Is your furnace malfunctioning? Let’s troubleshoot your problem and determine the next steps.

Life is hectic, and it’s easy to take for granted everything in your home that just “works”—that is, until it breaks. A malfunctioning furnace is a nuisance no matter the time of year, but in the winter, having no heat is typically an emergency. We can help you with same day furnace diagnostic and repair service, so let’s figure out what’s wrong and determine the next steps.

As far as our rates: If it is during regular business hours, to diagnose what’s wrong with your furnace, we charge $100, plus tax. Once we’ve determined the problem and move forward with a repair, if it is during the same visit, we charge $100 per hour (broken into quarter hour increments), plus any required replacement parts and tax. If a follow up visit is required, we charge $100 for the first half an hour on site, and then the aforementioned labor rates apply.

Before we schedule an appointment, below are some common problems and potential quick fixes that may help you avoid an unnecessary service call.


Common Furnace Problems

We see a lot of the same issues when we pay our customers a visit. Here are some of the common problems we see, some with simple tips you can try that may help you avoid an unnecessary service call.

1) My Bills are Increasing

If you notice your monthly utility bill steadily rising without explanation, your system’s air filter may be too dirty. Check the filter and clean or replace it as needed. Then compare your next utility bill with the previous to see if your operating cost returns to normal. If the filter looks clean enough and your bills are nevertheless rising, it may be the case it’s simply getting colder outside or someone has set the thermostat to a higher temperature, and hence your furnace is running more. It’s also possible the utility company has raised their rates without your notice. To get to the bottom of why the bill is rising, it’s helpful to compare the rates and the usage history of your current bill with that of the same time period in the previous year or other, previous months that were the same average temperature outside. This can help you see based on real data rather than fuzzy memories whether the cost has in fact risen. If you’re having difficulty figuring this all out, give us a call and we’ll see how we can help.

2) Intermittent Operation

If your furnace works fine sometimes and other times it doesn’t seem to come on, a component in your furnace could be in the process of failing (e.g., circuit board, pressure switch, etc.). Unfortunately, there isn’t much you can do about this other than have a technician determine which component is failing and replace it.


3) Room to Room Temperature Imbalances

A classic symptom of poor ductwork design or damaged ductwork is an inconsistent temperature throughout your home. Often homeowners confuse this symptom with a furnace problem. Furnace problems typically impact the temperature throughout the entire home, not simply a portion of it. Give us a call and we can chat about potential solutions. These solutions usually involve duct design revisions or duct repairs.

4) Runs Loudly

“Runs loudly” problems can be divided into two categories, “new noise” and “always been there but I’m tired of hearing it” noise. New noise is often caused by fan bearings wearing out causing the motor to operate with more noise. This will likely require a fan replacement. If the new noise is a loud bang during start up, this should be addressed by a technician, as you may have a serious problem called “delayed ignition”. Whistling or harmonic noises may be new or old and are usually caused by just the right amount of airflow moving through the ductwork or return air grilles (similar to the right amount of airflow moving through your lips to create a whistle). These can be solved by different grille(s), duct revisions, or alterations to the existing grille(s). Old noises typically stem from too much airflow. This can be caused by a return air being located too close to the furnace, or by an oversized fan moving too much air, or by the fan speed setting being too high. Fixing these older problems can be achieved by ductwork revisions, turning the fan speed setting down (if it isn’t already on low), or, worst case scenario, by a new, quieter furnace.


5) Flipping on and off Constantly

A gas furnace that will only heat for a few minutes without reaching the temperature setting on the thermostat is usually caused by a dirty air filter. A clogged filter can sufficiently decrease the airflow through the furnace to cause the furnace to overheat. Overheating triggers a safety switch called a “limit” switch that shuts the furnace off. Sometimes it is worse than this, though–the furnace flame will ignite, but it will only stay lit for a couple of seconds. This is likely due to a dirty flame sensor (or possibly dirty burners), a component which ensures the gas has ignited after the gas valve opens during the initial ignition sequence. Cleaning the flame sensor is a standard service item we perform during a furnace tune up.

6) No Heat

Silly as it seems, first check to make sure your thermostat doesn’t require its batteries be replaced (you’ll often see a blinking battery indicator light on the thermostat display if this is required). Also, ensure the t-stat is set to “heat” and the temperature in the house is set above the current temperature. Also check to see if the electrical shut off toggle switch typically (but not always) found on the side of the furnace is in the “on” position, and ensure the breaker hasn’t tripped. Finally, if you have an earthquake shut off valve, check it to be sure someone didn’t bump it and accidentally cause it to shut the gas off to the home. If all of this looks fine and the furnace doesn’t heat, you probably have a issue that requires a service call.

The “before you order a service call” checklist:

Okay, you’re pretty sure that you need our help—but you don’t want to have overlooked a silly thing that could be causing your issue. No problem, here’s a quick list to double check.

  • Check the thermostat and ensure it is set to “heat,” and check the temperature setting to ensure it is set above the current home temperature.
  • Check the thermostat display for a blinking “replace battery” indicator alerting you to the need for new batteries.
  • Ensure the air filter is relatively clean. If dirty/plugged, clean/change the filter and reset the furnace by turning the power off and back on. If you need a new filter, we do have the common sizes available at our office.
  • Ensure the electrical shut-off switch on the side of the furnace is “on”.
  • Check the breaker box for a tripped breaker. If tripped, reset. If it flips back off, don’t try to reset it again and give us a call.
  • Ensure the utility company hasn’t shut your gas off at the gas meter (you’ll see a lock on it if so).
  • Ensure an earthquake shut-off switch on the gas line near the gas meter hasn’t tripped shutting the gas off to the home. This often occurs when someone bumps the meter when they were putting a garbage can back or mowing the lawn. There is a button on the EQ shut-off switch you can push to reset it.
  • Check to be sure the manual gas shut-off valve on the gas pipe feeding the furnace has its handle parallel with the gas pipe (parallel is in the “on” position). If the valve is perpendicular to the gas pipe, it is off. You will most likely find that it is parallel with the pipe, but if someone was working near or on the furnace, they may have shut the gas off and forgot to turn it back on.

Most furnaces built in the past 25 years have an indicator light on the furnace circuit board that indicates whether the furnace is operating correctly or is suffering from a problem. If there is a system fault, this light will blink inconsistently with slow and fast blinks communicating an error code. A steady light or consistent blinks usually means everything is fine. A written key code is usually found on the inside of the furnace door(s).

Safety First!

If your furnace needs more attention than a simple fix—give us a call. Any furnace, regardless of its age, may pose combustion or gas related safety hazards, so it’s always a good idea to have an expert examine the unit and suggest the best course of action. During our visit, our highly-trained technicians thoroughly inspect the system to diagnose any problems. Call us to schedule an appointment: 425.885.1224.


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Better Business Burearu
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Senior Discounts
Angie's List Super Service Award
Best of Redmond Award