Section V Electrical Power | Johnson Controls CP8C/CPLC*MP instruction

368262-UIM-B-1008

GAS CONVERSION FOR PROPANE (LP)

This furnace is constructed at the factory for natural gas-fired operation, but may be converted to operate on propane (LP) gas by using a fac- tory-supplied LP conversion kit which includes a LP gas valve. Follow the instructions supplied with the LP kit.

LoNOx furnaces requiring propane (LP) gas must have the LoNOx screens removed prior to installation and operation. See propane instructions.

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
Actual Rate	4,000	5,000	6,000	7,000	8,000	9,000	10,000
(percent of	4,000	5,000	6,000	7,000	8,000	9,000	10,000
(percent of	84%	80%	76%	72%	68%	64%	60%
nameplate)	84%	80%	76%	72%	68%	64%	60%
			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.