Boiler Manual - Weil-McLain

GV90+ gas-fired water boiler — Boiler ManualTroubleshooting (continued)Figure 94 Common causes and possible corrections, part 1Symptom Common Causes Possible CorrectionsRapid cycling — boilerturns on and off frequentlyThermostat installed where draftsor heat affect readingLocate thermostat on inner wall away fromheat sources or cool drafts.Heat anticipator in thermostatadjusted incorrectlyAdjust thermostat per manufacturer’sinstructions.Incorrect limit settingSet limit according to system needs.Maximum setting is 200°F. Increase limitsetting to decrease cycling.Insufficient water flow throughboilerCheck all valves to and from boiler. Returnto proper setting.Confirm circulator size.Frequent release of waterthrough relief valveExpansion tank sized too smallCall qualified service technician to checkexpansion tank operation and size.Flooded expansion tankCall qualified service technician to checkexpansion tank operation.Inoperative limit controlCall qualified service technician to replacelimit control.Need to frequently addmakeup waterLeaks in boiler or pipingHave qualified service technician repairleaks at once to avoid constant use ofmakeup water. Makeup water can causemineral deposits which, in turn, can causeboiler section failure. Do not use petroleumbasestop-leak compounds.Black water conditionOxygen corrosion due to leaks inboiler and pipingHave qualified service technician repair atonce. Keep pH of water between 7.0 to 8.5.Part number 550-142-054/1211 79