Why would a stuck sequencer cause the furnace blower to operate continuously?
63-10) Explain how a stuck heating sequencer can keep the fan operating continuously. The fan points on the sequencer stick as well as the points to the heater. Time delay relays that control individual strips and all in one sequencers that control all the strips and the blower motor.
How do you know if a sequencer is bad?
The Signs a Furnace Sequencer Is Bad Your heating elements may not turn on at all, and then the furnace won’t be able to heat your house. It’s also possible that the sequencer will lose control over the coils so that they all come one at once. When that happens, the circuit breaker will probably trip.
Why does my furnace keep starting and stopping?
This behavior is caused by something cutting short each furnace cycle since your furnace is being forced into a short cycle to keep your home the temperature set on your thermostat. Serious furnace problems can lead to malfunctioning, and cause furnace repairs if your furnace keeps starting and stopping.
What causes a heat sequencer to fail?
Several issues can contribute to the failure of this part: Frequent use throughout the season causing flexing and straightening of the bimetal switch. Control voltage is applied to the heating coils which heats the bimetal switch. This is essentially a thermostat which rises when heated.
Why does furnace fan run continuously?
If your fan limit switch is set to AUTO but the fan continues to run without ever stopping, you’ll need to call a professional. Two problems that could cause your fan to run without stopping include: A bad fan limit switch that needs to be replaced. Bad thermostat wiring.
What does a furnace sequencer do?
What’s the Sequencer? The sequencer is essentially a series of conduits that prevent the voltage from entering the electric furnace from turning on all the heating elements at one time. The heating elements are the electrical coils that warm up as electricity passes through them; they’re what actually heats the air.
Why won’t my furnace shut off?
If it’s cold, that means that your furnace is not running but the air handler is still blowing air. If the air that the furnace is blowing is hot, that means that the furnace burners aren’t turning off. Two very common causes are that the thermostat is set too high, or the filters being dirty.
Why is my furnace short cycling?
A dirty air filter is the most common cause of short-cycling. If your air filter is clogged with dirt, it won’t allow proper air flow to the heat exchanger. That can cause the furnace to overheat and forces the high limit switch to ride to the rescue by shutting the furnace off.
How much does it cost to replace a heat sequencer?
Electric Furnace Sequencer Replacement (Heat strips rarely fail.) Sequencers can have a life expectancy of 12-15 years. A sequencer replacement for an electric furnace typically costs around $300.
Why does my furnace fan not shut off?
If your furnace fan won’t turn off, you most likely have one of these 3 problems: Your furnace fan limit switch is set to “manual override” The fan limit switch is faulty and needs to be replaced. There’s a problem in your thermostat wiring.