CBFF - Boiler Shutting Down/Lockout

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Combi boiler shutting down irregularly.
- Vent cap closed.
- Seized float/needle valve due to rust/sludge/scale.
Boiler Cycling
- Sludge/scale build up in main heat exchanger.
- Boiler thermostat failed.
- No means of providing boiler interlock.
Combi Boiler Shuts Down/Lockout before Demand is Satisfied.
- Additional radiators fitted with thermostatic radiator valves.
- additional thermostatic valves added.
- last/highest radiator not reaching temperature.
- fan is faulty/failing.
- no automatic by-pass valve fitted.
- Room/programmable room thermostat set too low or incorrectly sited.
- Solenoid is faulty when hot.
- Reverse polarity. L&N connections wrong way around.
Boiler lockout
- Condensate formed ice plug in pipe work.
- Condensate not running away.
Combi boiler fires ok, when demand stops, goes. To lockout.

Pump or fan over-run has failed, overheat thermostat operated, combi goes to lockout.
Combi Boiler Shut Down (Overheat)
- Expansion vessel faulty.
- Air trapped in system.
- Water leak.
- By-pass valve faulty.
- Air pressure switch faulty.
- Pump failing/failed.
- Pump fitted the wrong way around.
- Sludge/scale built up in heat exchanger and kettling.
- Thermistor loosing calibration/failed.
- Overheat thermostat faulty.
- high limit thermostat faulty.
- thermostat phial incorrectly positioned.
- Gas rate too high.
- Faulty gas valve.
- Solenoid sticking in on position.
- Gas regulator at gas meter faulty.
- undersize gas supply pipe work.
- FSD incorrectly positioned/faulty.

Author

zenken79

313717

Card Set

CBFF - Boiler Shutting Down/Lockout

Description

Combi boiler fault finding - Boiler Shutting Down/Lockout

Updated

2016-01-04T12:39:43Z

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