Johnson Controls LM8M/LMLM*MP Section V: Electrical Power, Electrical Power Connections, Input

368261-UIM-A-0508

HIGH ALTITUDE NATURAL GAS ORIFICE CONVERSION

The National Fuel Gas Code requires that gas appliances installed above 2,000 feet elevation have their inputs de-rated by 4% per 1,000 feet above sea level. The modulating furnaces automatically de-rate for altitude by measuring the inducer blower pressure and using that to determine if there is adequate air to support good combustion. If there is not enough combustion air to properly support 100% of the furnace nameplate input rate, the control will reduce the input to the point that there will be good combustion.

The factory gas orifice sizes are based on a gas heating value of 1030 BTU/Cu.ft., so if your gas value is significantly higher or lower than that, it may be necessary to change to smaller or larger gas orifices.

The chart below shows recommended gas orifice sizes to use at vari- ous altitudes and at various de-ration levels. To use the chart, follow these instructions:

1.Clock the gas meter and calculate the actual input rate using your local gas heating value. See "CALCULATING THE FURNACE INPUT (NATURAL GAS)" in this manual.

2.Divide that input rate by the input rate shown on the furnace rating plate to get the actual de-ration percent.

3.Read down the left-hand “Actual Rate” column to find the closest number to your actual de-ration percent.

4.Read across that row to the column for the elevation at your loca- tion. The number listed there is the orifice size that is proper for your unit.

Example – You have a 100,000 BTU/H furnace installed at an elevation of 6,000 feet. You clock the gas meter and find that the furnace is actu- ally fired at 64,000 BTU/H. Divide 64,000 by 100,000, which gives 0.64 (64%). The closest number to 64% in the left-hand “Actual Rate” col- umn is 65. Read across that row to the column for 6,000 feet elevation, which shows “#43”. You should change from the factory #45 orifices to larger #43 orifices, which will bring the input rate back up to approxi- mately 76,000 BTU/H, which is what it should be for that furnace at 6,000 feet.

Table 5: High Altitude Orifices

Actual Rate		Elevation in Feet Above Sea Level
	4,000	5,000	6,000	7,000	8,000	9,000	10,000
(percent of
	84%	80%	76%	72%	68%	64%	60%
nameplate)
			Orifice Drill Size
100	48	49	49	50	51	51	52
95	47	48	49	50	50	50	51
90	46	47	48	49	49	49	50
85	45	46	47	48	49	49	50
80	45	45	46	47	48	48	49
75	44	45	45	45	47	47	49
70	43	44	44	45	45	45	48
65	42	43	43	44	45	45	47
60	41	42	42	43	44	45	46
55	40	41	41	32	43	43	44
50	39	40	40	40	43	42	42

PROPANE KITS

It is very important to choose the correct kit and/or gas orifices for the altitude and the type of gas for which the furnace is being installed.

Only use natural gas in furnaces designed for natural gas. Only use propane (LP) gas for furnaces that have been properly converted to use pro- pane (LP) gas. Do not use this furnace with butane gas.

Incorrect gas orifices or a furnace that has been improperly converted will create an extremely dangerous condition resulting in premature heat exchanger failure, excessive sooting, high levels of carbon monoxide, personal injury, property damage, a fire hazard and/or death.

Propane (LP) conversions are required in order for the appliance to satisfactory meet the application. An authorized distributor or dealer must make all gas conversions.

In Canada, a certified conversion station or other qualified agency, using factory specified and/or approved parts, must perform the conversion. The installer must take every precaution to insure that the furnace has been converted to the proper gas orifice size when the furnace is installed. Do not attempt to drill out any orifices to obtain the proper orifice size. Drilling out a gas orifice will cause misalignment of the burner flames, causing premature heat exchanger burnout, high levels of carbon monoxide, excessive sooting, a fire hazard, personal injury, property damage and/or death.

SECTION V: ELECTRICAL POWER

ELECTRICAL POWER CONNECTIONS

Field wiring to the unit must be grounded. Electric wires that are field installed shall conform to the temperature limitation for 63°F (35°C) rise wire when installed in accordance with instructions. Refer to Table 6, "Ratings & Physical / Electrical Data" in these instructions for specific furnace electrical data.

Table 6: Ratings & Physical / Electrical Data

Use copper conductors only.

Input		Output		Nominal		Total Unit		Air Temp. Rise		Air Temp. Rise		Max	Min. wire Size	Max. Outlet
Max/Min		Max/Min		Airflow			AFUE	Max Input		Min Input		Over-Current	(awg) @ 75 ft	Air Temp
						Amps						Protect	one way
MBH	kW	MBH	kW	CFM	m3/min			°F	°C	°F	°C			°F	°C
60/30	17.6/8.8	48/24	14.1/7.0	1200	34.0	7.0	80.0	35-65	19-36	20-50	11-28	15	14	165	73.9
80/40	23.5/11.8	64/32	18.8/9.4	1200	34.0	7.5	80.0	40-70	22-39	20-50	11-28	15	14	170	76.7
80/40	23.5/11.8	64/32	18.8/9.4	1600	45.3	10.0	80.0	40-70	22-39	20-50	11-28	15	14	170	76.7
100/50	29.3/14.7	80/40	23.4/11.7	1600	45.3	10.0	80.0	40-70	22-39	20-50	11-28	15	14	170	76.7
100/50	29.3/14.7	80/40	23.4/11.7	2000	56.6	17.0	80.0	35-65	19-36	20-50	11-28	20	12	165	73.9
120/60	33.7/16.9	96/48	28.1/14.1	2000	56.6	17.0	80.0	45-75	25-42	25-55	13-31	20	12	175	79.4

Annual Fuel Utilization Efficiency (AFUE) numbers are determined in accordance with DOE Test procedures.

Wire size and over current protection must comply with the National Electrical Code (NFPA-70-latest edition) and all local codes.

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