L.B. White 140 Owner's Manual And Instructions

Contents

L.B. White 140 Owner's Manual And Instructions Manual pdf 17 page image

PRESSUREVALVEAPPLY LOCTITEBYPASS GASSUPPLY TUBEPILOT BUTTONCOMPRESSIONNUTPRESSURE VALVECOMPRESSION NUTINJECTOR BODYPILOT CONTROL VALVEA. Removal1. Loosen gas supply tube compression nuts andremove gas tube. See Fig. 18.2. Remove pressure valve from injector body by firmlygrasping the pressure switch and turning it counterclockwise.ATTENTION■ The replacement pressure valve will ship with a smalltube of Loctite thread lock.■ Apply Loctite sparingly (normally 2 drops is sufficient)to the upper threads of the adapter. See Fig. 19.■ Thread the pressure valve into the injector body. Thebottom of the valve should contact the injector body,and the gas inlet of the valve is perpendicular to theinjector body.FIG. 18FIG. 19B. AdjustmentThe pressure valve is responsible for delivering gas to thesecondary orifice and in turn to the combustion cones.Under normal operation, heaters within a specific zone willmodulate the heat output through a gas pressure range of10 in. W.C. to 5 psig. To accomplish this full range of heatmodulation, gas pressure is constantly supplied to theprimary burner orifice and to the secondary orifice via thepressure valve. The pressure valve is factory-set to open at50-54 in. W.C. (approx. 2 psig) pressure. When thethermostatic head opens on a call for heat gas pressurebetween 2 and 5 psig gas is delivered to the combustioncones through both the primary and secondary orifices forfull heat output.Although rarely needed, the pressure valve may requireadjustment after significant operation time if it is observedthe pressure valve of a heater opens at a slower or fasterrate than other heaters within a zone. The opening point ofthe pressure valve is indicated by observing the innercombustion cone flame color and size. As the pressurevalve opens, the flame at the inner cone changes from alight blue flame to a larger red/orange flame. Thisprocedure may require the assistance of another person.INITIAL PPREPARATION-- Close fuel supply to zone panel.-- Clean heater thoroughly.-- Connect an accurate 0-100 in. W.C. pressure gaugeto zone panel.-- Remove spring from zone panel regulator. Replaceit with spring that allows pressure adjustmentrange to 65 in. W.C. (Available from L.B. White,Part # 21876)-- Open fuel supply to zone panel and light heaters.-- Adjust thermostatic head back to minimum setting.PROCEDUREIt is suggested to perform this procedure in a low lightcondition. Slowly increase gas pressure at zone panelregulator to 52 in. W.C., observing the opening point of thepressure valve. If the pressure valve opens at any pressureother than 52 in. W.C., perform the following:-- Remove pressure valve cap.-- Turn the valve’s adjusting screw all the way in(clockwise).-- Set zone panel pressure to 52 in. W.C.-- Slowly turn the pressure valve screw out(counterclockwise) until the pressure valve opens.COMPLETION-- Replace pressure valve cap.-- Adjust thermostat on zone panel to highest setting.-- Remove test spring from regulator on zone paneland replace with original spring.-- Adjust thermostatic head to minimum temperature.-- Set zone panel regulator to 10-12 in. W.C.-- Set thermostatic head to desired temperature.17MAIN BURNER PRESSURE VALVEGAS SUPPLYTUBE