5.2
FAULT FINDING FLOW CHART
WD51/2/1997 Chapter 5 : Fault FindingThe Keston 170 Condensing Boiler
Installation & Servicing Instructions
Page : 26
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Continued on sheet 2
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Is amber switch light on?
Is there 230V between
terminals SL & N?
Is the boiler switched on?
Faulty Switch Neon
-Replace.
Switch On Boiler.
Check External Controls.
Apply Power To Boiler.
Is the boiler thermostat closed?
Is there 230V between control
box pins 10 & 2 and between
pins 10 and 1?
Is the air pressure switch stuck
in the NO position?
Is there 230V between control
box pins 6 & neutral?
Is there continuity between live
supply from relay to blower &
Neutral through motor
resistance?
Is the f an running?
Is motor overload tripped?
Is there wiring continuity
& in-line connector
to motor?
Boiler return is too hot. Allow
to cool. OR faulty thermostat -
Replce.
Check continuity (see section
5.3)
Faulty pipe connections to Air
Press. Switch. OR Faulty Air
Press. Switch - Replace.
Control box faulty.
Motor/Fan fault y - Replace.
Wait for motor to cool.
Identify & correct break.
START
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Is the motor relay operating?
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Relay not secure in socket or
relay faulty - replace
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