Installation Instructions Document No. 129-606 July 15, 2010 QFM81.2, QFM81.21 Duct Hygrostats Item Number 129-606, Rev. AA Page 1 of 2 Product Description These instructions explain how to install a QFM81.2 or QFM81.21 Duct Hygrostat. Product Numbers QFM81.2 Duct Hygrostat with external setpoint QFM81.21 Duct Hygrostat Required Tools • Screwdriver • Electric drill • 7 mm Wrench Expected Installation Time 15 minutes Installation Air Duct Mounting If the duct hygrostat is used for control, mount in the exhaust air duct after the room to be controlled. If the duct hygrostat is used for monitoring the maximum or minimum humidity level, mount in the supply air duct. Mounting Positions The immersion sensor stem must be mounted either horizontally or vertically with the stem pointing downward. Do not mount with the stem pointing upward. (See Figure 1.) SEN0508R1 Figure 1. Acceptable Mounting Positions. Ensure that the air to be measured is sufficiently mixed at the point of measurement for accurate humidity measurements. The mounting orientation is dependent on the air velocity in the ductwork: at <5 m/s, the holes in the stem must face the airflow; at >5 m/s, they must be perpendicular to the direction of airflow. (See Figure 2.) SEN0509R1 < 5 m /s > 5m /s Figure 2. Mounting Orientations. Minimum Immersion Length NOTE: When mounting the hygrostat in air ducts, the minimum immersion length of the stem is 5.12 inches (130 mm). The mounting flange supplied with the unit allows the immersion length to be adjusted between 5.12 inches (130 mm) and 6.14 inches (156 mm). Figure 3. Mounting Flange. Document No. 129-606 Installation Instructions July 15, 2010 Calibration Wall Mounting The hygrostat should be mounted: If humidity is known and field calibration is needed, then the device may be set to known humidity. Use a 7 mm wrench to adjust until an audible click is heard. This will calibrate the unit. • on an inner wall approximately 4.9 feet (1.5 m) above the floor, and at least 1.6 feet (0.5 m) from the closest adjoining wall. • where there is a natural circulation of room air (do not mount near drafts, in corners, behind curtains, too close to doors and windows, or on an outer wall). • away from sources of heat and refrigeration (radiators, computers, televisions, concealed heating pipes, hot or cold water pipes). • where it is not exposed to direct sunlight. NOTE: You must use the mounting flange supplied with the hygrostat for wall mounting. Wiring 1. Using a flat-blade screw driver, loosen the mounting screw and remove the cover to expose the wiring terminals. Figure 5. Humidity Calibration. Replace the cover and tighten the mounting screw with a flat-blade screwdriver. 2. Wire the device as required. See Figure 4. The installation is now complete. SEN0510R1 1 23 1 – 2 Humidification 1 – 3 Dehumidification Figure 4. Wiring Connections. Information in this publication is based on current specifications. The company reserves the right to make changes in specifications and models as design improvements are introduced. Product or company names mentioned herein may be the trademarks of their respective owners. © 2010 Siemens Industry, Inc. Siemens Industry, Inc. Building Technologies Division 1000 Deerfield Parkway Buffalo Grove, IL 60089-4513 U.S.A. Your feedback is important to us. If you have comments about this document, please send them to SBT_technical.editor.us.sbt@siemens.com Document No. 129-606 Printed in the USA Page 2 of 2 Next >