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Old 02-10-2021, 08:26 PM   #3
sourdough
Montana Master
 
Join Date: Mar 2020
Location: Lamesa
Posts: 621
M.O.C. #26010
The sail switch doesn't allow the furnace to ignite;

"The sail switch works by sensing the airflow. If there is an insufficient amount, the switch will prevent the furnace from igniting and the fan will be running but you will get no heat. It typically operates through the use of a paddle which gets displaced due to the force of fluid moving past it."

Have you put any kind of "restrictors" on either the intake or exhaust side of the furnace...including insect screens? Does your control board give you any indication of the problem? Once heating the high limit switch can cut the furnace off if it gets too hot but not generally in 3 minutes. Does it continue over and over or eventually quit and you have to reset? I've had the exact problem you describe and it was the control board. Neighbor moved in with a new Cougar last week experiencing the same problem; he described it as short cycling; control board - he kept hitting reset daily until it was replaced.
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Danny and Susan wife of 55 years
2019 Ram Laramie 3500 6.4 4x4 CC 4.10 SRW
2020 Montana High Country 331RL
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