XT E le ctrode S te a m H um i di fi e r Installation, Operation, and Maintenance Manual
War nings and cautions Wa r n i n g s a n d c a u t i o n s 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. mc_051508_1145 WARNING Attention installer Read this manual before installing, and leave this manual with product owner.
Wa r n i n g s a n d c a u t i o n s 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.
Ta b l e o f c o n t e n t s Warnings and cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii Overview Product overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Specifications, capacities and weights . . . . . . . . . . . . . . . . . . . . . Fusing and line currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ta b l e o f c o n t e n t s Operation Supply water considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Principle of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Staging multiple XT humidifiers . . . . . . . . . . . . . . . . . . . . . . . . . Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Start-up procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Start-up checklist . . .
Overview Product overview Figure 2-1: Vapor-logic controller interfaces Figure 2-2: XT humidifier installation overview Keypad/display Room RH Mode Duct Set point Output Cylinder status Softkeys for direct menu access System alarms System messages Navigation buttons for item selection Rapid-sorb dispersion panel Steam hose, tubing, or pipe to duct dispersion or XT steam blower (XTSB) Fill cup extension kit required for some models and applications (see Page 11) Electrical knockouts Vapor-logic
Overview Product overview Dispersion options In addition to Rapid-sorb dispersion shown in Figure 2-2, the duct dispersion options below and the open space dispersion options in Figure 3-3 are available for XT humidifiers. See “Dispersion” beginning on Page 23.
Overview Specifications, capacities and weights Table 4-1: XT humidifier specifications Current draw (amps) Max. steam capacity XT model kW 5 1.7 5 10 3.4 20 lbs/hr kg/h Single-phase Shipping weight Three-phase Max. operating weight 120V 208V 230V 240V 277V 480V 600V 208V 240V 400V 480V 600V lbs kg lbs kg 2.3 14.2 8.2 7.4 7.1 — — — — — — — — 47.2 21.4 46.3 21.0 10 4.5 — 16.3 14.8 14.2 12.3 7.1 5.7 9.4 8.2 4.9 4.1 3.3 47.2 21.4 46.3 21.0 6.7 20 9.
Overview Fusing and line currents Table 5-1: Recommended fusing and line currents for XT humidifiers Model XT-5 Phase 1 1 XT-10 3 1 XT-20 3 XT-30 XT-50 XT-75 XT-100 XT-150 XT-200 3 3 3 3 3 3 L1 Line amps L2 120 14.2 14.2 208 8.2 8.2 230 7.4 7.4 240 7.1 208 kW Recommended fusing amps — 1.7 25 — 1.7 15 — 1.7 13 7.1 — 1.7 15 16.3 16.3 — 3.4 25 230 14.8 14.8 — 3.4 25 240 14.2 14.2 — 3.4 25 277 12.3 12.3 — 3.4 20 480 7.1 7.1 — 3.
Overview Dimensions Figure 6-1: XT humidifier dimensional drawings Labeled dimensions: inches (millimeters). See mounting dimensions and electrical knockouts in Figure 8-1. XT models 150 and 200 XT models 5 through 100 Top A E 2.00 (51) 4.1 (102.9) 2.00 (51) Top 2.05 (52.1) A 32.2 (818) 3.05 (77.5) 26.8 (681) E F 1.85 (47) D C 1.
Installation Selecting a location Humidifier Important: When selecting a location for the humidifier, consider the following: Install humidifier only in locations that meet the following temperature and relative humidity (RH) requirements: • Proximity to the duct Install the humidifier near the air duct system where the dispersion assembly will be located. The maximum recommended length for steam hose connecting a single humidifier to a dispersion assembly is 10' (3 m).
