9-115-34-1 – FUSE LINK ASSEMBLY (FIRST CO, N951-1)

A thermal fuse link assembly that opens (blows) at 300°F to protect the system from overheating. This 25 Amp fuse link is a safety device in First Company HX coil units. If it has opened, the system had an overheating event — replace the fuse link and investigate what caused the overheating before restarting.

Specs: 25 Amp, opens at 300°F, ceramic body, stake-on terminals

Replaces: 9-115-34-1, N951-1

Fits: First Company HX coil units

In stock at Open To Public HVAC Parts in Dallas. We test parts at the counter before you buy. Call or text (214) 340-9421.

Specs

• TypeOEM fuse link assembly
• Type BehaviorOne-time use (replace after trip)
• OEM CompatibilityFirst Co

Cross-reference numbers

This part replaces the following OEM and aftermarket numbers:

• FIRST COMPANY
• 9-115-34-1
• N951-1

Not sure if your number matches? Call (214) 340-9421 or bring the old part in — bench-testing is free.

Fits these models

• OEM-specific fuse link assembly — direct factory replacement for First Co / Trane / equipment-specific applications
• Verify exact part number cross-reference to your unit before installing
• Bring the old assembly + unit model number to the counter

What does L333° mean on a temp fuse link?

The L-rating is the trip temperature in Fahrenheit. L333° trips at 333°F. Common ratings: L235°, L257°, L300°, L333°, L377°, L438°, L468°. Match your unit's data plate exactly — these are not interchangeable.

Why does my temp fuse link keep blowing?

On electric heat strips: usually restricted airflow — clogged filter, dirty blower wheel, undersized return, closed-off supplies. The strips overheat without enough air moving across them. On gas furnaces: usually flame impingement from a cracked heat exchanger, misaligned burners, or wrong manifold pressure. Fix the root cause; don't just keep swapping links.

One-time vs resettable — which do I need?

Look at what your existing link is. One-time ceramic / non-ceramic links are SAFETY devices designed to fail permanently — they're catastrophic-failure protection. Resettable breakers are convenience devices for short-cycling. They're NOT interchangeable; match what your equipment was designed for.

Can I bypass the fuse link with a jumper wire?

No. The fuse link is a safety device — bypassing it can cause fires, melted ductwork, CO production from incomplete combustion, or worse. If yours is blown, replace it. Period.

How do I tell if the fuse link is blown?

Use a multimeter on continuity / resistance mode. A healthy link reads near 0 ohms (closed circuit). A blown link reads infinite / OL (open circuit). Visual inspection helps too — blown links often have a visible gap or melted appearance.