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Tim H.
Tim H., HVAC Professional
Category: HVAC
Satisfied Customers: 3971
Experience:  Experienced in all aspects of HVAC, both residential and commercial.
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have a weather king gas furnace with intermittent delayed ignition.get

Customer Question

have a weather king gas furnace with intermittent delayed ignition.get big boom.has a rnd ceramic ignitor.when it clicks and lights the pilot the burners light right away and no boom.when the pliot doesnt light right away the clicking continues and you hear the gas and then get the big boom .pulled the burners out checked crossover tube ok.had gas valve replaced. about 9 years ago.I thought the gas valve was not to open if the flame sensor has no pilot flame hitting it.model GUWHL-100ADS.Thanks T.P. l
Submitted: 6 years ago.
Category: HVAC
Expert:  Tim H. replied 6 years ago.
Thanks for giving me the opportunity to help! You are correct. If the burners are not lit and making the flame sensor, the gas should shut off. Have you checked all the burners to make sure they are clean and free of rust and not warped? Are they igniting smoothly across all burners or are 2 or 3 lighting and not the rest? Is your ignitor weak? These are some of the things I'd check.
Tim H. and 2 other HVAC Specialists are ready to help you
Customer: replied 6 years ago.
burners and crossover good shape.should main gas valve open if the pilot has not lit yet due to weak ignitor
Expert:  Tim H. replied 6 years ago.
Hot surface ignition goes like this: inducer motor starts, makes pressure switch. The pressure switch closes and sends power to the ignition module. The ignition module starts the ignition process by warming up the ignitor for a preset period of time and then opening the gas valve. If flame is not established and verified by the flame sensor within so many minutes, the gas valve shuts off.