Stove has been acting strange. It fires up with no problems and when it reaches temperature the blower comes on. However, after about a minute of running, the blower shuts off for a few seconds and comes on again and it remains on. When the stove is shutting down, the blower blows out heat and will shut off when its cool enough. However, it comes back on for a minute and then shuts down again, This may happen two or three times until it shuts down for good. Any ideas?