ICI Caldaie RIO 140 Installation And Servicing Manual - page 38
12 FAULT
FINDING
38
During the fault finding procedure the first electrical checks to be carried out are:- Short circuit, Polarity, Earth
continuity and Resistance to earth. After completing a service or fault finding task which has required the
breaking and remaking of electrical connections, the electrical checks must be repeated.
Preliminary check of mains voltage and switches – ensure timer is in an ‘on’ position and room
thermostat (it fitted) is calling for heat.
BURNER WILL NOT LIGHT
Pump and fan not operating (but no lock-out)
Possible cause
Blown fuse on driver board
Seized pump
Airlock in pump/boiler
No power to pump
Faulty pump
Faulty driver board
Remedy
Check fuse, replace if necessary
Check pump, free rotor or replace if necessary
Vent pump and boiler
Check electrical connections
Check 230V at pump, replace if necessary
Check 230V at board, replace if necessary
Pump operating, fan not operating (but no lock-out)
Possible cause
No power to ignition control unit
Primary water flow switch not activated
Primary water flow switch faulty
No power to fan
Fan faulty
Air pressure switch faulty
Ignition control PCB faulty
Remedy
Check 230V output from driver board (pins 3 & 4 to left of
fuse)
Check connections from driver board
Check operation of primary flow switch
Check switch continuity, replace if necessary
Check 230V output from ignition board (pins 8 & 9 on
ignition PCB)
Check electrical connections to fan
Check continuity of wiring to fan
Check 230V at fan, replace fan if necessary
Check electrical connections to switch
Check continuity (N/C contact), replace if necessary
Check control, replace if necessary
Pump and fan operating followed by boiler lock-out
Possible cause
Air pressure switch faulty
Blocked air pressure switch tubes
Air switch tubes incorrectly connected
Flue system blocked or obstructed
Fan venturi blocked
Overheat thermostat contacts open
No gas at burner
No electrical supply to gas valve
Gas valve faulty
No spark at electrode (but gas valve heard to
operate)
Ignition control PCB faulty
Remedy
Check electrical connections to switch
Check continuity (N/O contact), replace if necessary
Check and rectify as necessary
Check and rectify as necessary
Check and rectify as necessary
Check and rectify as necessary
If boiler is hot, allow to cool and re-check
Check switch continuity, replace if necessary
Check gas service cock is open
Check cock at meter is open
Check for gas pressure at burner test point
Check ignition control is correctly fitted on gas valve
Check valve, replace if necessary
Check ignition lead connections, rectify as necessary
Check ignition lead continuity, replace if necessary
Check electrode setting and rectify as necessary
Check earthing electrode and rectify as necessary
Check control, replace if necessary