https://jme-training-academy.com/index.php?action=history&feed=atom&title=Heating_System_No_Heat_Fault_GuideHeating System No Heat Fault Guide - Revision history2026-06-17T10:39:45ZRevision history for this page on the wikiMediaWiki 1.45.3https://jme-training-academy.com/index.php?title=Heating_System_No_Heat_Fault_Guide&diff=33&oldid=prevMorgan Allen: Created page with "= Heating System No Heat Fault Guide = == Purpose == To systematically identify why a heating system is not calling for heat or not firing the boiler. --- == 1. Initial Checks == * Confirm system has power (boiler, programmer, controls) * Check programmer is set to ON or timed correctly * Check thermostat setpoint is above room temperature * Check for any obvious error codes on boiler --- == 2. Confirm Demand Signal == * Increase thermostat temperature * Listen/obse..."2026-06-10T14:37:37Z<p>Created page with "= Heating System No Heat Fault Guide = == Purpose == To systematically identify why a heating system is not calling for heat or not firing the boiler. --- == 1. Initial Checks == * Confirm system has power (boiler, programmer, controls) * Check programmer is set to ON or timed correctly * Check thermostat setpoint is above room temperature * Check for any obvious error codes on boiler --- == 2. Confirm Demand Signal == * Increase thermostat temperature * Listen/obse..."</p>
<p><b>New page</b></p><div>= Heating System No Heat Fault Guide =<br />
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== Purpose ==<br />
To systematically identify why a heating system is not calling for heat or not firing the boiler.<br />
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---<br />
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== 1. Initial Checks ==<br />
* Confirm system has power (boiler, programmer, controls)<br />
* Check programmer is set to ON or timed correctly<br />
* Check thermostat setpoint is above room temperature<br />
* Check for any obvious error codes on boiler<br />
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---<br />
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== 2. Confirm Demand Signal ==<br />
* Increase thermostat temperature<br />
* Listen/observe for system response:<br />
* Valve movement (if present)<br />
* Relay clicks in wiring centre<br />
* Boiler ignition attempt<br />
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---<br />
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== 3. Check Controls ==<br />
* Room thermostat operation<br />
* Programmer output (heating channel ON)<br />
* Smart thermostat receiver status (if fitted)<br />
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---<br />
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== 4. Check Zone Equipment ==<br />
* 2-port valve opening (S-Plan)<br />
* 3-port valve movement (Y-Plan)<br />
* End switch operation sending boiler signal<br />
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---<br />
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== 5. Boiler Demand Check ==<br />
* Confirm switched live reaching boiler control terminal<br />
* Check boiler enable input is present<br />
* Verify no internal boiler lockout<br />
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== 6. Electrical Fault Isolation ==<br />
* Check for loose neutrals in wiring centre<br />
* Check for broken switched live circuits<br />
* Check for failed relay outputs in controllers<br />
* Check fused spur supply integrity<br />
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== 7. Common Real-World Causes ==<br />
* Failed motorised valve actuator<br />
* Stuck valve not opening fully<br />
* Thermostat not calling correctly<br />
* Broken switched live wire<br />
* Wiring centre terminal loose connection<br />
* Smart thermostat receiver failure<br />
* Boiler interlock missing or bypassed<br />
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== 8. Conclusion ==<br />
Most no-heat faults are caused by control signal failure, not boiler faults. Always trace demand from thermostat → valve/controller → boiler.</div>Morgan Allen