User Manual

ManualsBrandsSiemens ManualsSensors TemperatureCE Declaration QFA81 / QFA81.1

Siemens Building Technologies CM1N1513E / 02.1999

Landis & Staefa Division 1/4

513

Room Hygrostats QFA81...

for relative humidity

QFA81.1 QFA81

On/off hygrostat with microswitch,

with humidity sensor,

with plastic texture sensing strip (good linearity, wide measuring range),

for the control of humidification equipment,

for the control of dehumidification equipment,

for direct wall mounting or mounting on recessed conduit boxes

The hygrostats are designed for controlling and monitoring the relative humidity in venti-

lating and air conditioning plants.

They control the humidity content of the room air within an adjustable range of 30 to

100 % r.h.

They can also be used for monitoring a minimum or maximum humidity level.

Type reference Setpoint range (W

)

Switching

differential (X

)

Setpoint

adjustment

QFA81 30…100 % r.h.

approx. 4 % r.h.

externally

QFA81.1 30…100 % r.h.

approx. 4 % r.h.

internally

When ordering, please give name and type reference; for example:

room hygrostat QFA81

The hygrostat acquires the relative humidity of the room air with its plastic texture sens-

ing strip. The strip actuates a microswitch with a fixed switching differential X

and a

potential-free contact output (S.P.D.T.), depending on the relative humidity of the air. If

the actual humidity deviates from the adjusted setpoint, the hygrostat switches the as-

sociated humidification or dehumidification equipment on or off as shown in the following

function diagram.

Use

Type summary

Ordering

Mode of operation

Summary of content (4 pages)

PAGE 1
Room Hygrostats 513 QFA81... for relative humidity QFA81.1 QFA81 On / off hygrostat with microswitch, with humidity sensor, with plastic texture sensing strip (good linearity, wide measuring range), for the control of humidification equipment, for the control of dehumidification equipment, for direct wall mounting or mounting on recessed conduit boxes Use The hygrostats are designed for controlling and monitoring the relative humidity in ventilating and air conditioning plants.
PAGE 2
r. h. [%] x 1513D01E Function diagram Xd w t S1 1 4 t 2 r.h. S1 w x Xd Relative humidity in % Microswitch 1−2 Humidification 1−4 Dehumidification Setpoint Actual value Switching differential If the relative humidity exceeds the adjusted setpoint, the potential-free contact of the microswitch will change over from 1−2 to 1−4. If the relative humidity falls by the amount of the fixed switching differential Xd, the contact will return to the position 1−2.
PAGE 3
Mounting notes Mounting location The hygrostat should be mounted on an inner wall approximately 1.5 m above the floor and at least 0.5 m from the next wall. At the location where the unit is mounted, there should be a natural circulation of room air (no draughts, no corners of the room, not behind curtains, not too close to doors and windows, and not on an outer wall).
PAGE 4
1 ϕ 2 1513G01 Internal diagram 4 1−2 1−4 Humidification Dehumidification % rH 74 3,2 Dimensions 70 50 100 60 90 80 24 60 1513M01 40 30 74 Drilling template for wall mounting Dimensions in mm CM1N1513E / 02.1999 4/4  1999 Siemens Building Technologies Ltd.