Nordyne M1G Service Manual
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Nordyne M1G Service Manual

M1 series
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M1 Series
M1G and M1M Furnaces
Service Manual

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Summary of Contents for Nordyne M1G

  • Page 1 M1 Series M1G and M1M Furnaces Service Manual...
  • Page 2 Typical meters used to service M1 furnaces. A. Differential Pressure Gauge B. Volt-Ohm Meter C. Manometer D. Inclined Manometer...

  • Page 3: Table Of Contents

    Line voltage ............. 8 Pilot Outage Chart ..........23 Low voltage ............. 9 WIRING DIAGRAMS M1G, Natural Draft, AC adaptable ......24 5. GAS SUPPLY,CONVERSION AND LIGHTING M1G, Natural Draft, AC ready ......24 M1G,M1M MODELS Gas piping ............. 10 M1G, Forced Draft, AC adaptable ......

  • Page 4: Introduction

    INTRODUCTION It will be necessary for you to accurately identify the unit you This service manual is designed to be used in conjunction with the installation manual provided with each furnace. are servicing, so you may be certain of approved diagnosis and repair.

  • Page 5: Clearances And Hud Requirements

    NOTICE TO INSTALLER “A” cabinet models may be installed with Optional Coil Cabi- net Model #911969 for air conditioning. Installer is advised to follow carefully all instructions and warnings in this manual to insure maximum performance, “B” cabinet models are factory equipped with a built-in coil cavity. safety, and operating efficiency of these appliances.

  • Page 6: Circulating Air Supply

    a. Federal Manufactured Home Constructions & Safety a. Regardless of the location, the return air opening into the Standard (H.U.D. Title 24, Part 3280.707[a][2]) closet shall not be less than specified in the appliance’s b. American National Standard (ANSI-119.2/NFPA-501C) listing. for all recreational vehicle installations.

  • Page 7: Supply Air Systems

    Use jack assembly. On the M1G furnace (natural draft model) the NORDYNE’s certiduct program to determine proper air inlet limit tripping is caused from a unbalanced draft, which duct size for A/C.

  • Page 8: Application Of High Wind And Arctic Caps

    ELECTRICAL WIRING Is gas orifice the proper size for the gas in use? Check manifold gas pressure at low fire (14 seconds Line Voltage Wiring (See Figure 15) nominal) before it steps to normal high fire. The line voltage (115 volt) to the furnace must be supplied The compression fitting on the pilot tube must be tight.

  • Page 9: Low Voltage

    M1G A/C Supply Voltage Thermostat Ready Furnace Supply voltage to the furnace should be nominal 115 volts. It must be between 103 volts and 127 volts. Supply voltage to the furnace should be checked with furnace in operation and blower running.

  • Page 10: Gas Supply,Conversion And Lighting M1G,M1M Models

    5. GAS SUPPLY, CONVERSION, AND LIGHTING – M1G AND M1M MODELS GAS PIPING Sizing and installation of fuel lines must be in accordance with federal, state and local regulations. All piping shall be black iron pipe, or equivalently sized steel tubing. Internally tinned On-Off-Fan copper tubing may be used for gas supply systems.

  • Page 11: Gas Safety Nat And Lp

    ORIFICE SIZE - LP OUTPUT- MBTUH 61.7 56.9 54.6 52.4 50.3 48.3 46.4 44.5 42.7 41.0 ORIFICE SIZE - NAT. GAS M1G 077 ORIFICE SIZE - LP OUTPUT- MBTUH 59.9 55.2 53.0 50.9 48.9 46.9 45.0 43.2 41.5 39.8 ORIFICE SIZE - NAT. GAS...

  • Page 12: Proper Pilot Lighting M1G Only

    LIGHTING INSTRUCTIONS FOR STANDING TO TURN OFF GAS TO APPLIANCE: a. Set the thermostat to the lowest setting. PILOT MODELS b. Turn off all electric power to the appliance at breaker or fuse box, before servicing. a. Stop! Read the safety information. c.

  • Page 13: Accessories

    Relay Boxes cold air from being discharged up around the heat exchanger. Only the M1GH requires a relay box. All other M1G and M1M Cold air may cause condensation inside the heat exchanger, furnaces are AC ready. The M1GH series furnaces are which can lead to rust and early failure.

  • Page 14: Standing Pilot Model M1G

    Standing Pilot Model M1G Furnace Sequence of Operation Troubleshooting Wiring Diagrams...

  • Page 15: Troubleshooting Flow Chart M1G-056-070

    Troubleshooting Sequence – M1G 056-070 Power up Selector Switch Power On Call for heat, Check voltage L1 A/C Voltage t-stat closes R-W at WxC Check incoming Power at gas Check circuit from secondary power supply to valve furnace and voltage through all safety switches...

  • Page 16: Troubleshooting Flow Chart M1G-077-090

    Troubleshooting Sequence – M1G 077-090 Combustion Blower Model Power up Selector Switch Power On Call for heat, Check voltage Refer to Low Voltage and L1 A/C Voltage t-stat closes R-W at 1 and 3 on Limit Control sections Combustion Relay...

  • Page 17: Sequence Of Operation Heating

    Transformer (Picture 3) 7. Standing Pilot Model M1G All M1G furnaces are protected by a fuse in the 24 vac circuit. The transformer supplies control voltage (24 vac) by stepping SEQUENCE OF OPERATION FOR STANDING PILOT down the supply (primary) voltage from 115 vac to 24 vac On a call for heat, the thermostat contacts close, supply- (secondary voltage).

  • Page 18: Low Voltage Wiring

    Combustion Air Relay – The combustion air relay is used Silicone only on the M1G 077-090. On a call for heat, the relay activates the combustion air motor. The relay is energized through the thermostat from the “W” terminal. It has a 24VAC coil powered by the “W”...

