Troubleshooting - Taco i Series Instruction Sheet

In order to prevent heat transmitted through the wall from affecting the sensor reading, it may be necessary to install an insulating
barrier behind the enclosure.
The sensor should be mounted on a wall which best represents the heat load on the building (a northern wall for most buildings and
a southern facing wall for buildings with large south facing glass areas). The sensor should not be exposed to heat sources such as
ventilation or window openings. The sensor should be installed at an elevation above the ground that will prevent tampering.
Connect 18 AWG or similar wire from the outdoor sensor directly into the SENSOR COMMON and OUTDOOR terminals on the
iSeries-R. Replace the front cover of the sensor enclosure.
System Supply and Boiler Return Sensors
The sensors can be strapped directly to the pipe using a cable tie. Insulation should be placed around the sensor to reduce the effect of
air currents on the sensor measurement. The sensors should be placed downstream of a pump or after an elbow or similar fitting. This
is especially important if large diameter pipes are used because the thermal stratification within the pipe can result in erroneous sensor
readings. Proper sensor location requires that the fluid is thoroughly mixed within the pipe before it reaches the sensor.
If the System Supply Sensor is used to measure duct temperature, the sensor should be mounted in such manner that it measures the
average duct outlet temperature.
System Supply Sensor
Connect the two wires from the supply sensor directly into the SENSOR COMMON and SUPPLY terminals on the iSeries-R.
Boiler Return Sensor
Connect the two wires from the boiler return sensor directly into the SENSOR COMMON and BOILER terminals on the iSeries-R.

Troubleshooting

As in any troubleshooting procedure, it is important to isolate a problem as much as possible before proceeding. The error messages
greatly simplify troubleshooting of the iSeries-R. When the control flashes an error message, identify the fault and follow standard test-
ing procedures to confirm the problem. If you suspect a wiring fault, return to the wiring section on this brochure and carefully check all
external wiring and wiring connections.
Multi-Status LED
Adjustment of Settings
- If the outdoor temperature is cold and the building is cold, increase the Reset Ratio setting by one notch per day.
Testing the Sensors
A good quality test meter capable of measuring up to 5000 kΩ (1 kΩ = 1000 Ω) is required to measure the sensor resistance. In addition
to this, the actual temperature must be measured with a good quality digital thermometer.
First measure the temperature using the thermometer and then measure the resistance of the sensor at the iSeries-R. The wires from
the sensor must not be connected to the iSeries-R while the test is performed. The wiring terminals are easily removed by pulling them
from the iSeries-R. Using the chart below, estimate the temperature measured by the sensor. The sensor and thermometer readings
should be close. If the test meter reads a very high resistance, there may be a broken wire, a poor wiring connection or a defective
sensor. If the resistance is very low, the wiring may be shorted, there may be moisture in the sensor or the sensor may be defective.
To test for a defective sensor, measure the resistance directly at the sensor location.
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