Service Guide, Burner Adjustments, Combustion AIR

2.Limit Control - This furnace is protected by two high temperature safety limit switches. The auxiliary (upper) limit switch and the high temperature (lower) limit switch are auto- matic reset types. If either limit trips, the burner will shut off. If either limit switch trips off again soon after resetting, set the furnace On-Off switch to the “OFF” position and call your authorized serviceman.

3.Gas Valve - The gas valves for the gas furnaces are a 100% shut-off type and will fail safe if for some reason the gas is turned off. The valve is a “step-open” type for M1G*- models and “slow-open” for M1M*- and M1B*- models which means it opens to a “low-fire” position, and after a few seconds, “steps- open” to “high-fire.”

4.Roll Out Switch - (M1G* - 056 & 070) The furnace is protected by a manual reset safety switch located on the bottom left hand side of the combustion pipe.

5.Oil Burner Primary Control - The primary control for oil gun furnaces starts the burner, monitors a safe operating cycle, and shuts the burner off at the end of a heating cycle. The control uses a light sensing transducer to determine if fuel ignition has been suc- cessfully attained. If ignition is not attained by the end of the safety ignition timing period, the control shuts the burner off and enters “lock- out.”

6.a. Summer Cooling - (H Series): Your fur- nace is equipped to operate the circulating fan only. Turn the Fan On-Auto switch to the “ON” position during warm weather. The blower will now operate to circulate air in your home through the duct system.

b. Summer Cooling - (A, B, C, & D Series): Your furnace is A/C ready, equipped with A/ C relay and transformer. The unit is equipped to use a 4-wire thermostat. When using a 5- wire thermostat, RC and RH should be jumped (see instructions included with ther- mostat).

17. SERVICE GUIDE

BURNER ADJUSTMENTS

Burner settings and adjustments are made at the factory. However, these settings may change during shipping, handling, and installa-

tion. Therefore the following items should be checked and readjusted if necessary.

Atmospheric Gas with Standing Pilot and Direct Ignition Furnaces, Including Gas Gun.

a. Gas Pressure

The gas pressure can be checked with a manometer at the pressure tap located on the side of the gas valve. The gas valve pressure regulator can be adjusted by re- moving the regulator selector stack and turning the slotted insert located directly under the selector stack. The regulator selector stack must be secured in place before each pressure reading is taken. Natural gas manifold pressure should be 3.5" W.C. and L.P. gas manifold pressure should be 10" W.C. Replace the gas pressure tap plug on the gas valve.

b. Pilot Flame (Standing Pilot Only)

The pilot flame can be adjusted by turning the pilot adjustment screw, located on top of the gas valve (See Figure 29). The pilot flame height should be between 3/4” and 1.” The flame tip should be visible just above the pilot bracket when viewed through the observa- tion door. The same pilot orifice is used with both natural and L.P. gas.

COMBUSTION AIR

In order for the flame to burn efficiently, it must receive adequate combustion air. The amount of combustion air required will vary depending on altitude, actual B.T.U. content of the fuel being used, gas pressure, conversion to an- other gas and other factors. The burner flame should be observed and any necessary adjust- ments made before the furnace is placed into service. See Table 9 for Factory Air settings.

Gas Gun

Combustion air box adjustment is made to the main burner by loosening the two lock nuts on the plastic air shutter, located on the left side of the burner blower housing. Air shutter adjust- ment line is located on the same side of the blower housing. Turn the plastic shutter to a smaller number (counter clockwise) for less air to a larger number (clockwise) for more air.

Model	Nat. Gas	LP Gas	Oil
66,000	3.5	3.5	3
86,000	5.3	6	5

Table 9. Factory Combustion Air

Settings

M1M, M1S, M1B, M1G specifications

Nordyne, a renowned player in the HVAC industry, has introduced a range of high-efficiency gas furnaces, including the M1S, M1G, M1B, and M1M models. Each of these furnaces is designed to provide efficient heating solutions tailored to the needs of homeowners.

The M1S series is well-known for its reliability and performance. It features a single-stage heating process that delivers consistent warmth to any space. With its multi-speed blower, the M1S ensures quiet and comfortable airflow, adapting seamlessly to varying temperature demands. Its robust construction coupled with an energy-efficient design makes it an ideal choice for those looking for dependable heating without sky-high utility bills.

The M1G model steps it up with a two-stage heating system that offers enhanced comfort and efficiency. By operating at a lower speed during milder conditions, the M1G can effectively reduce energy consumption while still maintaining a cozy environment. It is equipped with a variable-speed blower that not only enhances efficiency but also minimizes noise, making it perfect for residential areas. The M1G is designed with advanced safety features, including an integrated control board that monitors furnace functions to ensure optimal performance.

For those seeking a budget-friendly option without compromising on quality, the M1B model provides a solid performance with its straightforward, reliable single-stage heating. While it may lack some of the advanced features found in higher-end models, the M1B is built for ease of use with straightforward controls and maintenance, making it a great option for families.

The M1M model integrates cutting-edge technology with a focus on maximum efficiency. Featuring a modulating gas valve, this model can adjust its output based on real-time heating requirements. This adaptability ensures that the furnace operates at peak efficiency, significantly lowering energy bills and improving overall comfort. The M1M also boasts advanced diagnostic capabilities that allow for easy troubleshooting, thus reducing maintenance time and costs.

In summary, Nordyne's M1 series furnaces—M1S, M1G, M1B, and M1M—offer a range of options to meet diverse heating needs. With technologies designed for efficiency, reliability, and comfort, Nordyne continues to solidify its reputation as a leader in the HVAC market, providing homeowners with effective heating solutions tailored to their lifestyles and budgets.