Bosch Worcester Greenstar HIU E Installation And Maintenance Instructions Manual page 3

8.4 Differential pressure control valve . . . . . . . . . . . . . . . . 55
8.5 Circulating pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
8.6 Heat meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
8.7 Expansion vessel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
8.8 Domestic hot water NTC sensor and safety valve . . . . 56
8.9 Flow turbine, flow regulator assembly and filter . . . . . 57
8.10 Summer by-pass (if fitted) . . . . . . . . . . . . . . . . . . . . . . 57
8.11 District and central heating NTC sensors . . . . . . . . . . . 57
8.12 Control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
9 Fault finding and diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . 59
9.1 Central heating trouble shooting guide . . . . . . . . . . . . 59
9.2 Domestic hot water trouble shooting guide . . . . . . . . . 60
9.3 HIU Control unit LED indications . . . . . . . . . . . . . . . . . 61
9.4 Control valve fault indication . . . . . . . . . . . . . . . . . . . . 62
9.4.1 Action of control valve during an error . . . . . . . . . . . . . 62
9.4.2 Control valve calibration . . . . . . . . . . . . . . . . . . . . . . . . 62
9.5 Circulating pump fault indication . . . . . . . . . . . . . . . . . 62
9.6 Sense II (EMS controller) Diagnosis menu . . . . . . . . . . 63
9.6.1 Operating the service menu . . . . . . . . . . . . . . . . . . . . . 63
9.6.2 Heat Interface Unit diagnosis menu . . . . . . . . . . . . . . . 63
9.6.3 Heat Interface Unit diagnosis functions . . . . . . . . . . . . 63
9.6.4 Heat Interface Unit function test menu . . . . . . . . . . . . . 64
9.7 Central heating pump test . . . . . . . . . . . . . . . . . . . . . . . 64
9.8 Heat meter (if fitted) . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
9.9 Component resistance characteristics . . . . . . . . . . . . . 64
9.9.1 Flow/return temperature NTC sensors . . . . . . . . . . . . . 64
9.9.2 DHW NTC wet sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
9.9.3 Outdoor weather compensation sensor . . . . . . . . . . . . 64
6 720 808 928 (2017/06)
Contents
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