“Is it the thermostat, or is it the furnace?” When the heat doesn’t come on right in the fall, that’s the first question a lot of folks around Stigler ask us, and it’s a fair one. The thermostat is the only part of the system most people ever touch, so it gets blamed first. Sometimes it deserves it. More often it’s just the messenger, and a few quick checks will tell you which.
Homes around Stigler run the full range: older houses in town with a basic thermostat that’s been on the wall for decades, newer homes with a heat pump and backup heat strips, and places out on the county roads heating with propane. These are the questions we hear most once the weather turns.
When the Screen Is Blank or Acting Strange
Why is my thermostat screen blank?
Start with the batteries if your model uses them. If it runs on power from the system instead, a blank screen means it has lost that power, and the cause is usually back at the furnace or air handler: a tripped breaker, a service switch turned off, a door panel bumped loose so its safety switch is open, or a small fuse on the control board that blew. Some systems also have a float switch on the condensate drain that cuts power when the drain backs up. That’s a leftover from air conditioning season that can still catch you in October.
Why did my Wi-Fi thermostat forget everything after the power went out?
Some models drop their network connection or schedule when the power blinks. Reconnect it to Wi-Fi in the app and check the schedule. If it keeps happening without a power outage, the thermostat may not be getting steady power from the system.
When It Says “Heat On” but Nothing Happens
I switched from cool to heat and nothing happened. Is it broken?
Give it five minutes. Many thermostats have a built-in delay that protects a heat pump’s compressor, and furnaces take a minute to start up before the blower comes on. Make sure the mode says HEAT and the setting is a few degrees above the room temperature.
The thermostat says it’s heating, but the air is cold. Which part is the problem?
If the blower comes on when the thermostat calls for heat, the thermostat is usually doing its job, and the problem is in the furnace or heat pump: a dirty flame sensor, a clogged condensate drain, an overheating shutoff, or a refrigerant problem. Note anything you see, like a blinking light on the furnace control board, and give us a call.
Why does the heat run for a couple of minutes and then shut off?
That’s short cycling. A thermostat in afternoon sun or right next to a supply register warms up fast and shuts the system down early. A furnace that’s overheating on a dirty filter, or one that’s simply too big for the house, does the same thing. Changing the filter is the easiest first check.
Smart Thermostat Questions
Can I put a smart thermostat on my system?
Usually, but check two things first. Most smart thermostats need a common wire, called a C-wire, for steady power, and plenty of older homes don’t have one at the thermostat. Without it, some models borrow power in ways that make the system click on and off. Second, heat pumps, two-stage furnaces, and dual-fuel systems each have to be set up correctly in the thermostat’s settings, or they won’t run the way they were designed to.
I installed a new thermostat myself, and now the heat pump blows cold in heat mode. What happened?
Almost always the reversing valve setting. Heat pumps use an O or B wire to switch between heating and cooling, and the thermostat has to be told which one your system uses. If it’s set backward, the system cools when you ask for heat. It’s a settings change, not a repair.
Will a smart thermostat lower my bill?
It can, mostly by not heating an empty house. With a heat pump, keep the setbacks small. A big jump in the morning can bring on the backup heat strips, which cost far more to run than the heat pump itself.
Placement and Settings
My thermostat says 70, but the house doesn’t feel like 70. Why?
Look at where it’s mounted. Sunlight, a nearby lamp, a supply register, or kitchen heat can make it read warm, so the rest of the house runs cold. A draft coming through the wire hole in the wall can make it read cold, so the house runs warm. Sealing that hole behind the thermostat with a little putty fixes a surprising number of these.
Should the fan be on AUTO or ON?
AUTO for most homes in winter. ON keeps air moving through the filter, but between heating cycles it blows room-temperature air that feels drafty, and on older blower motors it adds to the electric bill.
Do I need a new thermostat when I get a new system?
Often. Two-stage and variable-speed equipment works best with a thermostat that can control those stages, and some systems use their own matching thermostat. We’ll tell you whether your current one can do the job. If you’re retiring an old round dial thermostat, it may hold a small glass bulb of mercury, so it shouldn’t go in the household trash.
🛠 What we do: when the thermostat is the suspect, we check voltage at the thermostat and at the control board, make sure every wire lands where it should, and test the calls for heat, cooling, and fan right at the equipment. In a few minutes that tells us whether it’s the thermostat, the wiring, or the furnace or heat pump, so you don’t buy a new thermostat to fix a furnace problem.
Heat You Can Count On in Stigler
Clark HVAC is a family-owned, licensed and insured HVAC company based in Spiro, and we work in Stigler and across Haskell County. Thermostat, furnace, or heat pump, we’ll tell you plainly what’s wrong and give you the price before any work starts.
📞 Call Now: 918-839-3734
Straight answers. Fair pricing. Clean work.