Fault Finding Logic For Riello Control Box - Worcester GREENSTAR UTILITY 18/25 Instruction Manual

FAULT FINDING
& DIAGRAMS
MO535 IMPORTANT NOTE: The box has a built in delay of 11 seconds before activating the motor.
The preheater link must be fitted at
Boiler not
operating
with a
heating /
hot water
demand Replace
Replace
electrodes/
control box
leads
Yes
Lockout Lockout
Burner
Yes within 1 NO after 12 sec
motor runs?
second? purge?
No
No
Check boiler Motor gives
L & N to
controls & 50 Volts on
No
control box?
supply white wire?
Yes Yes
Motor or
Solenoid coil
Replace
pump Yes
functional
motor/pump
seized? (100Ω)?
No Yes
Motor 40Ω
Replace Photo cell
between blue &
No
motor functional?
black wires ?
No
Yes
Replace Replace
control box photo cell
All resistance measurements are actual measured values and some variation is to be expected, therefore measured
values should be similar to but not necessarily identical to the given values.
The operation of the photo cell can be tested by measuring the resistance across the photo cell, it should be a high
resistance (greater than 10MΩ or open circuit) in the dark and low resistance (3kΩ or less) in light.
Burners on balanced flue systems can recirculate flue products resulting in the burner cycling, if this happens check the
flue system integrity and the terminal position.
for the box to operate
A
Replace
control box
Yes
Eectrodes & Unblock or
No No
leads OK?
replace pipe
holder OK?
No
Ignition Pump
Yes
Yes spark Yes produces
proved? pressure?
No
Purge
Replace
No pressure Yes
motor
pressure, pressure OK?
1-2 bar?
No
Drive Solenoid coil
Replace
No
coupling
solenoid coil
broken?
No
Replace
Yes Oil to pump?
control box solenoid coil
Yes
Replace oil
pump
Replace
nozzle
Yes
Pipe to
Reset Reset
nozzle
air combustion
setting setting
No No No
Nozzle Combustion Combustion
Yes
atomising Yes air setting head set
fuel? correct? correctly?
Yes
Yes
Solenoid operating?
Flame off &
Increase the pump
re-lights?
No Yes
If BF
Coil lead
Remove
Yes
functional
OK?
burner
(100Ω)?
snorkel tube
Yes
No & retest.
Lights OK?
No
Replace
Replace
pump stem
valve,
Photo cell
pressure
functional?
OK?
No
No
Replace Replace
control box photo cell
Boiler or flue
No
blocked
Reseal BF
or reposition
Yes
terminal
Replace
Yes
control box
Measure all 230V tests between
Neutral (N) and the pin, wire or
terminal specified.