Product Overview

Technical Instructions TH 134 Pneumatic High and Low Temperature Detection Thermostats
Document Number 155-063P25
April 1, 2005
Page 2 Siemens Industry, Inc.
Warning/Caution Notations
WARNING:
Personal injury/loss of life may occur if a
procedure is not performed as specified.
CAUTION:
Equipment damage, or loss of data may occur if
the user does not follow procedure as specified.
Application
The pneumatic high and low temperature detection thermostats are used on pneumatic
heating, cooling and air conditioning systems. These thermostats must be used in areas
protected from the weather.
On a typical high temperature sensing application the thermostat shuts down air
conditioning or ventilating fans when the duct temperature becomes excessively high.
The low temperature detection thermostat stops a fan or closes a damper when the
temperature at any one-foot or greater section of the sensing element drops to or below
the set point.
WARNING:
The pneumatic high and low temperature detection thermostats are designed
for use only as operating controls. Where an operating control failure would
result in personal injury and/or loss of property, it is the responsibility of the
installer to add devices (safety, limit controls) or systems (alarm, supervisory
systems) that protect against, or warn of control failure.
Piping Diagrams
Figure 1. Mixed Air Low Temperature Detection.
Figure 2. Mixed Air Low Temperature Detection.
Figure 3. Discharge Air High Temperature Detection.
Figure 4. Return Air High Temperature Detection.