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Series 8900SH Control Panel Operation And Installation Manual
Section 4 Sensor Calibration
SECTION 4: SENSOR CALIBRATION
This section will deal with the calibration of the sensors that measure both outside air
temperatures and water system temperatures. Correct calibration is very important so the
control panel receives the accurate information necessary to properly control the building
temperature.
The TRIAD system uses a minimum of two sensors, one which is placed outside, on the north
or northwest side of a building, and the second which is placed in the Return Water Line
coming back to the boilers.
The panel moniters temperature by passing a very weak electrical current through the sensor
and back to the control panel. The resistance to this current changes when the temperature
around the sensor changes, which is interpreted by the panel as an increase or decrease in
temperature.
CALIBRATION:
To calibrate the sensors you will need an accurate digital thermometer, a small non-magnetic
flat screwdriver, a medium non-magnetic flat screwdriver, and a small crescent wrench.
PLEASE NOTE THAT THE SERIES 8900SH CONTROL PANEL MUST BE TURNED ON FOR AT
LEAST 15 MINUTES BEFORE ATTEMPTING TO CALIBRATE THE SENSORS.
Press the function CODE for the sensor to display the current reading.
CODE xx = Potentiometer # = Sensor #
CODE 11 = R26 = Outdoor Sensor = S1
CODE 12 = R27 = Return Temp. Sensor = S3
Take off the cover of the main circuit board by loosening the two screws on either side of the
cover and pulling it straight off.
The sensors should be wired up to the sensor terminal strip. If they are not, skip to
“Troubleshoooting The Sensors” in Section 5.
Then, locate the outside sensor and take a reading with your digital thermometer as close as
possible to the sensor. Now, go directly back to the control panel and enter 11. The display
light will indicate what the panel thinks is the temperature at the outside sensor; (S1). Carefully