Thermo Products MDA1-75N, MDA1-50N, MHA1-75N, MHA1-100N, MHA1-50N, MHA1-125N, MDA1-125N, MDA1-100N

Contents Induced Draft Highboy COUNTERFLOW/HORIZONTAL GAS Furnace Section Safety II. Installation Guidelines Page Shipping Damage PackagingSafety Codes II. Installation GuidelinesCloset and Alcove Installation Installation LocationRefer to Figure Standard ClearancesNon-combustible Material Plenum Flue or Vent All Models Covered by This ManualAir for Combustion and Ventilation MDA1 Horizontal Installation MDA1 Installed Horizontal Duct Work and Air Conditioning Filters/ Filter InstallationOptional Thermo Pride Filter Rack Use of Non-Thermo Pride Filter Retention MeansFormula FPMVenting Carbon Monoxide Poisoning Hazard Replacing An Existing Furnace From a Common VentCondensing in the Chimney Page Page Vent Connection to Inducer Inducer Mounting Automated Literature FAX Sidewall VentingHorizontal Size and Length for Sidewall Venting Horizontal Size and Lengths for Horizontal VentsGeneral GAS Piping Fire or Explosion Hazard GAS PipingPage Typical Gas Piping Installation of Natural GAS PipingSteel Pipe Size for Natural Gas IPS Installation of Propane GAS PipingPage Electrical Field Wiring and Replacing WiringRoom Thermostat Electronic Air Cleaner and Humidifier ConnectionsBlower and Control Panel Initial Startup To delay fan Set SwitchWhat to do if YOU Smell GAS To Turn Off Gas To Appliance Adjustment Of Heat Input Rate Page Burner Adjustment Typical Observation of Main Burner Flames Setting Supply Air Temperature RiseImportant Remove flue blockage when done Checkout ProcedureLED will also flash once at power-up Diagnostic FeaturesGeneral Inspection Shut off gas and disconnect power before continuingHouse Air Blower Filter Replacement Filter Maintenance ProcedureReturn Air Filter VI. Installers Instructions to User Appendix a Sources for Reference Standards Sequence of Operations for Heating System Appendix B Sequence of OperationsMode of Operation Control System Action Heating System Appendix C Troubleshooting FlowchartsYes Is ignitor positioned Correctly? Does system run until thermostat is satisfied? Description Part Number QTY MDA1/MHA1-50S00S4426Appendix E Replacement Parts List MHA1 Page Replacement Parts List MDA1 Page Appendix F Wiring Diagram Page MID-EFFICIENCY Highboy GAS Furnace SPECIFICATIONS5 Appendix G MID-EFFICENCY Furnace SpecificationsNominal temp. rise Heating fan speed