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8.0 Troubleshooting
This section includes various conditions as well as possible solutions. Often, a problem can be
identified and solved through basic checks: confirming the electrical power supply, gas flow and
resetting the thermostat control. Below are some common troubleshooting issues including fixes.
8.1 Electronic components
This section details the method for troubleshooting the non-standard electronic components on the
boiler.
8.1.1 Temperature sensors
The resistance of the temperature sensors varies inversely with temperature. To test, measure the
temperature of the sensed environment and compare with the value derived from the measurement
of the resistance (obtained by connecting a good quality test meter capable of measuring up to 5,000
kΩ (5,000,000Ω) at the controller end of the sensor lead).
To obtain a resistance reading, remove power to the boiler. For the supply water, return water,
DHW inlet, DHW outlet, and vent temperature sensors, remove the wire leads by disconnecting their
respective Molex connectors. Place multi-meter probes into the sensor’s female Molex connector
socket. Do not apply voltage to the sensor as damage may result.
The supply water and vent temperature sensors each contain two separate circuits. Test each pair.
Both circuits must deliver accurate (although not necessarily identical) readings. Note that failures
may occur only within certain temperature ranges.
Summary of Contents for CX Series
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Page 114: ...Appendices Wiring diagrams Figure 48 Controller electrical diagram 114 Section Troubleshooting...
Page 115: ...Figure 49 Internal wiring diagram 115 Wiring diagrams...
Page 116: ...Figure 50 Sequence of Operation 116 Section Troubleshooting...