Installation Mounting: Keyhole locations and dimensions Figure 8-1: XT humidifier mounting keyhole locations XT models 5 through 100 XT models 150 and 200 D A A G A C D C G E E P B ØN B F H ØN I F I J ØO K J L K M OM-7594 OM-7582 mc_091010_0923 Table 8-1: XT humidifier mounting keyhole dimensions XT models 5, 10, and 20 Dimension 30 and 50 75 and 100 150 and 200 inches mm inches mm inches mm inches mm A 5.00 127 8.15 207 9.62 244 8.00 203 B 16.52 420 18.
Installation Mounting: Clearances Figure 9-1: XT humidifier recommended minimum clearances 16” (400 mm) 3” (76 mm) 15” (380 mm) 3” (76 mm) between units 36” (914 mm) front clearance OM-7583 mc_091010_0922 DRI-STEEM XT Electrode Steam Humidifier Installation, Operation, and Maintenance Manual • Page 9
Installation Mounting Opening and closing cabinet doors To open the cabinet doors, use a slotted screwdriver to rotate the quarter-turn fastener counterclockwise so the slot is vertical. To close the doors, close the right then the left door, and push the quarter-turn fastener while turning clockwise so the slot is horizontal. Unpack the humidifier from the shipping carton, and remove the cabinet doors and steam cylinder.
Installation Fill cup extension kit A fill cup extension kit (Figure 11-1) is required for any of the following: Figure 11-1: Fill cup extension kit • XT humidifier models 75 through 200 (fill cup extension kit ships loose with these models) Fill cup (see inset below) • All XT humidifiers using Ultra-sorb or Rapid-sorb dispersion • All XT humidifiers with more than 20' (6 m) maximum developed length of tubing/pipe from humidifier to dispersion assembly mc_110110_1455 Overflow elbow Removing existing
Installation Steam cylinder Installing steam cylinder Figure 12-1: Steam cylinder installation 1. Make sure strainer is pressed into steam cylinder drain outlet and strainer flange is flush with bottom of cylinder outlet. See Figure 12-1. High water sensor pin 2. Use water to lubricate drain outlet on bottom of cylinder and o-ring in drain valve body. See Figure 12-2. 3.
Installation Piping: Supply water and drain Supply water piping Piping drawings: Use only copper for supply water piping; do not use rubber or plastic. The standard supply water connection before the fill valve is a 1/4" FIP strainer. See the piping drawings on Pages 14 and 15. Note: The supply water connection size is 3/8" BSP [DN10] in Europe. In cases where water hammer may be a possibility, consider installing a shock arrestor. Water pressure must be 25 to 80 psi (175 to 550 kPa).
Installation Piping: XT models 5 through 100 Figure 14-1: XT humidifier field piping overview, models 5 through 100 Steam hose; may also use tubing or pipe. See Table 24-1 for maximum piping lengths. Tubing or pipe must be grounded. Fill valve with 1/4” FIP strainer (3/8" BSP [DN10] in Europe) Install plumb 1” (25 mm) air gap required to isolate drain water from cylinder water.
Installation Piping: XT models 150 and 200 Figure 15-1: XT humidifier field piping overview, models 150 and 200 Steam hose; may also use tubing or pipe. See Table 24-1 for maximum piping lengths. Tubing or pipe must be grounded. Install plumb Fill valve with 1/4” FIP strainer (3/8" BSP [DN10] in Europe) 1” (25 mm) air gap required to isolate drain water from cylinder water.
Installation Piping: XT steam blowers o Figure 16-1: Piping from XT humidifier steam cylinders to XT steam blowers (XTSB) XTSB mounted remotely Maximum recommended distance between humidifier and XTSB is 10’ (3 m).
Installation Piping: XT steam blowers Figure 17-1: Piping from XT humidifier steam cylinders to XTSBs with Y connectors * Water seal is required, whether condensate is piped to open drain or returned to humidifier fill cup.
