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QFA1000, QFA1001 

Technical Instructions

Document No. 155-708

July 19, 2010

 

Room Hygrostats 

 

QFA1001 

 

QFA1000

 

 

Siemens Industry, Inc. 

Description 

The room hygrostats are used for controlling and monitoring relative humidity in 
ventilation or air conditioning facilities. They ensure room humidity control within the 
selectable range of 30 to 90% relative humidity by controlling humidification or 
dehumidification equipment. They can also be used for monitoring minimum or 
maximum humidity levels. 

Features 

  Hygrostat with single-pole microswitch 

  Humidity measuring element made of stabilized plastic 

  Setpoint knob for the upper switching point 

  Mounts directly on the wall or on a recessed conduit box 

Application 

  For controlling humidification equipment 

  For controlling dehumidification equipment 

Product Numbers 

 

Switching Differential

1

Product 
Number 

Setpoint Setting 

Range 

Statically Dynamically 

Setpoint 

Adjustment 

QFA1000 Internally 

QFA1001 

30 to 90% rh 

Approx. 4% rh 

6% rh 

Externally 

1)

  The static switching differential is determined at a constant ambient humidity by 

turning the setting knob. 

 

The dynamic switching differential is determined by changing the ambient humidity 
while maintaining the same setpoint adjustment; only the dynamic switching 
differential is of practical value. 

 

 

 

Summary of Contents for QFA1000

Page 1: ...midity measuring element made of stabilized plastic Setpoint knob for the upper switching point Mounts directly on the wall or on a recessed conduit box Application For controlling humidification equipment For controlling dehumidification equipment Product Numbers Switching Differential 1 Product Number Setpoint Setting Range Statically Dynamically Setpoint Adjustment QFA1000 Internally QFA1001 30...

Page 2: ...g effect the switching point drifts slowly and constantly For this reason recalibration may be required in due time At temperatures other than the calibration temperature the switching point drifts systematically temperature influence Also in the case of fast humidity changes the switching point will temporarily be shifted Mechanical Design QFA1001 The room hygrostat is designed for wall mounting ...

Page 3: ...all Sources of heat and refrigeration radiators computers televisions concealed heating pipes hot or cold water pipes must be at an adequate distance The hygrostat should not be exposed to direct sunlight Mounting Instructions Installation Instructions for the room hygrostat are available online Specifications Functional data Setpoint range 30 to 90 rh Temperature operating range 32 F to 122 F 0 C...

Page 4: ...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 Materials and colors Base PPS Fortron fiberglass reinforced Black Cover PC Lexan 940 pure white Humidity measuring element Plastic Standards conformity EMC directive 89 336 EEC UL UL873 cUL Canadian Standard C22 2 No 24 93 Weight QFA1001 3 17 oun...

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