SigmaFire Installation Manual, rev. F - Clayton Industries

SECTION IV - FUEL SYSTEM4.1 GENERALClayton’s SigmaFire steam generators are designed to fire on natural gas, propane, or No.2 distillate light fuel oil. On combination natural/propane gas and fuel oil machines, each fueltype requires its designated burner manifold to operate. These burner manifolds must beexchanged, manually, to match the fuel-type desired. Characteristics of, and installation guidelinesfor, both gas and oil fuel systems are described in detail in the following paragraphs.The SigmaFire models SF-25 and SF-35 steam generators/fluid heaters are step-firedcombustion machines only. The SigmaFire models SF-50 through SF-200 steam generators/fluidheaters are step-fired as standard, but ordered as modulating on gas combustion and step-fired onoil combustion.NOTEThe installing contractors are responsible for ensuring that all pipingand fittings are rated for the intended system installation (materialtype, thickness, pressure, temperature). The installing contractorsare also responsible for ensuring the steam system design meets theflow and pressure requirements of a Clayton steam generator (seeSection VI, Table 1).4.2 NATURAL GASClayton’s SigmFire steam generators are built in accordance with ANSI/ASME CSD-1,(C)UL [(Canada) Underwriters Laboratories], FM (Factory Mutual) guidelines, and IRI (IndustrialRisk Insurers)/GEGAP compliance. High and low gas pressure switches (with manual reset)are standard on all gas trains.Unless otherwise stated (liquid petroleum and other gas operation requires engineeringevaluation), the standard Clayton gas burner is designed for operation using pipeline-quality naturalgas. Gas supply connection sizes and rated gas flows for each model are provided in Tables1and 2 of Section VI. The gas supply line must be sized to provide both the supply pressure andfull rated flow indicated in Table 1 of Section VI without “sagging” (pressure drop). The gas supplypressure must not vary more than +5% of Clayton’s required supply pressure.NOTEAll gas supply piping must include a minimum 12-inch drip leg immediatelybefore Clayton’s gas train connection, and be fully selfsupporting.04/22/2015 4-1 Sect04_FuelSys_SF_f.fm