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Question
We have a Lennox G61V 110,000 BTU gas furnace and air conditioning system, installed in 2007. Runs great.  However, whenever the power goes out, whether in heat or AC mode, the furnace won't turn back on when the power returns.  To get the furnace/AC going, I have to go to the breaker panel, turn the power off, then turn it back on.  Sometimes I have to do it a few times before the system turns on.  It has always turned on after doing this, but I am concerned that this is indicative of a larger issue or impending breakdown.  Thanks in advance.

Answer
Lou,

How long has it been doing this ,only recently ? If your t-stat has batteries try replacing them or removing them. You do not need batteries if you have the C terminal ( common ) hooked to your stat and to the furnace C. I personally do not like systems that use battery power minus the common wire not hooked up. If your system does not have a common hooked to the stat and you have an extra wire on the t-stat wire bundle hook it up at the furnace C terminal and C of the t-stat. leave the batteries out. If your handy with a meter ,when this happens again, before you reset the breaker, check to make sure you have 24 volts ac at terminal R to C at the furnace low voltage wire hook up. Needs to be 24-26 volts ac. Not 22 volts. If you have that voltage then get a jumper wire and jump R to G at the furnace , your blower fan should start, if so then jumper R to W for heat, then R to Y for cool , if everything starts , then you have issues with the t-stat. If nothing starts you may haves a defective control board. Did you notice any codes or blinking lights on the board while you were trying to get the unit to restart ?  Sometimes the polarity needs to be changed ( That is one fault ) I find it odd that when you lose power you have to reset the breaker to restart it. What would be the difference if you manually turned off the breaker to the furnace for 15 min. And then turned it back on, would you not get the same problem ?  

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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.

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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.

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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.

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