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What to do when your heater's temperature isn't hot enough

What to do when your heater's temperature isn't hot enough

Furnace Not Warm Enough? Here's What the Problem Might Be.

Even if your heating system is fairly new, things can happen to cause your HVAC unit to malfunction. One of the more frustrating problems is when you heater fan comes on, but no hot air comes out. Other than being out of fuel, this problem comes down to one of three issues: electrical failure, mechanical failure, or a faulty pilot light. In some cases it may be a simple fix, but you should contact a local HVAC company in Brenham to have the problem properly diagnosed ASAP, especially in northern climates during the winter months. Here is an explanation of the three reasons why your heater is blowing cold air.

Electrical Issues That Cause Heater Malfunctions

Most newer HVAC systems use electronic components to control most functions, which can cause problems with thermostat and ignition controls. Electrical-related problems include:

  • Incorrect Thermostat Setting - You are having “thermostat wars” with other people and someone turned the thermostat's fan setting to “On.” This will cause the fan to run continuously, whether the burner is lit or not, causing the fan to blow without producing heat. Switch the setting back to “Auto” and the problem should be resolved.
  • Incompatible thermostat - If you had a new thermostat installed recently it could be that the brains of the new unit are not compatible with your HVAC system.
  • Weak batteries in the thermostat - Try new ones.
  • Computerized control issues - Most newer HVAC systems are equipped with an electronic control panel. The panel could be faulty or the system just may need to be rebooted. Try turning the system off, via the power switch, and then back on after waiting a few minutes. This is basically just like rebooting your personal computer when it's acting buggy. If the unit still blows cold air call your HVAC company in Brenham.
  • Faulty electronic ignition - A newer system with an electronic-ignition module may be the culprit if you are experiencing an intermittent ignition, This may be an indication your system needs an adjustment or a replacement of failing components.
  • Fuel-supply issues.- Even if you have fuel in the tank you could still be dealing with a fuel-supply related problem, such as the fuel is not getting to the burner. If you are hooked up to a gas-supply line check with the supply company to be sure they aren't having issues with delivery. If you have fuel reaching the burner there are several other mechanical issues that can cause your heater to blow cold air:
  • The fuel valve is closed - The valve switch needs to be in the “on” position, set parallel with the fuel line or gas supply pipe. Of course, if you have an electrical heating system this isn't an issue.
  • The fuel pump is not functioning properly.
  • A clogged fuel filter, preventing fuel from reaching the burner.
  • A clogged air filter, preventing air from reaching the combustion chamber or causing the furnace to overheat, shutting down the burner.
  • A faulty thermocouple sensor not allowing the pilot light to remain lit.
  • Dirty fuel burner - If the burner itself hasn't been serviced in longer than you can remember it may just need a good cleaning, as rust, dirt and other types of buildup can clog the burner jets, preventing a fame from being established. A professional cleaning may solve the problem.

Other Causes of Heater Problems

Many newer units have electronic ignitions, and not pilot lights. However, if you have an older unit with a continuously-burning pilot the light may have simply gone out. The pilot light functions by throwing a small flame onto a thermocouple, that expands from the heat of the flame and keeps the gas value to the burner open. When the thermocouple doesn't receive heat from the pilot light the thermocouple contracts and shuts the gas valve so the furnace can’t ignite. This is actually a safety mechanism, to prevent gas from building up and causing an explosion.

  • Pilot lights can sometimes be extinguished from an errant gust of wind near the furnace, from a door or window being left open or someone working near the unit. Faulty pilot lights can be related to either electrical or mechanical failure, depending on the design of the pilot. When a pilot light fails it is typically the cause of a compromised flame sensor.
  • If your heater starts up and begins blowing hot air, but suddenly that air turns cold, the flame sensor is probably guilty. Like the burner, the pilot's flame sensor may just be dirty, or it may have just reached the end of its lifespan, causing the burner to keep going out. Of course, this could also be electrical related if your system has an electronic ignition.
  • If your unit isn’t blowing hot air at all, and it is over 20 years old, it may be time to think about a new system. Still, many causes of HVAC problems are easily prevented by having your system regularly serviced. If you haven’t had your system serviced yet this year, or in many years, call in an HVAC service expert to be sure your unit is in top shape to prevent any unexpected problems.

For professional HVAC services in Brenham, TX, call Plumb Level at (979) 200-6674.


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