Kärcher HDS4.0/22 Dealer's Manual

Also see for HDS 3.9/30: Operator's manual Operator's manual

Contents

28MaintenancePropane GasGeneral Safety PrecautionsHave a qualified gas service person assist in any gasburner installation or service. Few maintenance peopleor mechanics are knowledgeable in gas controls orrelated safety practices. Propane gas is heavier thanair; unburned propane gas will gravitate to the floorrather than rise out of the stack. Hence, adequate floorspace and good ventilation are especially importantwith propane systems.Gas Pressure RequirementsAll propane fired machines operate on vapor propanefuel only. They are designed to operate at a pressure of11 w.c.i.... (between 1/3 and 1/2 of one psi), and areoften operated at even higher pressures when extraheat is needed.Exterior regulators are needed to control gas pressure.Propane bottles are not included with the machine. Apressure regulator should be installed betweenpropane bottle and gas valve.Propane Cylinder CapacityAn important consideration with propane systems is thecapacity of the supply cylinder relative to the needs ofthe burner. The burner operates on propane as a vaporgas. As gas is used from the propane cylinder, theliquid in the cylinder boils to maintain vapor gaspressure. This boiling process cools the liquid, and in aheavy, continuous-demand situation, the liquidtemperature can fall to the point at which it cannotprovide vapor gas as rapidly as is needed. In this case,it may be necessary to warm the propane cylinder bydirecting a warm spray, not over 120°F, on the coldcylinder or by manifolding two propane bottles togetherto increase total vaporization capacity. It is recom-mended that a minimum 100 lb. vapor propane bottlebe used on the machine, depending on the length ofrunning time desired.Burner FeaturesOperated Automatic ValveThis machine is equipped with an Intermittent PilotIgnition System. This system is designed to eliminatethe need for a constant burning pilot. Lighting of thepilot is accomplished through electronic spark ignitioneach time the burner switch is turned on. Do notattempt to light the appliance manually as a burn injuryor electrical shock may result. The pilot light will remainon and the main gas valve is turned off when the spraygun is closed.Care of Main BurnerDue to condensation from heater coils dripping downon the burners, scale build-up may occur in the burnerjet orifices.1. TO REMOVE BURNER MANIFOLD FROMWATER HEATER COIL:Turn off the gas to the main burner by turning theknob to the “OFF” position on the gas valve and themain gas supply.Disconnect the pilot and ignition lines from the gasvalve. Disconnect union in main burner line belowthermostat. Slide burner manifold out through shellopening.2. TO CLEAN BURNER JETS:Select proper size drill for type gas involved. Usepin vise to hold drill and ream out each jet orifice.CAUTION: Do not ream out orifices to alarger size.If the water heater will be exposed to freezing weather,an anti-freeze solution should be circulated through thecoil by whatever means are available for the particularsystem the water heater is used on.To Adjust Pressure RegulatorAdjustment of the pressure regulator is not normallynecessary since it is preset at the factory. However,field adjustment may be accomplished as follows:1. Manometer attachment may be accomplished atthe pressure tap plug.2. Remove regulator adjustment screw cap.3. With small screwdriver, rotate adjustment screwclockwise to increase, or counterclockwise todecrease pressure.Replace regulator adjustment screw cap.Karcher Liberty HDS Stationary Dealer’s Manual 9.801-508.0 - AY