Logic For The 535 Se/Ld Rdb Control Box - Bosch Worcester Greenstar Danesmoor 12/18 Installation, Commissioning And Servicing Instruction Manual

Boiler not
operating
with a
heating I
hot water
demand
Burner
motor runs?
No
t
Yes ...
Replace
control box
•
Yes
Lockout
within 1
second?
No ...
Replace
electrodes/
f.-
No
leads
lockout
after 12 sec Yes ...
purge?
No
t
Replace
control baK
•
Yes
Eectrodes &
leads OK?
...
No
Ignition
spark
proved?
Unblock or
replace pipe .,_ No
Pump
Yes ... produces
Yes
pressure?
No
t
Replace
nozzle
*
Yes
Pipe to
nozzle
holder OK?
•
No
Nozzle
atomlslng
fuel?
Yes
-Yes
Reset air
setting
•
No
Combustion
air setting
correct?
230Vto
control box?
r
No ....
Check boller
controls &
supply
Motor gives
50 Volts on
No...,
Replace
motor
Purge
pressure
Solen old operating?
-Yes...., Increase the pump pressure.
whttewire7
1-2 bar?
Pressure now OK 7
Motor400
between bkle&
No ...,
black wires 1
Yes
f
Replace
control box
Replace
motor/pump
Replace
motor
Yes
f
Solenoid coil
functional
(1000)?
Yes
f
Photocell
functional?
No
t
Replace
photocell
No
t
Replace
Drive
-No•
coupling
solenoid coil
broken?
No
f
-·-§
es alf1trolbCIK
Oil to pump?
Yes
f
Replace oil
pump
No
t
Solenoid coil
functional
(1000)7
'
No
f
Replace
solenoid coil
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 1 OMO or open circuit) in the dark and low resistance (3k0 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.
Yes ...
Solenoid
lead OK?
Yes
f
Replace
pump stem
valve,
pressure
OK?
No
t
Replace
control box
Yes ...
Reset
combustion
head
...
No
Combustion
head set
correctly?
Yes
t
Flame off&
re-lights?
Yes
f
If BF
remove
burner
snorkle tube
&
retest.
Burner OK?
No
f
Photo cell
functional?
No
t
Replace
photocell
-No...,
Yes ...
Yes
MEASUREA~~230V
TESTS BETWEEN
NEIJTRAL (NJ AND TliE
PIN, WIRE OR TERMINAL
SPECIFIED.
Boiler or flue
blocked
Reseal BF
or reposition
terminal
Replace
control baK
6720808218-411 . 1Wo