Lennox International Inc MERIT SERIES GAS FURNACE DOWNFLOW AIR DISCHARGE, ML193DF 2286 − 3038m

TABLE 14

Conversion Kit and Pressure Switch Requirements at Varying Altitudes

	Natural to	High Altitude	LP/Propane	High Altitude	High Altitude Pressure
		Natural Burner		LP/Propane
	LP/Propane		to Natural		Switch
		Orifice Kit		Burner Orifice Kit
ML193
					4501 − 7500	7501 −10,000
Unit
	0 − 7500 ft	7501 − 10,000 ft	0 − 7500 ft	7501 − 10,000 ft	ft	ft
	(0 − 2286m)	(2286 − 3038m)	(0 − 2286m)	(2286 − 3038m)	(1373 −	(2286 −
					2286m)	3048m)
−045
−070		73W37	*73W81	*68W68	74W90	74W91
	*69W73
−090
−110

* Conversion requires installation of a gas valve manifold spring which is provided with the gas conversion kit.

Pressure switch is factory set. No adjustment necessary. All models use the factory−installed pressure switch from 0−4500 feet (0−1370 m).

Testing of Non−Direct Vent Applications for Proper Venting and Sufficient Combustion Air

WARNING

CARBON MONOXIDE POISONING HAZARD!

Failure to follow the steps outlined below for each appliance connected to the venting system being placed into operation could result in carbon monox- ide poisoning or death.

The following steps shall be followed for each ap- pliance connected to the venting system being placed into operation, while all other appliances con- nected to the venting system are not in operation.

After the ML193DF gas furnace has been started, the fol- lowing test should be conducted to ensure proper venting and sufficient combustion air has been provided to the ML193DF as well as to other gas-fired appliances which are separately vented.

If a ML193DF furnace replaces a Category I furnace which was commonly vented with another gas appliance, the size of the existing vent pipe for that gas appliance must be checked. Without the heat of the original furnace flue prod- ucts, the existing vent pipe is probably oversized for the single water heater or other appliance. The vent should be checked for proper draw with the remaining appliance.

The test should be conducted while all appliances (both in operation and those not in operation) are connected to the venting system being tested. If the venting system has been installed improperly, or if provisions have not been made for sufficient amounts of combustion air, corrections must be made as outlined in the previous section.

1 − Seal any unused openings in the venting system.

2 − Visually inspect the venting system for proper size and horizontal pitch. Determine there is no blockage or re- striction, leakage, corrosion, or other deficiencies which could cause an unsafe condition.

3 − To the extent that it is practical, close all building doors and windows and all doors between the space in which the appliances connected to the venting system are lo- cated and other spaces of the building.

4 − Close fireplace dampers.

5 − Turn on clothes dryers and any appliances not con- nected to the venting system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer exhaust fan.

6 − Follow the lighting instruction to place the appliance being inspected into operation. Adjust thermostat so appliance will operate continuously.

7 − Use the flame of match or candle to test for spillage of flue gases at the draft hood relief opening after 5 min- utes of main burner operation.

8 − If improper venting is observed during any of the above tests, the venting system must be corrected or sufficient combustion/make-up air must be provided. The venting system should be re-sized to approach the minimum size as determined by using the ap- propriate tables in appendix G in the current standards of the National Fuel Gas Code ANSI−Z223.1/NPFA 54 in the U.S.A., and the appropriate Natural Gas and Propane appliances venting sizing tables in the cur- rent standard of the CSA−B149 Natural Gas and Pro- pane Installation Codes in Canada.

9 − After determining that each appliance remaining connected to the common venting system properly vents when tested as indicated in step 3, return doors, windows, exhaust fans, fireplace dampers and any other gas-burning appliance to their previous condition of use.

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