Troubleshooting a thermostat
The thermostat screen has gone blank.
A dark screen almost always means it has lost power. Start with the batteries and the breaker.
Before you call anyone
A dark screen: check, understand, then stop
Work down in order. Blue is yours to check; red is where you stop.
Safe to check yourself
Check these first
From Carrier's advice to owners.
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Source: Carrier, Common Thermostat Issues, checked 2026-10-22.
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Source: Carrier, Common Thermostat Issues, checked 2026-10-22.
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Source: Carrier, Common Thermostat Issues, checked 2026-10-22.
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Source: Carrier, Common Thermostat Issues, checked 2026-10-22.
Worth a visit from us
What it usually means
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Power isn't reaching it
Breaker on, pan dry, still dark: Carrier's advice at that point is a professional.
What we do: We trace the power from the panel to the thermostat wire by wire.
Source: Carrier, Common Thermostat Issues, checked 2026-10-22.
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Loose wiring, or a thermostat at the end of its life
Loose wiring, or a thermostat that needs replacing, can stop it starting the system.
What we do: If it's time, we fit a new one and set it up with you.
Source: Carrier, Your Guide to a Furnace Not Turning On, checked 2026-10-22.
Stop, and call
When to stop and call
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Frayed wiring, a burning smell or codes that keep coming back
Carrier's red flags: stop troubleshooting and call a professional. Don't try to bypass an error code.
Source: Carrier, Common Thermostat Issues, checked 2026-10-22.
Tell us what it's doing. We'll take it from there.
Call and describe the problem: the noise, the smell, the room that never warms up. Or book a visit online.
