RV Furnaces are designed for a SPECIFIC RPM motor for its BTU rating. Using a FASTER RPM motor is ill advised and could be dangerous. The orifice of the burner tube is designed to discharge a certain volume of LP gas to MIX with a certain volume of fresh air to get the CORRECT ratio to burn CLEAN. Not enough fresh air, it will burn RICH. TOO MUCH air and it will burn lean. So, in this case it will burn lean and will not heat properly and may not even stay lit or even light. It may push the flame away from the sensing electrode. Doug