Installation Piping: XT steam blowers Figure 18-1: Piping from XT humidifier steam cylinders with multiple outlets to XTSBs * Water seal is required, whether condensate is piped to open drain or returned to humidifier fill cup. XTSB-50 Plastic tie Pitch 2”/ft (15%) minimum Hose clamp (provided) 1½” (DN40) steam hose (provided) Hose clamp (provided) Condensate hose (provided) 7” (178 mm) water seal Plastic tie Maximum recommended distance between humidifier and XTSB is 3 m.
Installation Humidifier wiring All wiring must be in accordance with all governing codes and with the unit wiring diagram. Power supply wiring must be rated for 105 °C. See Figure 19-1 for the humidifier wiring diagram locations d Figure 19-1: Field wiring requirements When selecting a location for installing the humidifier: • Avoid areas close to sources of electromagnetic emissions such as power distribution transformers.
Installation Humidifier wiring WARNING Electric shock hazard Only qualified electrical personnel should perform field wiring installation procedures. Improper wiring or contact with energized circuits may cause property damage, severe personal injury, or death as a result of electric shock and/or fire. Control component placement Follow the guidelines on Page 22 for placing humidistats, transmitters, and airflow proving switches.
Installation Humidifier wiring Earth grounding requirements Proper wiring prevents electrical noise. A safety earth grounding system that meets national, state, and local electrical codes is required. The ground connection must be made with solid metal-to-metal connections. Ground wire should be the same size as power wiring. Electrical noise can produce undesirable effects on electronic control circuits, which affects controllability.
Installation Humidistat and transmitter placement Other factors affecting humidity control Humidistat and sensor locations are critical 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: Humidistat and sensor location have a significant impact on humidifier performance. In most cases, do not interchanging duct and room humidity devices.
Installation Dispersion: Selecting the dispersion assembly location DRI-STEEM humidifiers 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.
Installation Dispersion: Interconnecting piping requirements Important: The steam outlet on the humidifier is sized to the output of the humidifier. DO NOT use steam hose or interconnecting tubing/piping with an inside diameter smaller than the humidifier steam outlet. See note at left. Failure to follow the recommendations in this section can result in excessive back pressure on the humidifier.
Installation Dispersion: Interconnecting piping requirements Connecting to humidifier with tubing or pipe Table 25-2: Hose kit sizing by capacity • See Figures 30-1 and 31-1 for interconnecting tubing and pipe pitch requirements for single tube applications. See Table 33-1 for interconnecting tubing and pipe pitch requirements for Rapid-sorb applications. • Support interconnecting piping between the humidifier steam outlet and the dispersion system with pipe hangers.
Installation Dispersion: Interconnecting piping requirements Figure 26-1: Piping connections to Single dispersion tube, Rapid-sorb, and Ultra-sorb Model LV or LH dispersion assemblies Steam outlet connections to steam hose (XT models 5, 10, 20 shown) Steam outlet connections to tubing or pipe (XT models 30, 50, 75 shown) To dispersion assembly Pitch steam hose 2”/ft (15%) toward dispersion assembly. To dispersion assembly Pitch steam hose 2”/ft (15%) toward dispersion assembly.
Installation Dispersion: Interconnecting piping requirements Figure 27-1: Piping connections to Single dispersion tube, Rapid-sorb, and Ultra-sorb Model LV or LH dispersion assemblies XT-100 To dispersion assembly Pitch steam hose 2”/ft (15%) toward dispersion assembly.
Installation Dispersion: Drip tee installation WARNING Hot surface and steam hazard Dispersion tube, steam hose, tubing, or hard pipe 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.
Installation Dispersion: Single dispersion tube Installation notes • Use DRI-STEEM’s hard pipe adapter kit to connect the steam outlet to hard pipe. Use a hose clamp to connect the steam outlet to steam hose. Use a hose cuff and clamps to connect the steam outlet to tubing. • Thin-walled tubing heats up faster than heavy-walled pipe causing less steam loss at start-up. • Hard pipe or tubing diameter must match XT steam outlet connection.
