2.1 4.3 8.1 16.7 25.2
12 1.8 3.7 6.9 14.2 21.5
15 1.6 3.3 6.1 12.5 19.0
18 1.4 3.0 5.5 11.3 17.3
21 1.3 2.7 5.1 10.5 15.9
24 1.2 2.5 4.8 9.9 15.0
27 1.1 2.4 4.5 9.1 13.9
30 1.1 2.2 4.2 8.6 13.0
Table 9-1:
Specific gravity conversion factors
Natural gas
Specific gravity Factor
0.55 1.04
0.60 1.00
0.65 0.962
Propane gas
Specific gravity Factor
1.50 0.633
1.53 0.626
1.60 0.612
Note: Use the above multiplying factor with
Table: 9-2 when the specific gravity of
gas is other than 0.60 (natural gas) or
1.53 (propane).
Gas piping

10 DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
The GTS humidifier supports both room air and sealed combustion.
• Do not install the humidifier in a dusty environment.
• When the GTS humidifier is installed in an environment with negative pressure or toxic air, it must have sealed
combustion.
ROOM AIR COMBUSTION
WARNING
Air for combustion:
Air for combustion must not be contaminated by halogen compounds, which include fluoride, chloride, bromide,
and iodide. These elements are found in aerosol sprays, detergents, bleaches, cleaning solvents, salts, air
fresheners, and other household products.
Failure to follow these instructions could cause severe bodily injury or death.
• All fuel-burning equipment must be supplied with air for combustion. Sufficient air must be provided to ensure there
is not a negative pressure in the equipment room or space.
• Do not block or obstruct air openings on the appliance, spaces around the appliance, or air openings to the
appliance area.
• Do not block the flow of combustion and ventilation air. To provide necessary oxygen for proper combustion,
openings must be provided to allow outside air to enter the space where the humidifier is located. Enclosed spaces,
such as equipment rooms, must be vented for combustion air. The size of air openings must be based on all gas-
burning equipment installed in the space. Table 10-1 outlines four types of locations, and the requirements of each.
Combustion and ventilation air
Table 10-1:
Location of humidifier and required air openings
Location description Required air opening
Confined space with all air from inside the building; conventional frame, brick or
stone construction with normal infiltration
Note: this location rarely provides enough air for higher-capacity humidifiers.
Two openings, 6.5 cm2per opening per 293 W input
The minimum free area of all openings combined is 645 cm2.
Confined space with all air from outside the building through air ducts Two openings, 2 ducts, 6.5 cm2per opening per 586 W
input*
Confined space with all air from outside the building from through-wall openings
only (no ducts)
Two openings, 6.5 cm2per opening per 1172 W input*
Unconfined space with all air from outside the building Same as confined space; all air from outside the building
* The minimum dimension of any opening is 76 mm × 76 mm.

11
DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
SEALED COMBUSTION
WARNING
Requirement for manifolding sealed combustion piping runs:
When installing sealed-combustion piping for more than one GTS humidifier, do not commonly manifold multiple
sealed combustion piping runs without having the manifold sized for the specific installation by a licensed
engineer. Failure to follow these instructions could starve the GTS humidifier of combustion air resulting in either
the burners not being able to light or high carbon monoxide levels, which may cause severe personal injury or
death.
The GTS humidifier supports sealed combustion using DN100 PVC or CPVC piping. All GTS models have a single-point
connection to the blower inside the front door. See Figure 11-3.
When running PVC or CPVC piping for sealed combustion, the maximum allowable distance to the outdoor air source is
21.3 m including 2.1 m equivalent length for each elbow. The outside air source opening must be covered with a large
mesh screen to prevent the introduction of unwanted materials without restricting airflow.
If sealed combustion piping is less than 6 m in length, DriSteem recommends insulating the piping to prevent
condensation.
SEALED COMBUSTION OR OUTDOOR ENCLOSURE
To ensure a supply of clean, fresh air, the GTS humidifier combustion air must be at least 3 m away from any
mechanical exhaust outlet.
Combustion and ventilation air
DN100 PVC or CPVC combustion air intake
OM-1225
FIGURE 11-3: GTS OPTIONAL SEALED COMBUSTION CONNECTION
Front door

