Since 2016, I've been a residential and light commercial HVAC tech. I've made plenty of mistakes—some expensive, some just embarrassing. This FAQ is a collection of the questions I get asked most, along with the lessons I learned the hard way. If you're a dealer, installer, or building owner, I hope this saves you from a few headaches.
- Is Mitsubishi Electric R-410A still relevant in 2025?
- Why is my Mitsubishi Electric mini split not heating?
- What does an oil pressure sensor do on HVAC equipment?
- Frigidaire ice maker not working – should an HVAC tech fix it?
- Ecobee vs Nest thermostat – which one should I install?
Is Mitsubishi Electric R-410A still relevant in 2025?
Yes, but you need to plan around it. R-410A is still the most common refrigerant in Mitsubishi Electric systems already in the field, but the EPA's AIM Act is phasing down HFC production. That means R-410A will get pricier and eventually scarce for new installs. New systems from Mitsubishi Electric are moving toward R-32 and other lower-GWP options. My initial instinct was to stockpile R-410A cylinders. That was a mistake—by 2024, I had spent way too much on inventory while the market shifted. What I should've done is spend that money on R-32 recovery machines and training. Lesson: don't get caught holding old refrigerant in a changing market. Verify current regulations at epa.gov before making big purchasing decisions.
Why is my Mitsubishi Electric mini split not heating?
I've been to more than a few service calls where the answer was embarrassingly simple. Check the remote first. One customer had the unit in cool mode and thought heating was broken. Another had the setpoint at 64°F. After that, look for the basic stuff: dirty filter, blocked airflow, ice buildup on the outdoor coil. If those are fine, you're probably dealing with a refrigerant leak or a faulty reversing valve. On a Mitsubishi Electric mini split, the outdoor unit usually flashes a code if the system is low on refrigerant or if a sensor fails. Don't assume the worst—read the manual before ordering parts. I once ordered a new expansion valve when the actual problem was a loose thermistor wire. Check the obvious first, and you'll save yourself a callback.
What does an oil pressure sensor do on HVAC equipment?
Oil pressure safety switches protect compressors from running without proper lubrication. If the sensor detects low oil pressure, it shuts down the compressor before it locks up. This sensor is more common on commercial refrigeration and larger heat pumps, but I've seen a few residential units with them. My worst mistake with an oil pressure sensor: I condemned a compressor because the sensor kept tripping. I replaced the whole thing, and the new compressor had the same issue. Turns out the sensor's wiring was corroded, causing an intermittent short. Now I always test the wiring and verify the actual oil level with a manual gauge before touching the compressor. And never bypass the safety—I did that once many years ago, and it destroyed a brand new condensing unit. That was a $3,200 lesson.
Frigidaire ice maker not working – should an HVAC tech fix it?
Usually no, but it comes up because we're already in the house. A customer asked me to look at their Frigidaire ice maker while I was repairing a furnace. I suggested replacing the water inlet valve without checking anything else. That wasn't it. The real issue was a clogged water filter. My $90 part didn't fix it, and I ended up losing trust with that customer. Now I keep a simple checklist: water supply on, filter not overdue, freezer temp between 0–5°F, and the ice maker arm isn't stuck. If all that's fine, then I'll suspect the valve or auger motor. If you're not a refrigerator tech, it's okay to hand off that part of the job. Sticking to what you know saves you and the customer.
Ecobee vs Nest thermostat – which one should I install?
I've installed a ton of both, so here's my honest take. Ecobee's big strength is the remote sensors. If you've got a room that's always hot or cold, Ecobee lets you use average temperature across rooms. Nest is a little simpler to operate and has a nicer physical design. For my customers, I lean toward Ecobee when they have zoning or balancing issues, and Nest when they just want a straightforward smart thermostat. But check compatibility first: both need a common wire to run high-efficiency heat pumps reliably. Energy Star says a properly configured smart thermostat saves around 8% on heating and cooling bills—but only if the schedule actually matches the homeowner's routine. Neither thermostat is perfect for every house. Match the thermostat to the home, not to what's trending.
