Heating, Air Conditioning, Fridge, HVAC/furnace missbehaving


i have a TEMPSTAR gas furnace model #NUGI075DF03. For the last couple of winters it has been working very sporadically. When it receives a signal from thermostat to kick in, the pilot light comes on for may be 5 seconds but burners don't, then pilot goes out. After few cycles the burners eventually come on and house gets heated to desired temp. There are times when burners come on at first attempt but that's very random. The status LED indicates "Retry delay- third failure to light on same call for heat , trial for ignition after 5 mins delay" when that happens. When burners come on , the LED indicates Normal operation. Lst couple of years it has always came on eventually, but there's time in the winter when the temp dips real low since furnace needs 5 minutes waiting period to repeat 3 attempts to light up burners.
Your advice is much appreciated


Briefly looked up your unit shows it's a condensing furnace with a spark ignition , says the pilot flame should engulf  the flame sensor anywhere from 3/8" to 1/2" on the top part of the sensor, your pilot flame may be weak, and not engulfing the sensor enough, your flame sensor may be bad and not sending a signal to open the gas valve consistently. You may want to call for service before the cold weather sets in.

Heating, Air Conditioning, Fridge, HVAC

All Answers

Answers by Expert:

Ask Experts




40+ years diversified experience.An HVAC/Refrigeration Self Employed Contractor since 1986. NATE Certifield. Answer questions pertaining to Residential and Commercial Air Conditioning , Warm Air Heating, Heat Pump systems.Mechanical and Electrical troubleshooting of these systems.Be as detailed as possible when describing problem.Packaged unit or split systems.No appliance questions.


Installation and Troubleshooting, Mechanical and Electrical, in following areas, Refrigeration ( Walk In and Reach In Coolers and Freezers ) Commercial Roof Top and Packaged Heating/Cooling ( Natural Gas,Propane, Electric, and Heat Pumps ) Computer Room Air Conditoning Systems,Commercial Residential Packaged and Split Systems Air Conditoning and Heat Pumps.Warm Air Oil , Natural and Propane Gas Heating systems.

Graduated from Private Technical School in 1975. An HVAC/Refrigeration Contractor . Have Unlimited Heating/Piping and Cooling Contractor License.Limited Sheetmetal Contractors License.NATE Certifield. York Certifield Master Heat Pump Technician 1986. Served 33 years combination Active Duty Air Force , Air Force Reserves and Air National Guard in the HVAC/Refrigeration Shop/Mechanical Shop. Troubleshooting/Installing HVAC/Refrigeration Equiptment Worldwide. Retiring in 2003 as a Senior NCO ,and a Mechanical Superintendent.

©2017 About.com. All rights reserved.