12 DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
• The GTS humidifier is a Fan Assisted Category I
(natural draft) Appliance. It is a Class B23 appliance,
without a draught diverter, with a combustion
air blower upstream of the heat exchanger. A
GTS humidifier with the sealed combustion option is
a Class C53 appliance. Installations where the vent
terminates in a side wall of the building, or where the
overall horizontal run exceeds the overall vertical run,
require a power venter.
• Maximum flue temperature under normal operating
conditions is 205 °C plus ambient.
• Maximum abnormal-operation flue temperature is
348 °C plus ambient.
• Flue draft negative pressure greater than 50 Pa may
cause unacceptable post ignition.
• Vent piping must be approved for a Category I
appliance. Do not use more than one type of venting
per application.
• Vent terminal must be at least 1 m above any forced
air inlet located within 3 m.
• Do not use vent equipment from more than one
manufacturer.
• When connecting the humidifier to a gas vent or
chimney, installation must conform to:
– Local and national directives and regulations for
the installation of gas-fired equipment
– Governing and building codes
– Vent manufacturer’s instructions
• When applying the codes, see also the venting
manufacturer's instructions, the service gas supplier's
regulations, and the specific instructions provided in
this manual.
• Inspect for proper and tight construction. Remove any
restrictions or obstructions. An existing chimney may
require cleaning.
• Do not connect this humidifier to a chimney flue
servicing a separate appliance designed to burn solid
fuel.
• Never connect this humidifier to a chimney serving a
fireplace, unless the fireplace opening is permanently
sealed off.
• Code prohibits venting into an unlined masonry
or concrete chimney. If the humidifier is connected
to a lined, masonry chimney, the chimney must be
sized and installed according to the provisions of the
governing codes.
Venting
• Vent connector serving this appliance shall not be
connected into any portion of mechanical draft
systems operating under positive pressure.
• Add insulation to any roof or wall penetration vent
connector that is exposed to ambient temperatures of
0 °C or less, especially any application using single-
wall vent pipe as a connector.
• Do not insulate vent pipe exposed to outdoor weather
conditions (e.g., above roof lines).
• Install vent piping as straight as possible, with a
minimum number of turns or elbows.
• Maintain a minimum upward slope of 2% on all
horizontal runs.
• Rigidly support the vent pipe every 1.5 m or less with
hangers or straps to ensure there is no movement after
installation. The humidifier vent box should not support
the weight of the vent piping.
• No portion of the vent system should extend into, or
pass through, any circulation air duct or plenum.
• Install and fire-stop all vent pipe passing through
floors, ceilings, and walls with the proper clearances
from combustible material according to local and
national directives and regulations for the installation
of gas-fired equipment.
• In replacement installation where an existing vent
system may be used, inspect the vent system for
condition, size, type of vent material, and height to
meet the requirements in these instructions.
CAUTION
Flue condensate removal
Install a drip leg or flue box condensate drain for start-
up flue condensate removal. Failure to follow these
instructions could cause water to accumulate in the
flue box.
OUTDOOR ENCLOSURE VENTING
The vertical section of flue must be at least 1.5 meters or
meet all governing codes, whichever is longer. DriSteem
recommends a drip tee directly after the factory-supplied vent
connection. DriSteem recommends a high-wind vent cap on
all GTS humidifiers. See Figure 4-2.
GENERAL VENTING GUIDELINES
WARNING
Installation requirements:
The humidifier must be installed by a qualified technician and meet the requirements of all governing codes.
Failure to follow these instructions could cause severe bodily injury or death.

