Thermo Pride GMC-85, Installation And Service Manual

All installations and services must be performed by qualified service personnel.

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H.  FUEL PIPING 
 

Sizing and installation of fuel lines must be in accordance with federal, state and local 
regulations. 
 
1.  General Gas Piping (GMC-85) 

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Because of the potential of the odorant to fade, a gas leak may not be detected by 

smell. If this furnace is installed below grade, contact your gas supplier for a gas detector.

 
A qualified installer or service person must install all gas piping and perform all required testing. 
Piping from the natural gas meter to the furnace shall be in accordance with requirements of the 
local gas utility. Piping from the propane tank to the furnace must follow the recommendations 
of the gas supplier. In the absence of local codes governing gas piping selection and installation, 
follow the National Fuel Gas Code, ANSI Z223.1 / NFPA 54-1999, or latest edition. 
 
A readily accessible, manual gas shutoff valve (design-certified for the applicable gas) with a 
non-displaceable rotor member shall be installed within six feet of the furnace. 
 
A pipe union, or flanged connection, shall be provided directly up stream of the burner to allow 
burner removal. Unions must be of a ground joint type or flange-jointed type using a gasket 
resistant to the corrosive effects of LP gases. Pipe dope or sealant design-certified to be resistant 
to the action of the LP gases should be used on all threaded joints. 
 
The burner is setup to be piped to the gas supply through the left-hand side of the furnace. For 
service purposes, it is recommended the gas union be located inside the furnace. 
 
A drip leg must be used on both propane and natural gas installations immediately upstream of 
the furnace in order to trap oil, condensate, and other impurities which might otherwise lodge in 
the gas valve, or plug the main burner orifice. A drip leg shall be provided at the outlet of the gas 
meter when there is excessive condensation between the gas meter and the furnace.  
 
Failure to install drip leg(s) may void the manufacturer’s limited warranty on the furnace. 

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With the gas piping pressurized, all gas piping connections must be leak tested 

using a strong soap and water solution. Any leaks must be repaired immediately after turning 
off the gas supply. A final test for gas leakage must be made after purging the gas line. 
 

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DO NOT wet electronic components during the leak test. Wetting electronic 

components may damage circuitry and cause a hazardous situation. Dry moisture from all 
leads and terminals if wetting occurs. Wait at least 24 hours for the circuit to fully dry before 
energizing the system.