M thermal Mono
202004 83
Procedure
Water side heat exchanger water inlet /
outlet temperature sensor is loose
1
Ensure the temperature sensor is
connected properly
Water side heat exchanger water inlet /
outlet temperature sensor has
short-circuited or failed
2
Replace the temperature sensor
Water piping contains air
Purge air from the water system
The water flow rate is not sufficient,
caused by crushed or bent water piping,
incorrect pump speed setting, high
resistance in water piping or broken
expansion vessel
Inspect the system and fix the error
Notes:
1. Water side heat exchanger water inlet temperature sensor and water side heat exchanger water outlet temperature sensor connections are port CN6 on
the hydronic system main PCB (labeled 8 in Figure 4-2.1 in Part 4, 2.2 “Main PCB for Hydronic System”).
2. Measure sensor resistance. If the resistance is too low, the sensor has short-circuited. If the resistance is not consistent with the sensor’s resistance
characteristics table, the sensor has failed. Refer to Part 2, 1 “Layout of Functional Components” and to Table 5-5.3 in Part 5, 5.1 “Temperature Sensor
Resistance Characteristics”.