13
DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
VERTICAL VENTING REQUIREMENTS
• Do not reduce the vent diameter.
• If turns are required in the vent piping, make
sweeping bends; avoid small-radius turns.
• Use the same size stack as the vent furnished with the
humidifier.
• Maintain proper support of vent connections and
joints.
• Observe clearances (in accordance with applicable
codes) from all combustible materials and install an
approved cap for the stack outlet.
• The bottom of the cap must be one stack diameter
above the top of the stack.
• Extend chimney or vent at least 1 m above its passage
through a roof and at least 0.6 m above any ridge
within 3 m of the chimney (governing codes apply).
• The vent system must terminate above the roof surface
per the local and national directives and regulations
for the installation of gas-fired equipment. DriSteem
recommends installing a high-wind vent cap on all
GTS humidifiers.
• This humidifier may be commonly vented with other
listed Category I gas-fired appliances. Total input rates
of all appliances determines the vent size.
Venting
HORIZONTAL VENTING REQUIREMENTS
• Contact your DriSteem distributor for all horizontal
venting parts.
• Ensure that distances from vent terminal to adjacent
public walkways, buildings, and openable windows
and building openings are consistent with local and
national directives and regulations for the installation
of gas-fired equipment.
• In areas accessible to the public, vent terminal must
be at least 2.1 m above ground level to prevent burns
from hot terminal surface.
• The vent terminal and air intake locations must be
at sufficient height above ground level to prevent
blocking by expected snowfall.
• Maintain minimum horizontal clearance of 1.2 m
from electric meters, gas meters, regulators, and relief
equipment.
• Building materials must be protected from degradation
by flue gases.
• Vent box pressure must be –2.5 Pa. Set by adjusting
power venter and barometric damper with all burners
running (see manufacturer's instructions included with
power venter and damper).
WARNING
Horizontal venting with a vertical termination:
For applications where the vent pipe terminates in
a vertical position, the horizontal length must not
exceed the height of the vent unless a power venter
is used. Failure to follow these instructions could
cause flue gases to exit the vent piping, causing
severe personal injury or death.

14 DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
Operation
START-UP CHECKLIST
After the system is installed and connected to gas, electrical, water supplies, and controls, check the following items:
☐Verify that the GTS humidifier, controls, piping, electrical connections, steam supply, and dispersion units are
installed according to the following:
• Installation instructions in this manual
• Vapor-logic version 5 Installation and Operation Manual (shipped with the humidifier)
– Installation section
– Installation checklist
• Ladder style wiring diagram (shipped inside humidifier)
• External connections wiring diagram (shipped inside humidifier)
• Gas connection instructions in this manual
• Mounting instructions in this manual
• All governing codes
☐Piping (gas)
• Verify that the gas type supplied to the humidifier matches the humidifier nameplate label.
• Verify that all field-installed and humidifier gas piping has been tested for leaks.
Note: Soap and water are not recommended for leak testing. See “Leak testing” on page 9.
☐Piping (steam, drain, supply water)
Verify that all piping connections have been completed as recommended and that water pressure is available.
☐Electrical
Verify that all wiring connections have been made in accordance with all governing codes and the GTS wiring
diagrams.
☐Control wiring
Verify that all control wiring has been completed as specified and required for correct and safe operation of the
GTS humidifier.
☐Tank
Verify that the humidifier tank is:
• Securely installed and level before filling with water.
• Level from front to back and from side to side after it is full of water.
START-UP
WARNING
Only qualified electrical and gas personnel should perform start-up.
Refer to the Vapor-logic version 5 Installation and Operation Manual for
details about commissioning, menu navigation, firmware updates, humidifier
troubleshooting, and more.
During start-up and operation, the humidifier operating status appears on
the Vapor-logic keypad/display Home screen (Figure 14-1). Do not leave
the humidifier unattended during initial start-up; monitor operation through
multiple fill cycles.
To change Mode or Set point:
1. Press Up or Down arrow to highlight Set point or Mode, then press Enter
to confirm selection.
2. Press Up or Down arrow to increase or decrease highlighted value, then
press Enter to confirm.
Note: For example, to create a call for humidity, increase SET PT to an RH
that is higher than the displayed SPACE RH.
Press this softkey
to access Status,
Diagnostics,
Alarms, and Setup.
Press arrow keys
to navigate or to
change values.
Press Enter to
confirm selections.
FIGURE 14-1: HOME SCREEN
Mode and set point can be changed from the
Home screen. Other parameters displayed here
can be changed in the Setup menu.

