A.O. Smith BFM - 120, BFM - 100 manual Troubleshooting, Control thermostat 7.5 Control thermostat

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11 Troubleshooting

11.1 Introduction	This chapter deals with the following problems with the appliance:
	•	Gas smell.
	•	Water leakage.
	•	Explosive ignition.
	•	Poor flame profile.
	•	No hot water.
	•	Insufficient hot water.
	When the appliance is in an error condition, the heat demand is (temporarily)
	ignored, and you cannot draw hot water. The frost protection is also out of
	action. The error conditions are divided into three groups:
	• Lock out errors of the burner control
		In this event, the red error light will be lit on the control panel. The burner
		control is in lockout.
		Once the cause has been rectified, the reset button must be pressed to
		restart the appliance.
	•	Cycling of appliance
		In this case, the appliance continuously attempts to start, but there is an
		error that prevents the heating cycle (9.3 "The appliance's heating cycle")
		from completing successfully. Once the cause has been rectified, the
		appliance will restart automatically.
	•	Blocking errors
		You can recognize this condition when the appliance does not start running,
		despite the fact that the water is colder than the temperature set with the
		control thermostat (7.5 "Control thermostat").

These errors disappear automatically once the cause of the error has been removed, after which the appliance resumes operation by itself.

Possible error conditions are explained in the following troubleshooting tables.

Note

Footnotes referred to in the tables can be found on the last page of each table.

Instruction manual BFM

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Contents Page Page Trademarks Read this manual carefullyLiability More informationGis Table of contents Performing maintenance TroubleshootingWarranty certificate Electrical diagramIntroduction About the applianceWhat to do if you smell gas Regulations Maintenance Forms of notation Target groups Symbol Target groupIntroduction Overview of this DocumentChapter Target groups Description Gis Working principle of the appliance General workingPrinciple Appliance Working principle of the appliance Appliances heating cycle Protection for the appliance Pressure switch Water temperature protectionFlame probe Protection DescriptionUnvented installation Safety of the instal- lationVented installation 3 T&P valveGis Air humidity and ambient temperature InstallationAir humidity and ambient temperature PackagingMaximum floor load InstallationWater composition Working clearancesTechnical specifica- tions Plan and elevation of the appliance Dimensions of the applianceDimens Description General and electrical specificationsBFM100 BFM120 Ion UnitDescription Unit Gas dataNatural gas G20 20 mbar LP gas data G30 30 mbar butaneInstallation diagram Installation diagramCold water side Water connections, VentedRecirculation pipe Hot water sideCirculation pipe Water connections, Unvented See C in the installation diagram 3.5 Installation diagramGas connection Circulation pipeAir supply and flue Introduction Installing chimney flue components for BFM 30, 50Subject Description Concentric wall flue terminal BFMConcentric roof flue terminal BFM 30, 50 Installing chimney flue components for BFM 100 C33 concentric roof flue terminal specifications BFM 30, 50Concentric wall flue terminal BFM100 M2000 MDV SCC C13 concentric wall flue terminal specifications BFM 100Concentric roof flue terminal BFM 100 Electrical connection 11 C33 concentric roof flue terminal specifications BFM 100Mains power Fan Alarm Off Connecting the mains powerGas control for BFM 30 through Checking the supply pressure and burner pressureGas control for BFM BFM BFM 30, 50, 80Conversion Conversion to a different gas categoryConversion to a different gas category Orifice replacementPage Conversion to a different gas category Filling Filling Draining Draining Draining unvented installationsDraining vented installations Gis Control panel ON/OFF switchExplanation of icons Control thermostatControl panel Burner control reset buttonError conditions Status of the applianceOperating modes Status of the appliance Starting and running Starting the applianceAppliances heating cycle Starting and running Shutting down Shutting down the appliance for a brief period OFF modeIsolating the appliance from the mains Shutting the appliance down for a long periodShutting down Control thermostat 7.5 Control thermostat TroubleshootingSymptom Cause Solution Remark Gas smell Troubleshooting general errorsWater leakage Explosive ignitionSymptom Cause Solution Remark Insufficient hot water Troubleshooting insufficient hot waterTroubleshooting No hot water Cycle Symptom Cause Solution RemarkPage Introduction Preparation for maintenance Performing maintenancePerforming maintenance Descaling and cleaning the tankWater-side mainte- nance 12.3.1 Checking the anodesIMD-0235 R2 Clean the orifices Clean the burnersGas-side mainte- nance 12.4.1 Checking the flue baffles Finalising mainte- nance13.1 General warranty Warranty certificate13.2 Tank warranty Conditions for Instal- lation and useWarranty certificate Electrical diagram Electrical diagram BFM Electrical DiagramOptional Components Electrical diagram Index Index 0306