Wellea Monobloc
77
Notes:
1.
Discharge pipe temperature sensor connection is port CN8 on the refrigerant system main PCBs (labeled 11 in Figure 4-2.2 in Part 4, 2.3 “Main PCBs for
Refrigerant System, Inverter Modules and Filter Boards”, (labeled 4 in Figures 4-2.4 in Prat 4, 2.3“Main PCBs for Refrigerant System, Inverter Modules and
Filter Boards” and labelled 5 in Figure 4-2.6 in Part 4, 2.3 “Main PCBs for Refrigerant System, Inverter Modules and Filter Boards”).
2.
Backup electric heater water outlet 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”). Domestic hot water tank temperature sensor
connection is port CN13 on the hydronic system main PCB (labeled 9 in Figure 4-2.1 in Part 4, 2.2 “Main PCB for Hydronic System”).
3.
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 5-5.1 or 5-5.2 in Part 5, 5.1 “Temperature
Sensor Resistance Characteristics”.
4.
High pressure switch connection is port CN13 on the MHC-V5(7,9)W/D2N8 refrigerant system main PCB (labeled 10 in Figure 4-2.2 in Part 4, 2.3 “Main
PCBs for Refrigerant System, Inverter Modules and Filter Boards” ), port CN9 on the MHC-V12(14, 16)W/D2N8 outdoor unit invert module PCB (labeled 2
in Figure 4-2.5 in Part 4, 2.3 “Main PCBs for Refrigerant System, Inverter Modules and Filter Boards” ) and port CN9 on the MHC-V12(14, 16)W/D2RN8
outdoor unit invert module PCB (labeled 8 in Figure 4-2.6 in Part 4, 2.3 “Main PCBs for Refrigerant System, Inverter Modules and Filter Boards”). Pressure
sensor connection is port CN4 on the MHC-V5(7,9)W/D2N8 refrigerant system main PCB (labeled 15 in Figure 4-2.2 in Part 4, 2.3 “Main PCBs for
Refrigerant System, Inverter Modules and Filter Boards” ), port CN28 on the MHC-V12(14, 16)W/D2N8 refrigerant system main PCB (labeled 3 in Figure
4-2.4 in Part 4, 2.3 “Main PCBs for Refrigerant System, Inverter Modules and Filter Boards” ) and port CN36 on the MHC-V12(14, 16)W/D2RN8 refrigerant
system main PCB (labeled 3 in Figure 4-2.6 in Part 4, 2.3 “Main PCBs for Refrigerant System, Inverter Modules and Filter Boards”).
5.
Measure the resistance among the three terminals of the pressure sensor. If the resistance is of the order of mega Ohms or infinite, the pressure sensor
has failed.
6.
High pressure side blockage causes discharge temperature to be higher than normal, discharge pressure to be higher than normal and suction pressure to
be lower than normal.
7.
Check air side heat exchanger, fan(s) and air outlets for dirt/blockages.
8.
Check the water side heat exchanger, water piping, circulator pumps and water flow switch for dirt/blockages.