15
DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
INSPECTION AND MAINTENANCE
1. Annually (also recommended when maintenance is
performed)
• Inspect tank, piping, and gaskets for water and
gas leaks.
• All safety devices in the control circuit should be
cycled on and off to verify they are functioning.
These include:
– High limit switch
– Airflow proving switch
• Tap/softened water humidifiers only:
– Low water level probe. Pull out probe plug; fill
valve should energize.
– Redundant low water level probe
• Humidifiers with the RO/DI water option only:
– Verify that the float valve is closing off. If the
float valve will not shut off, there may be
particulate on the valve seat, or the seat may
be worn and in need of replacement.
– NOTE: As long as mineral-free water is used
in the GTS, no cleaning or flushing of the
humidifier should be necessary.
2. Seasonally (or as required, depending on water
quality)
Tap/softened water humidifiers only:
• Clean tank:
– Remove cleanout plate, and dispose of any
loose scale that has collected in the tank.
Do this before the scale buildup reaches the
bottom of the heat exchanger.
– Inspect the area inside the tank in front of the
drain valve fitting, and thoroughly clean all
scale and mineral buildup from that area.
• Dismantle and clean drain valve and associated
piping.
Maintenance
COOL-DOWN PROCEDURE
Before performing these maintenance procedures, allow
the tank to cool down as described here.
NOTE: Insulated and uninsulated tanks will have hot
surfaces.
Verify that there is no call for humidity and that the
aquastat set point (adjusted using the keypad/display
Setup screens) is less than room temperature (default
setting is 4 °C) so the burners do not energize.
• GTS models with RO/DI water option and a ball valve
drain:
1. Manually open the ball valve, and allow
approximately half of the water to drain out of the
tank.
The float valve opens after the water level in the
tank begins to drop.
2. Let the fill water run until the tank is cooled; then
shut off the field-installed manual supply water shut-
off valve.
3. Let the tank drain; then manually close the drain
valve.
• GTS models with tap/softened water and any model
with end-of-season drain:
1. From the Main menu, enter the Tank Status
submenu.
2. Change mode to Drain, and allow approximately
half the water to drain out of the tank.
3. Change the mode back to Auto; the fill valve opens
and the humidifier cools down.
4. When the fill valve closes, go back into Drain
mode, and allow the tank to drain completely. The
humidifier should be cool enough to work on.
WARNING
Shutdown procedure:
To prevent severe personal injury or death from
electrical shock, fire, or explosion, follow this
shutdown procedure before performing the
following service or maintenance procedures on this
humidifier.
1. Use Vapor-logic keypad/display, change the
control mode to Standby.
2. Place all power disconnects in OFF position and
lock in OFF position.
3. Close field-installed manual supply water shut-off
valve.
4. Close gas shut-off valves.

16 DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
Seasonally (continued)
• Clean the probes
– Access the probe assembly either from the
electrical panel or by removing the roof panel
above the electrical area.
– Disconnect the probe plug and cable assembly,
and unscrew the probe rod assembly from the
humidifier probe housing.
– Clean the probe housing, ensuring that all the
housing passageways are clear. Remove the
housing from the tank by removing the cover
plate from the tank.
Note: The scale should flake off easily from the
probe assembly rods.
– The bottom 10 mm of each rod is the sensing
portion; clean these areas with a wire brush,
emery cloth, 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 assembly.
• Clean the skim/overflow port
– Water should drain from the skimmer drain
pipe after each fill cycle. This should be verified
visually by a weekly inspection.
– Loosen deposits in and around the skimmer/
overflow port with a screwdriver or similar tool.
– If flow through the water seal/P-trap is
diminished due to mineral accumulation:
- Remove the water seal piping from the
humidifier, and flush it out.
- Replace the water seal with new piping if the
minerals have hardened in the water seal.
• Clean the low water cutout probe:
Remove the electrical access panel, and inspect the
probe rod for mineral accumulation. The probe rod
is located on the top of the tank near the back. Use
a wire brush, emery cloth, or steel wool to clean
the probe rod.
• Inspect blower motor. Lubrication is not required.
• Remove dust with a vacuum:
Remove all dust from areas around the motor, vent
fan(s), and louvers that allow air to the shrouded
area.
Maintenance
• When the maintenance requirements are complete:
– Replace cleanout plate, and tighten the nuts.
Torque nuts to 25 to 35 in-lb (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.
– Verify that the drain valve assembly is in the
closed position.
– Replace and secure all covers and doors.
– Turn on water supply.
– Turn on electrical power.
– Turn on gas.
– Do not leave humidifier unattended. Allow
humidifier to cycle through multiple fill cycles,
and verify that humidifier cover, cleanout plate,
and probe holder gasket are not leaking.
3. Off-season maintenance
• Tap/softened water humidifiers:
Inspect and clean the following:
– Probe rods
– Skimmer port and water seal
– Humidifier tank and gaskets
– Heat exchanger
After cleaning, the humidifier should remain empty
until humidification is required.
• Humidifiers with the RO/DI water option:
Inspect the following:
– Float valve
– Low-water cutoff switch
– Redundant low water cutoff switch

