Edmond Air Conditioning, Heating and Plumbing

If you have a gas furnace as many of us do in Oklahoma, you have a heat exchanger. This portion of your heating system is heated by the open flame that is inside your unit. It is porous, allowing air to pass through it, similar to a radiator. Cool air passes through it is heated by the heat exchanger and then passed along to your vents. I think just about everyone has had to relight their pilot light at one point or another because the air coming out of their vents was cold. That pilot light is what ignites the furnace portion and heats the exchanger.

Sometimes the heat exchanger cracks or even rusts with age. Newer units have safety mechanisms in place that account for this, but it's usually the older units that time is catching up to. Many of these units predate current safety mechanisms to account for heat exchanger issues.

What can happen from a faulty heat exchanger?

First, a cracked exchanger can allow the exhaust gases from your open flame to mix with the air passing through the exchanger. This ultimately leads to carbon monoxide, an odorless killer, blowing out your vents. If left unchecked, the exchanger can actually leak enough carbon monoxide to be deadly.

Second, the heat exchanger can have air pulse back through to the burner, causing a flame rollout. We are called out on no less than 3-5 instances per season of flame rollout. This is a major fire hazard and a good reason to be careful of what you store next to your furnace. Any flammable substance only increases your risk.

How can I check to determine the health of my gas furnace?

Damaged heat exchangers are difficult to detect. There are carbon monoxide tests, but often it will take a scope to detect the problem. We always recommend that you have a qualified company perform the inspection. As a reminder, our Maintenance Plans offer seasonal inspections of both your heating and cooling. Many of our clients sleep easily knowing that everything is in order and their families are safe.

Every so often we see a story on the news about lives lost due to carbon monoxide poisoning. Each time our heart skips a beat because we have to wonder if loss of life could have been avoided. In many homes, the HVAC system is very likely the culprit of carbon monoxide poisoning. That’s why it’s so important to have your HVAC unit inspected both in the summer and the winter. Sure you can check both aspects in one visit, but breaking it up into an AC tune-up in the spring and a heater tune-up in the fall allows us to catch major issues much quicker. Something as simple as a bird nest built over the summer could block the exhaust, causing it to back up into your house. It’s true that you can smell natural gas due to an additive that the local gas company injects into the supply that you can actually smell, but that doesn’t apply to the exhaust fumes because the additive has already been consumed in the ignition process. Other likely issues include storm damage to the vent cap on the roof or wear and tear on the exhaust fan motor causing it to seize. All units should have a safety system in place to detect unsafe situations and stop the system from operating, but even these can fail from time to time, especially in older units.

Besides having your heater serviced on a regular basis, it’s important to have adequate coverage in your house of carbon monoxide sensors. It’s especially important to have them near bedrooms and for the best detection, keep them at the same height as you are when you are sleeping. The most common myth is that they should be placed high next to the smoke detector. Smoke rises, but carbon monoxide doesn’t. It mixes evenly with the air, so the most logical point of detection is at nose level. There are units that actually plug into an outlet which can be good, as you don’t have an issue with dead batteries. To cover all situations, though, purchase both types so you still have protection in a power outage. A good habit with both fire and CO sensors is to change the batteries in the fall regardless of whether they need it or not.

As a reminder, we offer a worry-free maintenance program that includes a spring and fall checkup designed to catch issues throughout the year before they can cost you more in repair bills or worse, loss of life. Perhaps we are being a little dramatic, but then again, maybe this friendly reminder will save a life!