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Thermo-Hygrograph

Operating Instructions 

Thermo-Hygrograph (252)

Enclosure: Operating Instructions “Drum Recorders“

Thermo-Hygrograph  (252) 

  

Operating Instructions

1 General

Thermo-Hygrographs are used to measure and record air 

temperature and relative humidity (r.h.). The measured values 

are recorded, using drum recorders driven by clockworks. 

These rugged and reliable precision products have been 

proven over decades of use in business, science and culture 

around the world. They are suited for service in industry and 

private environments. To take advantage of the high measur-

ing accuracy and to maintain them for many years in service, 

please observe our following recommendations. 

Place of installation

Install the instrument horizontally in a vibration-free location. 

Depending on the model, the permissible ambient tempera-

ture varies between -35...+80 °C. The instrument should be 

protected against direct heat radiation and conduction. For 

outdoor installation, a protection screen against radiation and 

precipitation is required.

Setting into operation

To open the instrument, gently push down the hood 

2

, pull 

the locking knob 

and swing up the hood. At the same time 

hold the styrofoam cushion 

22

 (located under the cover) and 

remove it after opening the instrument.

3.1 

Removing the transport lock

Loosen the recording arm‘s transport lock 

by turning it on the 

lifting rod 

by about 90°. Remove the cardboard wedge at the 

switch-off lever 

and save it. Carefully remove the protective 

cap from the felt-tipped pen 

and save it.

3.2 

Mounting the humidity measuring  

 element

Take the humidity measuring element N out of its separate 

packing. Put the measuring element‘s mount 

provided with 

two bore holes into the upper hooks. Put the lower mount 

into the lower hook. At the same time lift the recording arm 

10

regenerate the humidity measuring element N as described 

under 6. The humidity measuring element K is already mount-

ed and is maintenance-free.

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