Why is My Heater Not Working When the Thermostat is on?

Most of the world thinks of Phoenix, they envision a hot, dry desert city. What they don’t see is how brutal our winters can be. And there’s nothing worse than coming home on a cold day to a heater that’s not working.

It can feel even worse than the thermostat will work, but not the heater. If this has ever happened to you, here are a few reasons it could be happening.

(Quick note: We normally refer to the heater as the furnace, but in this blog post, we will use the terms interchangeably.)

The Furnace is On, but Not Heat is Coming Out

Furnaces are a lot different than the used to be. We would say one of the best improvements is that they’re much safer than heaters of the past.

The only problem with this is that furnaces made after the 1990s have many safety censors that can shut down the system. We’re grateful for the safety switches. They’ve saved families from carbon monoxide poisoning, fire, and other furnace related issues.

Despite this, they can be confusing for some homeowners. For example, did you know that when a safety sensor is triggered only a professional HVAC tech can reset the system?

Some of the issues that can trigger a safety sensor are:

When a safety switch is set off, it turns off the entire system. While your thermostat will still be up and running, your furnace is down for the count.

When this happens, it’s always best to call your local HVAC company to have everything looked at and reset if needed.

Could Gas be the Reason Your Thermostat Working, but the Heater Isn’t?

Nearly every single furnace in the United States needs natural gas, water, and electricity to be fully operational. You home is equipped with a line that pulls natural gas from a city supply.

The reason you have this line isn’t just for your furnace. Gas is pumped into your home so that other appliances can use it as well. Your water heater, clothing dryer, and dishwasher are a few examples.

When it comes to gas, a stuck or broken gas valve or control board could be the reason you’re only getting a response from the thermostat.

If you suspect the gas line of being the problem, there’s a very easy way to test this. Just turn on the burner if you have a gas powered stove. When the burner turns on it means there’s a problem with the furnace. However, when a burner won’t turn on it means there’s a problem with your gas line.

The Furnace Needs Maintenance Work Done

Scheduling twice yearly tune-ups are one of the best things you can do for your HVAC system. We recommend two tune-ups per year. Once in the spring for the AC and once in the fall for the heater.

At Proskill, a furnace tune-up is much more than a simple tune-up. Our technicians make sure to inspect, clean, and test every part of your system to make sure there are no big fixes lurking around the corner.

When was the Last Time You Changed Your Air Filter?

Second to scheduling regular tune-ups, the next best thing you can do for your HVAC system is to routinely check and change or clean the air filter.

Air filters play two important roles. First, they keep dust and other debris from settling in your HVAC system. And second, they trap dust, dander, allergens, and other airborne contaminates.

This means that no matter how strong your air filter is, it will need to be cleaned or replaced. Air filters get full, that’s how you know it’s working. You need to change the air filter because a clogged filter can make your heating bills go up and keep your air dirty.

When an air filter is clogged or overfull, it blocks clean, warm air from coming through. Instead, the HVAC system needs to work twice as hard to produce the same amount of air. And that air may not even make it into your home.

Is Your Furnace Short Cycling?

Your HVAC system runs on a cycle. Meaning that every time your system works to heat or cool your home, it’s going through a series of cycles.

A cycle starts when your thermostat sends a signal to the furnace that the house needs to be a few degrees warmer. The furnace then pulls in air from your home, heats the air, and sends it back. This is a cycle. It usually takes 15-20 minutes for a cycle to complete and for your home to reach the desired temperature.

This all works well until it doesn’t. Your furnace can short cycle, meaning it can’t complete a full cycle. Some other reasons your furnace will short cycle are if:

  1. The furnace itself is overheating
  2. The air filter is too dirty and too full of debris
  3. Your flame sensor isn’t working
  4. The thermostat is in the wrong spot
  5. Your Furnace is too big for your home

Looking for the best HVAC service in Santa Phoenix? Look no further than Proskill. To schedule an appointment, call the number at the top of the screen or click here to book online.  

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