3AFUSE – FUSE
$0.893 Amp bladed ATC fuse for HVAC control boards and low-voltage circuits. Standard automotive-style blade fuse. Protects 24V thermostat circuits and control wiring.
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5AFUSE – FUSE
$0.895 Amp bladed ATC fuse for HVAC control boards and low-voltage circuits. Standard automotive-style blade fuse. Common replacement on furnace and air handler boards.
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9-115-34-1 – FUSE LINK ASSEMBLY (FIRST CO, N951-1)
$11.84First Company 9-115-34-1 thermal fuse link assembly. 25 Amp, opens at 300°F. Ceramic body with stake-on terminals. Safety device for First Company HX coil units.
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BRK3 – RESETABLE FUSE (3 AMP)
$21.66Supco BRK3 resettable 3 Amp diagnostic fuse for HVAC low-voltage circuits. Built-in light shows when circuit is active. Resets instead of blowing — saves time troubleshooting.
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BRK5 – RESETABLE FUSE (5 AMP)
$21.66Supco BRK5 resettable 5 Amp diagnostic fuse for HVAC low-voltage circuits. Built-in light shows circuit activity. Trips and resets without blowing — great for troubleshooting.
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FUS02295 – FUSE (TRANE)
$15.10Trane FUS02295 time-delay fuse. 3.2A, 300V. Allows brief startup surges without blowing. OEM fuse for Trane furnace and air handler control boards.
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STC4228 – TEMPERATURE FUSE LINK (L235°, 15A)
$5.37Temperature fuse link, opens at 228°F (109°C). 15 Amp rated. One-time-use thermal safety device — if it’s blown, the system overheated and needs the fuse link replaced.
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STC4257 – TEMPERATURE FUSE LINK (L257°)
$5.05Temperature fuse link, opens at 257°F (125°C). 15 Amp rated. One-time-use thermal safety device — if it’s blown, the system overheated and needs the fuse link replaced.
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STC4300 – TEMPERATURE FUSE LINK (L300°, 15A)
$5.37Temperature fuse link, opens at 300°F (149°C). 15 Amp rated. One-time-use thermal safety device — if it’s blown, the system overheated and needs the fuse link replaced.
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STC4333 – TEMPERATURE FUSE LINK (L333°)
$5.28Temperature fuse link, opens at 333°F (167°C). 15 Amp rated. One-time-use thermal safety device — if it’s blown, the system overheated and needs the fuse link replaced.
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STC4358 – TEMPERATURE FUSE LINK (L377°, 15A)
$5.37Temperature fuse link, opens at 377°F (192°C). 15 Amp rated. One-time-use thermal safety device — if it’s blown, the system overheated and needs the fuse link replaced.
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STC4438 – TEMPERATURE FUSE LINK (L438°, 15A)
$5.37Temperature fuse link, opens at 438°F (228°C). 15 Amp rated. One-time-use thermal safety device — if it’s blown, the system overheated and needs the fuse link replaced.
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STC4468 – TEMPERATURE FUSE LINK (L468°, 15A)
$5.37Temperature fuse link, opens at 468°F (242°C). 15 Amp rated. One-time-use thermal safety device — if it’s blown, the system overheated and needs the fuse link replaced.
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STC5257 – CERAMIC TEMPERATURE FUSE LINK (L257°, STRAIGHT)
$17.65Ceramic temperature fuse link (straight), opens at 257°F (125°C). 15 Amp. Ceramic body for higher heat environments. Straight terminal orientation.
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STC5300 – CERAMIC TEMPERATURE FUSE LINK (L300°, STRAIGHT)
$17.65Ceramic temperature fuse link (straight), opens at 300°F (149°C). 15 Amp. Ceramic body for higher heat environments. Straight terminal orientation.
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STC5333 – CERAMIC TEMPERATURE FUSE LINK (L333°, STRAIGHT)
$17.65Ceramic temperature fuse link (straight), opens at 333°F (167°C). 15 Amp. Ceramic body for higher heat environments. Straight terminal orientation.
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STC5377 – CERAMIC TEMPERATURE FUSE LINK (L377°, STRAIGHT)
$17.65Ceramic temperature fuse link (straight), opens at 377°F (192°C). 15 Amp. Ceramic body for higher heat environments. Straight terminal orientation.
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STC6257 – CERAMIC TEMPERATURE FUSE LINK (L257°, ELBOW)
$18.69Ceramic temperature fuse link (elbow), opens at 257°F (125°C). 15 Amp. Ceramic body with 90° elbow terminal orientation for tight-fit installations.
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STC6300 – CERAMIC TEMPERATURE FUSE LINK (L300°, ELBOW)
$18.69Ceramic temperature fuse link (elbow), opens at 300°F (149°C). 15 Amp. Ceramic body with 90° elbow terminal orientation for tight-fit installations.
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STC6333 – CERAMIC TEMPERATURE FUSE LINK (L333°, ELBOW)
$18.58Ceramic temperature fuse link (elbow), opens at 333°F (167°C). 15 Amp. Ceramic body with 90° elbow terminal orientation for tight-fit installations.
Signs You May Need a New HVAC Fuse
HVAC systems use fuses to protect the low-voltage control circuit (typically 3A or 5A on the furnace board) and high-voltage disconnect fuses for the outdoor unit.
System Completely Dead — No Response▼
- Nothing happens when the thermostat calls for heating or cooling.
- The control board has no LED lights or diagnostic codes.
- A blown 3A/5A board fuse kills the entire 24V control circuit.
If a board fuse blows repeatedly, there's a short somewhere — usually in the thermostat wiring or a sticking contactor coil. Don't just keep replacing fuses.
Outdoor AC Unit Won't Run▼
- The indoor blower works but the outdoor condenser unit doesn't start.
- Check the disconnect box mounted on the wall next to the outdoor unit.
- Pull-out fuses in the disconnect can blow during power surges or storms.
System Works Intermittently▼
- The system runs sometimes but randomly stops.
- A fuse that's partially blown or has a loose connection can cause intermittent failures.
- Corroded fuse holders in outdoor disconnects are common in humid climates.
Not sure which part you need? Bring your old part to our Dallas store — our team will test it for free and help you find the right replacement.
📞 (214) 340-9421Mon–Fri 10 am – 7 pm | Sat 10 am – 3 pm
📞 (214) 340-9421Mon–Fri 10 am – 7 pm | Sat 10 am – 3 pm