Whenever you detect a mysterious smell, the first place to check out is your HVAC system.
This is just as true with a large commercial HVAC as it is with a small home air conditioner.
There are many different opportunities for an HVAC system to emit a strange odor. However, that doesn’t usually mean that there’s a mishap within the commercial compressor unit itself.
The commercial compressor functions as the heart of the system, doing the necessary mechanical work to make refrigerant gas available to all the other components. When other parts of your HVAC run into a problem, the compressor has a limited ability to work harder to make up the difference.
But when the compressor fails, the rest of the system stops cold.
Understanding this, you might think that the compressor is the natural first place to look for an issue. But most modern compressors will last anywhere from eight to ten years with appropriate service. They regularly outlast other parts of the system – and that’s good since they can be costly to fix.
Let’s look at how your commercial compressor relates to the smell of your HVAC.
The Rare Case When Compressor Performance and HVAC Smell May Be Related
There are lots of different odors that can emerge from your HVAC, so the first thing to do is ask some questions about what’s going on. No matter what kind of building you’re dealing with, you might need to get information from people who work or live around the “smelly” area.
Here’s what you need to know:
- What does it smell like?
- Where has it been detected?
- Is it noticeable only when the system is on?
- Is it noticeable only in cooling or heating mode?
- Is it getting stronger or weaker?
The compressor operates directly on the refrigerant gas in a cycle that repeats several times each day. Like so many industrial chemicals, the refrigerant gas is often infused with extra agents that add an artificial smell so personnel can notice when a leak takes place.
For the most part, refrigerant gas smells sweet. It may also have a strong chemical odor that has been compared to chloroform. If your mystery smell matches either of these descriptions, then there is a possibility that your compressor is involved in the issue.
To figure it out, you should visually inspect the compressor and its operating environment. If nothing is amiss with the unit itself, then start tracing connections to search for leaks. If there is a leak somewhere in the system, you will be losing refrigerant rapidly and may soon be blowing lukewarm air.
Why the Compressor Usually Isn’t the Source of a Mysterious HVAC Smell
Most of today’s commercial HVAC compressors are designed using a semi-hermetic architecture. This means that the compressor and the motor are sealed off from the operating environment, but you can access them whenever you need to perform maintenance or do repairs.
Because of the tight seal between the compressor and the outside environment, it is actually very rare that any scent will come directly from the compressor itself. After all, to smell anything, microscopic particles need to be spread from the source to your nose and olfactory nerves.
If any chemical, liquid, or dirt enters the compressor’s enclosure, then there’s a chance you may smell it as long as the seal is not completely tight. And under rare and hazardous circumstances, you may smell a “burning” odor if there’s an electrical short somewhere in your system.
But for most smells, you’ll need to look elsewhere for the root cause.
The Most Common Source of Unknown HVAC Smells
Indoor air can be surprisingly polluted, so there’s no “one size fits all” solution for smells. When it comes to a large commercial or industrial HVAC system, though, the most common issues are twofold:
- Dirty air filters that are past their replacement or cleaning date
- Clogged ductwork with smells caused by the obstruction itself
Of the two, air filters are by far the more likely concern. Commercial HVAC air filters are often changed every quarter, and they can start to smell rank after just a few days of missing this benchmark. With that in mind, it’s often hard to pinpoint the exact filter that’s causing the mess.
That said, older construction with narrow ductwork can have problems at any point in the maintenance cycle, even when air filters have been carefully maintained. This is most noticeable in historic buildings where required upgrades to building systems have been waived due to cultural value.
Your commercial HVAC compressor plays an essential role in ensuring airflow is sufficient to keep a building ventilated. When it’s time to replace a compressor, a remanufactured commercial compressor delivers the output and environmental performance you can count on at a fraction of the cost.