Camus Hydronics DFH500 Installation, Operation And Service Manual

Also see for DFH1100: Installation, operation and service manual

Contents

Camus Hydronics DFH500 Installation, Operation And Service Manual Manual pdf 17 page image

143.6 CHECKING GAS SUPPLY PRESSURE• Turn the main power switch to “OFF” position.• Shut off gas supply at the manual gas cock in the gaspiping to the appliance. If fuel supply is LP gas, shut offgas supply at the tank.• Remove the 1/8" hex plug from the gas pressure testport located on the inlet gas supply connection at therear of the appliance. Install a fitting in the inletpressure tapping suitable to connect to a manometeror magnahelic gauge. Range of scale should be 0 to14 inch W.C. or greater to check inlet pressure• Turn on gas supply at the field installed manual gascock; turn on LP gas at tank if required.• Turn the power switch to “ON” position.• Adjust the thermostat set point to call for heat.• Observe the gas supply pressure as the burner fires at100% of rated input.• Ensure inlet pressure is within specified range.Minimum and maximum gas supply pressures arespecified in Gas Supply section of this manual.• If gas pressure is out of range, contact the gas utility,gas supplier, qualified installer or service agency todetermine necessary steps to provide proper gaspressure to the control.• If gas supply pressure is within normal range, proceedto remove gas manometer and replace pressure tapfittings in the gas piping to the appliance.• Turn on gas supply at the manual valve; turn on LPgas at tank if required.• Turn the power switch to “ON” position.• Adjust the thermostat temperature set point to thedesired water temperature so the appliance will call forheat.• Check appliance performance by cycling the systemwhile you observe burner response. The burner shouldignite promptly. Flame pattern should be stable, see“Maintenance-Normal Flame Pattern.” Turn system offand allow burner to cool, then cycle burner again toensure proper ignition and flame characteristics.IMPORTANTUpon completion of any testing on the gas system, leak testall gas connections with a soap solution while the mainburner is firing. Immediately repair any leak found in thegas train or related components. DO NOT operate anappliance with a leak in the gas train, valves or related gaspiping.3.7 CHECKING DIFFERENTIAL AIR AND GASPRESSURESFigure 3 – Differential Air Pressure ManometerConnection• The 1 to1 air/gas ratio control actuator has embossedmarkings identifying + air – air, + gas & - gasconnections. Using a test hose assembly fitted withtees, connections can be made from the manometer tothe appropriate ports on the actuator.• Using tees connect a hose from the positive air and thenegative air to each of the two sides of a manometer.This will allow the two pressure points to be measuredwhile at the same time the actuator still receives theproper operating signal.• If a second manometer is available it can be connectedto the appropriate gas ports. Typically the gas signalwill closely follow the air signal on all models. If theincoming gas pressure reduces significantly as theVariable Frequency Drive (VFD) accelerates to 60 Hzthe gas signal may lag behind the air signal by up to15%. This will occur once the actuator has drivendownwards as far as it can go. The amount that theactuator has opened is registered by an indictor armwhich is visible through the view window.• As the appliance comes on and fires, record themaximum inches of water column which is achieved at60 Hz on the VFD using start-up report form (93-0130).To adjust this differential pressure, use the adjustingscrew on the air shutter to the fan. Readings are tocorrespond to the values in table 2a. In all cases thefinal adjustment is to be made using a combustionanalyzer. Depending on field conditions differentialpressures will have to be adjusted accordingly.Typically with long lateral runs the differential signal asread will be reduced from the value shown in the table.The opposite will occur with tall stacks where draftsexceed negative 0.15“W.C.• If the appliance will not light off and the blue ‘mainflame’ light is coming on but not staying on then it willbe necessary to adjust the low fire as explained in thedetailed start-up procedure.