Thermostat on, no spark, no pilot gas problem..!

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posted
20 years ago

Fri, Jan 30, 2004 8:59 PM

We have a Rudd gas furnace. The Thermostat will come on and the fan would run. However, there is no spark to light the burner. The igniter is controlled by the Ignition Control Union (ICU) and it's not getting the 24V that it's supposed to get from the transformer\limit control. I've checked the transformer has 120V coming in and limit control has 110V coming in. They both have ohm measuring around 170. Does this indicated that they're in working order? If so, where else can I check to see why the 24V is not coming over to the (ICU).

Thanks

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- Tony Hwang
  
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posted
20 years ago

Fri, Jan 30, 2004 9:56 PM

Hi, Secondary winding of transformer is 24V AC and it'll be rectified by diode bridge to produce DC the control module needs. Tony

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- CBhvac
  
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posted
20 years ago

Fri, Jan 30, 2004 10:46 PM

Do you have 24VAC from the transformer? If not, then you have a problem and probably more than one. ICU??? You mean ICB if its a Rheem/Ruud, but since you gave no information at all that is required to tell you what may, or may not be wrong, then the best place you can check is your Yellow Pages.