  • Page 19: Burner Assembly

    Under normal operating conditions, once the ventor motor 3. If motor is not running, no negative will be created and builds up to speed sufficient differential (negative) pressure assembly will have to be replaced. (See combustion air (approximately -0.30” wc) will be created to close the differen- assembly replacement) tial pressure switch and keep it closed the whole heating cycle.

  • Page 20: Gas Valve

    Remove furnace door and set the gas valve in the OFF turned off. The valve is a “step-open” type for M1G*-models position. – which means it opens to a “low-fire” position, and after 14 b.

  • Page 21: Fan Switch

    To change thermocouple: If blower motor does not shut off and chamber has cooled (and 1. Follow the same steps used to remove pilot assembly fan switch is off), check across fan switch contacts. If there is 2. Remove pilot tube close-off plate by removing the phillips no voltage, pull the single orange wire off (take care not to screw on the burner plate.

  • Page 22: Heat Exchanger

    If this occurs inspect the heat exchanger. Roll Out Switch - (M1G* - 056 & 070) The furnace is protected by a manual reset safety switch located on the Note: The furnace does not have to removed from its alcove bottom left hand side of the combustion pipe.

  • Page 23: Pilot Outage Chart

    Pilot Outage Chart Mechanical (Internal to Furnace) Problem Possible causes Solutions 1. No pilot Flame No inlet gas pressure. Check sources. Plugged pilot orifices. Clean or replace orifices. Pilot lights with button held, but Pilot not contacting 3/8” to 1/2” top of Clean and or adjust pilot.

  • Page 24: Wiring Diagrams M1G, Natural Draft, Ac Adaptable

    NOTE: To run at same speed in both heating and cooling mode, remove wire from either terminal 4 or 6 on the relay, then attach GAS VALVE jumper to terminals 4 and 6. 7038890 Figure 19. Gas Atmospheric Furnace, A/C Ready, M1G (B, C, D) 056, 070 Models...

  • Page 25: M1G, Forced Draft, Ac Adaptable

    FURNACE ELECTRICAL BOX * Jumper Wire - M1GB Units Only LEGENDS Otherwise Hi-Speed Connected 115V: FIELD 115V: to Blower Relay 24V: FIELD 24V: VALVE Figure 21. Standing Pilot with Induced Draft Furnace, A/C Ready M1G (B, C, D) 077, 090 Models...
  • Page 26 Hot Surface Ignition System Model M1M Furnace Sequence of Operation Troubleshooting Wiring Diagrams...

  • Page 27: Hot Surface Ignition System Model M1M Troubleshooting Flow Chart

    Troubleshooting Sequence – M1M Call for heat, Check for voltage Inducer starts Circuit board 3 blinks t-stat closes R-W at inducer molex plug Replace Pressure switch Replace Inducer Check for red light Check fuse on 24 Volt, C to W Board stuck closed Blower...

  • Page 28: Sequence Of Operation Heating

    Steady heat: Control inputs are continuously monitored to 8. Hot Surface Ignition System ensure limit and pressure switches are closed, flame is Model M1M established, and the thermostat call for heat remains. Post purge: When the thermostat demand for heat is satisfied, SEQUENCE OF OPERATION M1M SERIES the control de-energizes the gas valves.

  • Page 29: Low Voltage Wiring

    Transformers open on primary indicate low voltage short circuit. Transformers open on secondary indicate an overload (a current draw that exceeded rating). Low Voltage Wiring Stand off Install the thermostat per the manufacturer's instructions. The Holes low voltage (24 vac) connections from the thermostat are made at the pigtail wires coming off the control board in the furnace.
  • Page 30 1. Power Line Polarity – The “hot” side of the power line open momentarily within 2 seconds prior to the flame loss. must be connected to the “L1” for the control to be able to If the pressure switch was open any time within the 2 sense flame.

  • Page 31: Combustion Air Blower

    Power interruption greater than 80mS may cause the control to interrupt the operating sequence and resume Orifice as if power was first applied. All power interruptions of any Ring duration are to be self recovered and not result in a condition that could cause lockout.

  • Page 32: Pressure Switch

    Under normal operating conditions, once the ventor motor Combustion motor assembly replacement builds up to speed sufficient differential (negative) pressure Using the information from above you have determined the (approximately -0.30” wc) will be created to close the differen- combustion motor assembly needs to be replaced, follow the tial pressure switch and keep it closed the whole heating outlined procedures.

  • Page 33: Hot Surface Ignitor

    2. If there is a heat exchanger restriction or exhaust restriction 7. The ignitor may also be ohmed out. The ignitors usually range from 125 to 150 ohms at 70°F/21°C. (any restriction after motor), it will cause a lack of negative pressure.

  • Page 34: Blower Assembly

    of full flow, but is also not field adjustable. At the end of the dwell 6. Remove motor and replace. NOTE: Some motors are time, the main valve opens, allowing full gas flow. torsion-flex mount and some are band around mount. See picture below.

  • Page 35: Wiring Diagram

    WIRING DIAGRAM Figure 25. Gas Direct Ignition Furnace, Heating & A/C Ready - All M1M Models...
  • Page 36 UTEC M1 FURNACE CONTROL SEQUENCE Start-Up / Shut-Down Thermostat Off (Break R to W) Thermostat on call for heat (R to W) Main Blower Main Blower Flame Proving Gas Valve Gas Valve Factory Set Igniter at 120 seconds Inducer Inducer Elapsed Time Line - Seconds Elapsed Time Line - Seconds NORMAL START-UP SEQUENCE...

This manual is also suitable for:

M1m

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