Ideal Heating i305 Installation & Servicing page 49

Display
f8
HOT WATER
PREHEAT
OFF
F9
HOT WATER
PREHEAT
OFF
L9
HOT WATER
PREHEAT
OFF
fp
HOT WATER
PREHEAT
OFF
fc
HOT WATER
PREHEAT
OFF
F
HOT WATER
PREHEAT
OFF
Installation and Servicing
SECTION 4 - FAULT FINDING
Fault
Remove harness to primary return thermistor and using a multi-meter
measure the resistance of the thermistor – This should be around 10kΩ in
Primary Thermistor
ambient conditions. If thermistor is functioning correctly reconnect harness
Fault
to flow thermistor and reset unit. If thermistor is not functioning correctly
replace item. If fault persists, replace PCB (see Section 3.20).
PCB Fault Replace PCB using the process as shown in Section 3.20.
PCB Fault Replace PCB using the process as shown in Section 3.20.
Check system water pressure is between 1 and 1.5 bar on the system
pressure gauge. If system pressure is low increase the pressure using the
Pump Failure
filling loop (see Section 2.5). Check system for blockages and flush system if
necessary. If fault persists, replace pump (see Section 3.10).
Remove harness to DHW thermistor and using a multi-meter measure
the resistance of the thermistor – This should be around 10kΩ in ambient
DHW Thermistor
conditions. If thermistor is functioning correctly reconnect harness to flow
Fault
thermistor and reset unit. If thermistor is not functioning correctly replace
item. If fault persists, replace PCB (see Section 3.20).
OpenTherm Plus Check connection between smart thermostat and HIU. Refer to Smart
thermostat manual fault finding.
Fault
Action
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