Easily monitor, control and optimize a Lutron control system from any tablet, PC or smartphone. The fan limit switch also has two other functions. Essentially, this means that it determines when the hot air should be blown through your ventilation system. If the switch isnt working, it should be replaced. A fan limit switch is a component of a furnace system that determines when the furnace blower assembly for hot air turns on and off. This kit is designed to replace the fan control and applies to all Reznor products using a Thermodisc 29T 12-32517 fan control (Reznor P/N 10357). If youve experienced these problems, check your cooling fan and switch. Reznor 209184 - Fan Control Replacement Kit - The fan control used on Reznor heaters with a Thermocore 1 heat exchanger has been discontinued by the manufacturer. Symptoms of a faulty cooling fan switch include an overheated engine and an active Check Engine light. Lutron’s NEW facility management tool empowers you to manage your building from anywhere. Your cooling fan switch activates your fans to cool your radiator. Variable Speed Controller for VKM & VCN Electrician Required.