Installation Dispersion: Single dispersion tube Figure 30-1: Single dispersion tube without condensate drain Duct Steam hose, tubing or pipe (tubing or pipe must be grounded). Insulate tubing and hard pipe to reduce steam loss. Do not insulate steam hose. See Table 24-1 for maximum piping lengths. Single dispersion tube without condensate drain Mounting nut 3/8" - 16 (M10) Pitch* See the first bullet in Installation notes.
Installation Dispersion: Single dispersion tube Figure 31-1: Single dispersion tube with condensate drain Steam hose, tubing, or pipe (tubing or pipe must be grounded). Insulate tubing and hard pipe to reduce steam loss. Do not insulate steam hose. See Table 24-1 for maximum piping lengths. Secure and seal escutcheon plates 90° long sweep or two 45° elbows Single dispersion tube with condensate drain Mounting nut 3/8" - 16 (M10) Pitch* See the first bullet in Installation notes.
Installation Dispersion: Rapid-sorb WARNING Hot surface and steam hazard Dispersion tube, steam hose, tubing, or hard pipe 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 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.
Installation Dispersion: Rapid-sorb Pitch requirements Table 33-2: Rapid-sorb dispersion tube capacities • For Rapid-sorb with the header outside a horizontal-airflow duct, consider the following: – 1½" (DN40) dispersion tubes: Use a fastener of sufficient length to accommodate the 1/8"/ft (1%) pitch requirements toward the ¾" pipe thread (DN20) header drain fitting. – 2" (DN50) dispersion tubes: The bracket can be mounted flush to the ductwork.
Installation Dispersion: Rapid-sorb Figure 34-1: Rapid-sorb in a horizontal airflow with header outside the duct Dashed lines indicate provided by installer. L-bracket. Install with flange facing upstream direction of airflow. Drawing shows L-bracket correctly positioned for airflow. ow Airfl 90° long sweep or two 45° elbows Steam hose, tubing, or pipe (tubing or pipe must be grounded). Insulate tubing and hard pipe to reduce steam loss. Do not insulate steam hose.
Installation Dispersion: Rapid-sorb 4. Position the flange of the L-bracket so it is upstream of the tubes when the assembly is raised and fastened into position. Fasten the L-bracket to the end of the dispersion tubes with the provided bolt, lock washer, and flat washer. Note: See Page 38 for steam supply and condensate drain line connection instructions. 5. Before tightening the L-bracket bolts to the dispersion tubes: • For 1½" (DN40) dispersion tubes: – Dispersion tube will rotate in slip coupling.
Installation Dispersion: Rapid-sorb Figure 36-1: Rapid-sorb in a horizontal airflow with header inside the duct Dashed lines indicate provided by installer. 90° long sweep or two 45° elbows L-bracket. Install with flange facing upstream direction of airflow. Drawing shows L-bracket correctly positioned for airflow. flow Air Duct Dispersion tube. Orient with tubelets perpendicular to airflow. Steam hose, tubing, or pipe (tubing or pipe must be grounded).Insulate tubing and hard pipe to reduce steam loss.
Installation Dispersion: Rapid-sorb 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. Note: See Page 38 for steam supply and condensate drain line connection instructions. • Set slip coupling on header stub or dispersion 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.
Installation Dispersion: Rapid-sorb CAUTION Steam supply connections to Rapid-sorb header Operate Rapid-sorb within rated steam capacity Connect the steam supply interconnecting piping from the humidifier to the Rapid-sorb. The steam supply piping requires a minimum of 1/8"/ft (1%) pitch toward the header. Excessive steam flow 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.
Installation Dispersion: XT steam blowers On a call for humidity, the controller closes the contactors to energize the humidifier electrodes and the fan relay to energize the XT steam blowers (XTSB). When the call for humidity is satisfied, the controller opens the humidifier contactor but keeps the XTSB running for a preset amount of time, which is adjustable via the Vapor-logic4 Setup menu. As steam is discharged from the XTSB, it quickly cools and turns to a visible fog that is lighter than air.
