Product Overview

Technical Instruction

Document No. 155-067P25

Rev. 1, July, 1999

Page 8 Siemens Building Technologies, Inc.

Landis Division

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The changeover point is factory set to occur between 19 and 22 psi (131 and 152 kPa).

The changeover point can be field adjustable to occur between 14 and 22 psi (96 and

152 kPa).

Connect pressure gauge or manometer to measure supply pressure to thermostat.

Use 30 psi (207 kPa) supply through a positioning switch so pressure can be fully

variable.

Determine current change over point. Turn day dial so day and night control

pressures are different. Then note the changeover point on the control gauge as the

supply pressure changes.

Remove thermometer for access to changeover adjust screw. Use a 1/16’ Allen Hex

Key to adjust changeover adjust screw as follows:

If changeover is too high, turn off supply pressure and rotate changeover adjust

screw clockwise. One turn decreases changeover point by about 3 psi (20 kPa).

Turn on supply pressure and recheck to verify new changeover point.

If changeover is too low, turn off supply pressure and rotate changeover adjust

screw counterclockwise. One turn increases changeover point by about 3 psi (20

kPa). Turn on supply pressure and recheck to verify new changeover point.

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