What Are The Signs That My Furnace Needs Attention?

October 24, 2019

Why Will My Heat Not Come On?As the temperatures drop in the fall, it’s time to kick on the heating side of your HVAC system.

Why Will My Heat Not Come On?

  • Confirm the set point on thermostat is higher than the current temperature in your home
  • Confirm the furnace in the attic is turned on
  • Confirm the gas is turned on to the furnace

If none of the above solve the issue, call out an HVAC tech.

Why Is My Heater Only Blowing Cold Air?

This suggests there is an electrical issue within the system and your system is only running the blower fan.

Why Is There A Loud Rattling Sound When The Heat Is Running?

When you have a gas system the unit will emit some noise when running. Typically, it is a soft roar. If you have a heat pump unit, you should hear the same sounds from the fan running as you would when the AC is on coming from the closet. If there is an excessive amount of noise, there is more than likely a problem. A lot of rattling indicates something could be loose in the burner assembly, a mounting bracket has broken, a loose connection on the flue pipe or a motor bearing is wearing out just to name a few.

The condition will only worsen if not attended to and is a sign that there is a failure of the component on the way.

Why Is My Heat Shutting Off Before It Reaches The Set Temperature?

Why Is My Heat Shutting Off Before It Reaches The Set Temperature?

There are several potential reasons as to why your heat is shutting off before it reaches the preferred temperature. Reasons could include:

  • Thermostat is out of calibration or has an internal fault
  • Limit switch within the furnace being tripped
  • Restriction in the flue pipe
  • Motor is failing to maintain a vacuum
  • Loose or defective safety switch
  • Sensor inside the ductwork may be triggering a high limit and shutting system off

If there have been any electrical outages in the area or lightning strikes, it may have impacted the control board/s with the furnace, thermostat, zoning controls, or dampers.

Why Am I Getting a Headache or Feeling Nauseous When the Heater is Running?

Why Am I Getting a Headache or Feeling Nauseous When the Heater is Running?When the furnace is running, it is burning gas and giving off carbon monoxide. This operation is contained inside a heat exchanger with carbon monoxide being pulled out of the heat exchanger and vented through the flue pipe. Carbon monoxide leaks can occur from several things including:

  • A heat exchanger can crack, allowing it to leak
  • Age of the unit could cause it to start rusting out and developing holes
  • A joint in the flue pipe has come apart, or it has rusted and developed a hole

Carbon monoxide is a heavy gas. With it being heavier than air, it will fall. It does not have an odor and can only be detected with a plug-in alarm or a handheld tool.

Why Do I Smell Gas When The Heater Is Running?

If you smell gas when the system is running, shut the system off and call out a service technician. This suggests there could be a burner that is not lighting, there is an excessive delay before the burners are igniting, a leak in the gas supply line to the burner assembly or an electronic/ electrical issue with the circuit board causing a malfunction.

Why Does It Smell Like Dirty Socks When I Turn The Heater On?

Why Does It Smell Like Dirty Socks When I Turn The Heater On?When a furnace is started up for the first time or couple times if there is any dust or buildup in the burner assembly or on the heat exchanger this will burn off and there will be a smell given off that will come out of the ducts and be in the home for an hour or two.

If the smell persists beyond the first couple of startups, then there are potential issues If there is a dirty sock smell when the unit is running, it’s probably related to the evaporator coil either dirty or bacteria on the surface. The smell will not go away until the source is addressed.

Why Is There A Musty Or Sewer Smell At Times When The Heating Is Running?

The musty or sewer smell is from the condensate drain line when it is not vented properly. There is no P-trap to prevent smells traveling back into the unit. Also, another potential reason this smell can occur is if multiple systems are tied into one common drain line causing one HVAC system to impact another.

Why Does The Outside Unit Start Running When The Heating Is Running?

If you have a heat pump unit, the outdoor unit (condenser) will run by design. The refringent is taking heat from the air outdoors and transferring it into your home. If you do not have a heat pump (meaning you have a gas system) and the outdoor unit is running the fan and or the compressor, that could indicate there is an issue and you would need to call a technician.

How Can You Tell If You Have A Heat Pump?

Take the model number off the unit and google it, or text the picture to us and we can let you know. For example, on a Trane the model will start 4TW – the W stands for heat pump.

Why Is My System Making a Clicking Sound Like It’s Trying To Start But Doesn’t?

The noises are related to the furnace going through its startup sequence. One of the items in the sequence is not found, for example, door switches closed or flame detected. The unit will wait for a designated period depending on the unit, 45 seconds or 5 minutes then go through the startup sequence again. Furnaces typically go through 3 cycles then will go into “Lockout mode” when there has been a problem detected. Switch off the main power. This will reset the furnace and will clear the lockout. It will go back through the startup procedure again. If it goes back into the “Lockout” mode after 3 more times, there is a larger problem detected and a technician will need to be called.

Why Does My Heating System Run Nonstop and Never Shuts Off?

In Dallas if your heating system is functioning properly it will run until the temperature set point on your thermostat is achieved and shut off. However, as an exception, if it is extremely cold or below freezing, a high-end communicating system/variable speed unit will ramp up and down to meet the heating demand in your home.

A heating system should cycle on and off like your air conditioning, if it doesn’t there are many potential reasons as to why this might be occurring.

If you have high ceilings, especially great rooms the heat is rising and filling the ceiling – running ceiling fans (reversing the direction downwards) moves the heated air around the room.

If you have a two-stage furnace, there is an issue that is causing the unit to only run in the first stage roughly 70% of full capacity, the second stage will boost the heating by about 30%.

The furnace may be too small/undersized to heat the space to the desired target temperature. This can occur if there was an addition made to the home at some point and the unit was not changed to meet the demands of the added space.
If the home is 20 years old or older, the attic insulation may have compressed and is no longer giving much insulation to prevent heat transfer from the ceiling to the attic.

Ductwork Issues

There may be a supply duct that has become disconnected from the furnace and is heating the attic causing instead of heating the designated area of your home. This can occur with old ductwork losing insulation or developing holes.
Also, there may be a hole in the ductwork or metalwork between the return air from your home going to the furnace, that is pulling in cold attic air which is making the heating system work harder.

Why Does It Take A Few Minutes After My Heat Starts To Blow Out Any Warm Air?

After turning your heating on it will take up to 90 seconds for the furnace to start up and the blower fan to start moving air. If it is taking several minutes for warm air to come out of your vents and start warming the home, there could be a few reasons.

  • There may be excessive delays in the startup that can relate to a faulty circuit board
  • There may be low insulation in the ductwork, allowing the air to be cooled after the furnace
  • Potentially holes in the ductwork, filling it with cold attic air

Why Do I Or Someone In My Home Get Nose Bleeds When The Heat Is Running?

In DFW the winter air is drier the air inside your home in winter has less moisture, then heating the air removes more moisture. For some people this can result in dry skin, others have sensitive nasal passages which cause irritation and nose bleeds.

Call or text us with any questions at (469) 444-2001 or reach out to us online at www.scmdfwair.com!

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