Installation Dispersion: XT steam blowers The XTSB can be mounted on top of an XT humidifier cabinet, or wall-mounted remotely from the humidifier. See Figure 41-2. Figure 40-1: XTSB dimensions XTSB-20 shown XTSB-20, for capacities up to 20 lbs/hr (9.1 kg/h), can be directly mounted on XT humidifier models 5, 10, and 20. Front Side Back E A D C XTSB-50, for capacities up to 50 lbs/hr (22.7 kg/h), can be directly mounted on XT humidifier models 30 and 50.
Installation Dispersion: XT steam blowers Mounting XTSB on top of humidifier The condensate tee kit shipped with the XTSB returns condensate from a top-mounted XTSB to the humidifier's cylinder fill hose. See Figure 41-1. Install the kit as follows: 1. If humidifier is not already mounted to wall, see “Wall mounting humidifier” on Page 10. 2. Remove steam cylinder (see “Removing steam cylinder”on Page 10). 3.
Installation Dispersion: XT steam blowers WARNING Standing water in XTSB Make sure the XTSB is installed plumb. If it is not installed plumb, standing water can accumulate, which can: • cause bacteria and mold growth, which can cause illness; • affect XTSB performance; • cause 212 °F (100 °C) water to discharge from the XTSB, which can cause severe personal injury. Wall mounting XTSB The XTSB is constructed with a pitch toward the drain; however, it must be installed level and plumb for proper drainage.
Installation Dispersion: XT steam blowers Wiring wall-mounted XTSB Make the following wiring connections between the humidifier and the XTSB, and tighten all terminals securely: Figure 43-1: Field-installed hole in fill cup cap for remote XTSB Connect humidifier terminals L1, L2, STM, C, and GRD to matching XTSB terminals L1, L2, STM, C, and GRD. Refer to the external connections diagram shipped with the XTSB.
Installation Supply water considerations Electrode humidifiers function very differently from other humidifier technologies. Some of the factors to consider are steam output consistency, efficiency, cylinder life, and start-up time. Understanding these factors and the variables that impact them will result in proper application of this technology.
Operation Supply water considerations Water conductivity and drain and fill events The paragraphs below explain why steam output consistency, efficiency, cylinder life, and start-up time are impacted by water conductivity and by drain and fill events. Water conductivity: In electrode humidifiers, steam output is directly related to the resistance of the water in the steam cylinder and, therefore, the conductivity of the water between the electrodes.
Operation Principle of operation 1. Controller receives a call for humidity Figure 46-1: XT humidifier principle of operation 4 When the RH level in the humidified space drops below set point, the humidifier controller receives a call for humidity and calculates a corresponding electrical current. The controller closes the contactor, which energizes the electrodes. If there is not enough water in the steam cylinder, the fill valve opens and water enters the steam cylinder. 2.
Operation Components Figure 47-1: XT humidifier components Vapor-logic4 display Vapor-logic4 controls all humidifier functions and can connect to a building automation system via Modbus or optional BACnet MS/TP or LonTalk. See the Vapor-logic4 Installation and Operation Manual for more information.
Operation Start-up procedure XT humidifier and XTSB doors have lift-off hinges for easy removal of open doors. The doors are captivated when closed but should be removed when open. An upward bump could damage the door if it jumps the hinges and falls. WARNING Electric shock hazard Only qualified electrical personnel should perform start-up procedure. After the system is installed and connected properly: 1.
Operation Start-up checklist Your humidification system may not have all of the options listed below. If an item does not apply to your system, skip to the next item and continue the process. ☐ Before you start, read this manual and other information sent with your humidifier. ☐ Verify that the field wiring is done per the instructions in this manual and per the unit wiring diagram. ☐ Do not use demineralized, deionized, or reverse-osmosis water.
