If Your Rheem Furnace Isn’t Working, Start Here
When your Rheem furnace stops working, especially in the middle of winter in Steubenville, it can feel like an emergency. Cold rooms, strange noises, blinking lights—you want answers fast. But before you call a technician, there are several Rheem furnace troubleshooting steps you can try on your own.
As a 20-year HVAC veteran servicing Rheem systems throughout Eastern Ohio and the upper Ohio Valley, I’ve helped hundreds of homeowners fix these exact issues. We service and install Rheem furnaces in Steubenville, Wintersville, Toronto, and Mingo Junction, Ohio, as well as Burgettstown, PA, and Weirton, WV.
In this article, I’ll walk you through the 10 most common Rheem furnace problems we see and what you can do to fix them yourself—before picking up the phone.
1. Rheem Furnace Won’t Turn On
This is the most common complaint we get.
What to check:
- Is the breaker tripped?
- Is the furnace power switch off?
- Are thermostat batteries dead?
Try this:
- Reset the breaker
- Flip the power switch
- Replace thermostat batteries
When to call: If none of that helps, it may be an issue with the ignitor or flame sensor.
2. Rheem Furnace Blowing Cold Air
Cold air coming from your vents? It could mean your furnace is failing to ignite.
Check:
- Thermostat fan setting (set to AUTO)
- Dirty air filter
Other causes:
- Faulty ignitor
- Dirty burners
3. Rheem Furnace Keeps Shutting Off (Short Cycling)
Short cycling wears out your furnace faster and makes your home less comfortable.
DIY fix:
- Change the air filter
- Open all vents
Potential system issues:
- Bad flame sensor
- Pressure switch malfunction
- Furnace is oversized for your home
4. Thermostat Isn’t Controlling Heat Properly
Inconsistent temperatures or unresponsive thermostat?
Check this:
- Batteries
- Wi-Fi signal (for smart thermostats)
- Proper settings (HEAT mode)
Pro tip: In one Toronto, OH home, the problem was a smart thermostat not properly configured to communicate with a Rheem Prestige modulating furnace. Once paired correctly with EcoNet, the system ran smoothly.
5. Rheem Furnace Making Loud Noises
Bangs, rattles, and whistling usually point to airflow or mechanical issues.
Homeowner fixes:
- Tighten loose panels
- Replace air filter
Other causes:
- Blower motor imbalance
- Expanding ductwork
6. Rheem Furnace Diagnostic Light Keeps Blinking
Rheem’s PlusOne™ Diagnostics can tell you a lot—if you know how to read it.
What to do:
- Look up the blinking code in your manual or online
Call a tech if:
- You see codes for ignition lockout, high limit switch, or pressure switch fault
7. Rheem Furnace Runs Constantly Without Heating Well
A constantly running blower that doesn’t heat can drive up your energy bills.
Check for:
- Dirty filters
- Closed or blocked vents
- Oversized furnace or undersized ducts
8. Rheem Furnace Smells Bad When Running
Odors can signal serious issues.
Normal: Dusty smell during first startup of the season
Concerning:
- Musty: Possible mold in ducts
- Burning plastic: Potential electrical problem — shut off and call a pro
9. Water Leaking Around Your Furnace
Only high-efficiency Rheem furnaces produce condensation.
Check this:
- Is the drain line clogged?
- Is the trap full or disconnected?
True story: We responded to a water leak in Mingo Junction where a new water heater install had bumped the condensate line loose on a Rheem 96% furnace. A quick fix, but easy to overlook.
10. Rheem Furnace Blower Works But No Heat
Air is moving, but there’s no warmth?
Possible issues:
- Faulty ignitor
- Flame rollout switch tripped
- Gas valve failure
Check your thermostat and diagnostic codes first.
When to Call Honest Fix for Rheem Furnace Repair
If you’ve checked your breakers, filter, thermostat, and diagnostic light and the issue persists, it’s time for a pro. Rheem’s safety controls often shut the system down when something is wrong. Continuing to run it may cause bigger problems.
Our Comfort Guides at Honest Fix don’t upsell. We inspect your system, explain the issue clearly, and give you real options with transparent pricing.
Give us a call when you’re ready for real answers and real solutions.
Alex Largent
Alex Largent is the Owner and Senior HVAC Efficiency Analyst at Honest Fix Heating, Cooling & Plumbing. With more than 20 years of field experience, NATE and EPA certifications, and a hands-on leadership style, Alex teaches his team to fix systems right the first time — with transparency, precision, and no upsells. He writes about HVAC diagnostics, home energy efficiency, and practical maintenance advice for homeowners across the Upper Ohio Valley. Read Alex Largent’s full bio to learn more about his expertise in the HVAC and Plumbing industry. Updated October 2025.
