Nordyne M3RL Series installation instructions Conversion, Leak Check, High Altitude Derate

Main
Blower
Control
Board
Inducer
Burner
Box
Gas
Valve
Floor
	Alt. Gas
To Gas	Line Entry
Supply

Figure 22. Typical Gas Piping

If the test pressure is less than or equal to 1/2 psig (14 in. water column), the furnace must be isolated from the gas supply line by closing the manual shut-off valve.

Leak Check

After the gas piping to the furnace is complete, all connections must be tested for gas leaks. To check for leaks use only a soap and water solu- tion or other approved method.

High Altitude Derate

The nameplate input rating for the furnaces apply for elevations up to 4,000 feet above sea level for US and Canada. If the elevation for the furnace location is higher than 4,000 feet above sea level, the furnace input must be derated by using the appropriate orifice size listed in Table 8.

NOTE: The density of air decreases with in- creasing elevation above sea level. This re- duces the quantity of combustion air drawn into the furnace under normal operation and requires the unit be derated by using smaller gas orifices or lower manifold pressure.

CONVERSION

This furnace can be converted from the fac- tory-equipped gas to either natural gas (for LP gas ready models), or LP gas (for natural gas ready models). Conversions must be made by qualified service personnel, using only factory authorized or approved parts. The required conversion orifices are supplied with the fur- nace.

!WARNING:

DO NOT REMOVE OR DEFACE THE ORIGINAL RATING PLATE.

!CAUTION:

The gas supply shall be shut off prior to disconnecting the electrical power, before proceeding with the conversion.

To Turn Off Fuel Supply to the Appliance:

1.Set the room thermostat to “OFF” or its lowest temperature setting.

2.Turn OFF the main gas supply to the appli- ance at the manual valve, outside of the appliance casing.

3.Remove the control access panel / lou- vered door.

4.Move the appliance gas valve lever/knob to the “OFF” position.

5.Turn OFF the electrical power to the appli- ance.

CAPACITY OF BLACK IRON GAS PIPE (CU. FT. PER HOUR)

FOR NATURAL GAS (SPECIFIC GRAVITY - 0.60)

NOMINAL				LENGTH OF PIPE RUN
BLACK IRON						(feet)
PIPE DIAMETER
(in.)		10	20	30	40		50	60	70	80
1/2		130	90	75	65		55	50	45	40
3/4		280	190	150	130		115	105	95	90
	1	520	350	285	245		215	195	180	170
1	1/4	1050	730	590	500		440	400	370	350
1	1/2	1600	1100	890	760		670	610	560	530

The cubic feet per hour listed in the table above must be greater than the cubic feet per hour of gas flow required by the furnace.

To determine the cubic feet per hour of gas flow required by the furnace, divide the input rate of the furnace by the heating value of the gas:

Cubic Feet	=	Input To Furnace (Btu/hr)
Per Hour Required		Heating Value of Gas (Btu/Cu. Ft.)

Table 7. Capacity of Black Iron Gas Pipe (cu. ft. per hour) for Natural Gas (specific gravity = .60)

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