17
DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
INSPECTION INTERVALS
• By the user every 30 days.
• Appliance system inspected once a year by a qualified service person.
INSPECTION ITEMS
• Proper field operation of burner. Measure CO ppm, CO2%, O2%, flue temperature, and burner efficiency at 100%
demand with the tank at a boil. Verify that measurements are within the guidelines described in burner tuning.
• Burner flame is blue or orange in color — up to 6 mm from the surface of the burner.
WARNING
Shutdown procedure:
Perform the shutdown procedure on page 15 before proceeding.
• Inspect flue passageways external to the appliance, such as vent connector and chimney. Make sure they are clear
and free of obstructions.
• Ensure that vent connector is in place, sloping upward, and physically sound without holes or excessive corrosion.
• Ensure that physical support of the humidifier is sound without sagging, cracks, or gaps between floor stand or tank
flanges.
• Ensure that there are no obvious signs of deterioration of the humidifier.
RO/DI WATER QUALITY RECOMMENDATIONS
• Verify regularly that water processing equipment is operating correctly. The presence of chlorides in improperly
processed DI water can cause pitting and failure of the tank and heat exchanger.
• GTS humidifiers with the RO/DI water option do not require regular cleaning, although regular inspections are
advised.
• GTS humidifiers with the RO/DI water option do not require skimming or draining and flushing to remove
precipitated minerals. However, at the end of a humidification season, drain the humidifier either by manually
opening the drain valve. If the humidifier was purchased with end-of-season drain, it is already programmed to
drain.
Inspection recommendations

18 DRISTEEM GTS HUMIDIFIER INSTALLATION AND OPERATION MANUAL
BURNER ASSEMBLIES AND HEAT EXCHANGER TUBES
This is not a regular maintenance item, but if the heat exchanger tubes contain carbon deposits, soot, or other residue,
clean as follows:
1. Follow shutdown procedure on page 15.
2. Remove front door of humidifier.
3. Disconnect wiring to blowers, flame sensors, gas valves, and ignition controllers. Remove burner assemblies (each
assembly is mounted with four bolts).
4. Remove vent box.
5. Use a 150 mm flue brush with a 600 mm extension and reversible drill. Work brush in and out of all combustion
chambers.
NOTE: To ease reassembly, disconnect components from one burner assembly at a time, and clean each
corresponding combustion chamber individually.
6. Remove loose deposits and residue that falls into rear header with vacuum cleaner and hose extension.
7. Inspect DN40 return tubes. Clean if necessary.
8. Run thin brush between turbulator and tube wall on all four sides.
9. Reinstall burner assemblies and gaskets, vent box and gasket, all electrical wiring, humidifier front door, and
pressure switch connections.
BURNER MAINTENANCE FREQUENCY
Under normal use conditions, the burner(s) should not need cleaning for a minimum of five years. However, depending
on the operating environment, the burner(s) may require periodic cleaning to remove accumulated materials. Failure
to clean burners can result in reduced humidifier capacity. Use sealed combustion in dirty environments. See burner
maintenance instructions below.
BURNER MAINTENANCE INSTRUCTIONS
To service the burner assembly, clean both the blower and the burner. Remove the blower(s) from the system, and clean
dust from the wheel.
Remove the burner(s) for cleaning.
Removing and cleaning one burner at a time eases reassembly.
To dislodge particulate matter from the burner surface matrix, use compressed air (700 kPa maximum). Keep the air
nozzle about 50 mm from the burner’s surface, blowing air perpendicular to the burner surface while moving the nozzle
back and forth lengthwise. This dislodges particles trapped in the matrix, pushing them back inside the burner.
NOTE: Avoid blowing air across the surface, which tends to have a destructive effect on the burner surface. Allow
particulate matter to fall from the burner through the air/gas inlet. To assist in removing the particulate matter, use
a vacuum at the burner’s air/gas inlet.
Inspection recommendations