Rating The Furnace - Goodman GMP Installation & Operating Instructions Manual

Power vented multi-position gas furnace

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Installation & operating instructions manual (18 pages)

Table Of Contents

Table of Contents

The following method should be used in measuring the amp draw of the control circuit to assure

proper adjustment of the thermostat heat anticipator

The furnace is supplied with orifices sized for natural gas at altitudes up to 2,000 feet using a

heating value of approximately 1,000 Btu/hr, and should not normally require change. If for use at

altitudes in excess of 2,000 feet refer to the instructions included in the factory authorized high alti-

tude kit (HA-02). Should this appliance be converted to LP, refer to the instructions included in the

factory authorized LP conversion kit LPM-01 (LPM-03 for GMPE).

It is important to check and adjust the input rate of the furnace to prevent an overfiring situation.

Overfiring can cause premature heat exchanger failure. The input is controlled by the supply pres-

sure, orifice size, manifold pressure and heating (calorific) value of the gas.

The supply pressure must be measured with this and all other gas burning appliances in opera-

tion. The supply pressure must be adjusted to the pressure range stated on the series and rating

plate. Applications for altitudes in excess of 2,000 feet usually require an orifice change. The ori-

fices must be selected using the table below. The furnace derate is 4% for each 1,000 feet above

sea level. This table is based upon a heating value of approximately 1,000 Btu/ft

The input to the furnace must be checked AFTER reorificing.

For altitudes above 7,000 feet refer to appropriate section of the National Fuel Gas Code, ANSI

Z223.1. To calculate the input of the furnace for installations in altitudes over 2,000 feet, use the

following formula:

CORRECTED INPUT = SERIES & RATING PLATE INPUT - (ALTITUDE X .04) X (SERIES &

RATING PLATE INPUT / 1000)

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