Spheros thermo 231, Workshop Manual

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5 Troubleshooting Thermo 230 / 231 / 300 / 301 / 350
504
5.3.2 Fault Symptoms
5.3.2.1 Fault Symptom "No Start"
NOTE
Heaters with control unit 1572D:
If the heater performs 8 consecutive attempts to start due
to a malfunction, the heater enters an error lockout and
stops any further attempts to start. This error lockout is
superior to the normal error lockout condition.
The error lockout reset is achieved by switching the heater
on and disconnection of the heater power supply during
run-down.
Switch on heater.
Is combustion air fan
operating? Motor and fan wheel
free to move? Is fan wheel caught
in cap? Is voltage present on
plug contact A3? Check fuses F1/F2/F3
and relais K1, K2 and
replace as required
(control unit 1572
only).
Does trouble persist?
Check motor electrics
and replace as
required. Replace cap
and fan wheel. Is voltage too low?
Rated value >20,5 volts
(± 0,5 volts) Check electrical
wiring and
connections.
Does trouble persist?
Low voltage switch
off during start-up.
Check battery. Control unit defective,
replace.
Is fuel free of bubbles
in supply and return? Is fuel filter
contaminated? Fuel suction line
leak? Fuel lines empty? Are O-rings in fuel
pump?
Is pump mounted
securely?
Replace fuel filter. Retighten line
connections,
replace lines as
required. Repeat start (several
times if necessary)
until lines are filled. Fuel pump defective,
replace.
Is solenoid valve
connected to
electrics? Connect solenoid
valve.
Is gap between igniter
electrodes ok? Check gap between
igniter electrodes.
Is nozzle free of foreign
matter and deposits
and properly secured? Replace nozzle.
YES
NO
Is viewing glass of
flame sensor
contaminated? Clean window and
viewing glass.