Maintenance Maintenance procedures WARNING Electric shock hazard Contact with energized circuits can cause severe personal injury or death as a result of electric shock. To prevent shock, disconnect electrical power before performing service or maintenance procedures on an part of the humidification system. When performing maintenance on the humidifier: • Always switch the keypad control mode to Standby. • Place all power disconnects in OFF position and lock in OFF position.
Maintenance Maintenance procedures 5. Disconnect steam hose: After cylinder and humidifier components have cooled, loosen steam hose clamp and disconnect steam hose from cylinder. 6. Disconnect electrode plugs and high water sensor wire. Note: It is advisable to keep a spare steam cylinder in stock during the humidification season. See “Replacement parts" on Pages 55 and 57 for part numbers. 7. Remove steam cylinder. See “Removing steam cylinder”on Page 10). 8.
Maintenance Maintenance procedures Drain valve Always check the drain valve to determine whether it should be cleaned before installing a new steam cylinder. Typically, the drain valve port is as dirty as the used steam cylinder. Figure 52-1: Drain valve assembly Drain valve body Drain valve coil 1. Remove steam cylinder (see “Removing steam cylinder” on Page 10). 2. Remove the three screws and washers securing drain cup plate to drain cup (see Figure 52-1). 3.
Maintenance Tr o u b l e s h o o t i n g 1. Review possible causes and recommended actions in the Vapor-logic4 Installation and Operation Manual. 2. If you are still having problems, call us. If the Troubleshooting guide does not help you solve the problem, call us with the following information available: • Product name, firmware version, and serial number The product name and serial number are on the nameplate on the right side of the XT humidifier and XTSB.
Maintenance Replacement parts: XT humidifier models 5 through 100 Figure 54-1: XT humidifier models 5 through 100 replacement parts OM-7632 Side subpanel Back subpanel OM-7633 Grounding lug Page 54 • DRI-STEEM XT Electrode Steam Humidifier Installation, Operation, and Maintenance Manual
Maintenance Replacement parts: XT humidifier models 5 through 100 Table 55-1: XT humidifier models 5 through 100 replacement parts Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Description Switch, door interlock Transformer, 208/240/480 to 24 VAC Transformer 277 to 24 VAC Transformer, 600 to 24 VAC Transformer, 230/400 to 24 VAC Contactor - 24 VAC - 35 A Contactor - 24 VAC - 55 A Plug, max.
Maintenance Replacement parts: XT humidifier models 150 and 200 Figure 56-1: XT humidifier models 150 and 200 replacement parts OM-7634 Back subpanel Side subpanel OM-7635 Grounding lug Page 56 • DRI-STEEM XT Electrode Steam Humidifier Installation, Operation, and Maintenance Manual
Maintenance Replacement parts: XT humidifier models 150 and 20 Table 57-1: XT humidifier models 150 and 200 replacement parts Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Description Switch, door interlock Transformer, 208/240/480 to 24 VAC Transformer, 600 to 24 VAC Transformer, 230/400 to 24 VAC Contactor - 24 VAC - 35 A Contactor - 24 VAC - 55 A Plug, max.
Maintenance Replacement parts: Steam blowers XTSB-20 and XTSB-50 Figure 58-1: XTSB-20 and XTSB-50 replacement parts XTSB-50 shown OM-7638 Page 58 • DRI-STEEM XT Electrode Steam Humidifier Installation, Operation, and Maintenance Manual
Maintenance Replacement parts: Steam blowers XTSB-20 and XTSB-50 Table 59-1: XTSB-20 and XTSB-50 replacement parts Item Description Part No. Fan (XTSB-20) 407109-001 Fan (XTSB-50) 306376 2 Breaker, 0.
Warranty Expect quality from the industry leader Two-year Limited Warranty For more than 45 years, DRI-STEEM has been leading the industry with creative and reliable humidification solutions. Our focus on quality is evident in the construction of the XT humidifier. DRI-STEEM leads the industry with a Two-year Limited Warranty and optional extended warranty.