- J.C. 4/15/2013. I don't know what's happening with your heating system but I can, from your note make a few diagnostic suggestions: Watch out: you are quite right not to force the set point adjustments on a fan limit switch. It has always done this. Am I missing something here? Check out, On 2020-12-16 The reason the fan shuts off during this process is so the system doesn't pull the cold air from the outside across the coil while the hot refrigerant circulates. it resets and works properly. So why does the downstairs get so cold when thermostat is 68 and way way too hot at 70? Pilotless furnaces have been an energy-saving breakthrough for the home and commercial heating industries. Your gas supply could be turned off. When the furnace is … New furnaces are equipped with a spark ignitor or electronic ignition, which may require a technician to repair. This winter local utility provider replaced burned out fan motor with same HP, number of speeds, etc. The furnace will be more likely to pull in sediment from the tank, which can clog your air filter. When the condensate drain freezes, it causes condensation to drip back into your system and trigger a shutdown. Ductwork is often installed in areas such as attics, garages or crawl spaces where there isn't temperature control. Unfortunately, more complex issues in this department typically require an expensive replacement. Heating up air uses a lot of energy and is financially costly. If your fan only runs when your furnace is heating the air, then you’re much less likely to experience your furnace blowing cold air. Your furnace blowing cold air could be caused by hot air escaping through holes in the duct work that carries the heat throughout your building. It has always done this. According to the book the 2 red flashes means "Retries or recycles exceeded". If you choose to call a professional to do the job for you, this would be a good time to have your system inspected. If this is the case, someone walking by the burner could generate enough of a draft to cause the pilot to go out. Ensure that your thermostat is set higher than the temperature in your home. 11. The fan setting on your thermostat has two options, “on” and “auto”. 1. Gas furnaces produce air that is 130-140°F range. A furnace that isn’t getting fuel will not ignite and will blow only cold air. Change the air filter If your furnace overheats, it could end up blowing cold air. The HSI features a cobalt element that's prone to cracking. I do not dare force it. These Common Issues May be the Reason, AC Evaporator Coils: Everything You Need to Know, AC Compressor Not Working but Fan is Running, Evaporator Coil Leak: What You Need to Do, Looking for A Portable Air Conditioner That Doesn’t Need A Window, Why Your Furnace is Short Cycling and What to Do About It, Best 50 Gallon Electric Water Heaters: Our Top Picks. However, the fan will keep running, cooling the furnace to protect it from potential damage. Although you can do this yourself, we recommend calling a professional as there may be another underlining problem. They are available in electric, gas and oil models. The condensation must be removed from the system and if your condensate drain terminates outside your home, it can freeze. Changing set points on limit switch does not seem to change pattern. Heat pumps are a different beast altogether. Such leaks not only increase heating costs unnecessarily, they also are unsafe. If your pilot light did go out, try to relight it. Check to see if one of these troubleshooting tips fixes the issue. Another telltale sign is if your utility bills are higher than they should be based on use. Help! The flame sensor itself is relatively easy to clean, but many homeowners are uncomforable working on their furnaces. Is your furnace not blowing hot air? Or the gas line isn’t supplying enough gas to your furnace. Let us know what you find as that will help others. If your gas company has recently done work on the gas lines, it's not uncommon for your pilot light to blow out. Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia. Changing the dirty air filter can solve this problem. You may also see an error message on your thermostat, or a blinking LED light on the furnace control board. At the time the furnace is blowing cold air, I see two slow green flashes followed by 2 quick red ones. Take a look at the duct system itself for things that can make it cool down quickly blowing cold air sooner than one might expect, such as a long uninsulated run, missing insulation, air leaks at the return side. Or maybe the air starts off hot, then turns cool before the furnace shuts down. Your body temperature is around 98.6°F (everyone’s body temperature is slightly different, but that’s the average). If you find that you go to bed comfortable and wake up freezing because instead of your heater delivering warm air, it's blowing cold, it might be because the condensate drain has frozen. Once every few days, the furnace will kick on as normal, send out heat, but after a few minutes weâll notice that itâs blowing cool air. Unfortunately, it isn't uncommon for an HSI to malfunction. If the flame sensor is dirty, your furnace will turn on and begin heating but then turn cold … You might be suprised to learn that one of the most common residential HVAC issues is the thermostat. Possible Conclusion 1: It’s Not Blowing Cold Air. Recent information. Leaky ductwork can cause serious issues for your heating system. Your furnace clicks on and the blower motor is running, but the air coming from the vents is cold or cool instead of hot. An HSI or Hot Surface Ignitor is the most popular way to ignite a pilotless furnace. A dirty furnace filter is the root cause of many problems. As a pilotless burner owner, you'll want to keep your fingers crossed that your issue isn't related to your burner's circuitry. This can be caused by something as simple as a strong draft. After checking that your fuel level is adequate and your filter is clean, the next area to check is the flame sensor. You’ve got three basic options. If you're lucky, the problem may be as simple as changing a fuse on the circuit board. The furnace fan limit switch assembly is intended to be adjusted within a safe range by the heating service tech by moving the stops, but if you bend something the switch is damaged and unsafe, and if you set the switch incorrectly (for example fan coming on too late or turning off too early, or setting the upper limit too high) there is risk of overheating the heat exchanger, cracking it, risking fatal carbon monoxide poisoning at worst, or perhaps a costly heat exchanger or furnace replacement job. Two different people worked on the 2016 repair. The major issue that can cause this problem is a heat exchanger issue. If this is the case, you can simply switch the setting from "on" to "auto" and your problem should be fixed. We have owned home 12 years. If I shut if off for a few minutes and then try again, about half the time it will blow hot air. But still the same issue. Can you say what we ought to check? Use a wrench or pliers to remove the pilot tube. Used to work fine and then during a repair in 2016 all the ducts were fully opened- my mistake. So 85-92°F feels cold to new heat pump owners. (This is just on general principle).
furnace blows hot air then cold 2021