Case Study: Protecting Firepump Solenoids with TM301 Timer
Industry: Firepump Systems
Product Used: Bolec TM301 Timer Module
Application: Auto Stop Signal Cut‑Off
The TM301 Timer: Compact, Reliable, Firepump-Safe
Background
Firepump systems rely on precision timing. In this case, a solenoid was used to shut off the engine when the STOP button was pressed — but the solenoid couldn’t withstand prolonged energization. Users were unintentionally causing coil burnout by holding the button too long.
The onboard delay circuit had failed, so a safer external control was needed.
The Challenge
- STOP button held too long → solenoid overheats
- Solenoid not designed for continuous power
- Internal delay circuit broken
- Needed: fail-safe delay-off solution
The Solution: TM301 Timer
Using the Bolec TM301, the system now energizes the solenoid for 4.5 seconds only, then automatically cuts power — no matter how long the STOP button is pressed.
DIP Switch Settings:
| Switch | Setting | Function |
|---|---|---|
| 1 | ON | Instant ON, Delay OFF |
| 2 | OFF | One-shot mode |
| 3 | OFF | Seconds range |
| 4 | OFF | 1–30 second scale |
| 5 | ON (12V) or OFF (24V) | Voltage match |
Wiring Highlights:
- STOP button triggers TM301 input
- Relay output via Normally Open contact
- After 4.5s → timer cuts power to solenoid
- Reverse EMF diode recommended
Outcome
- Solenoid protected from user error
- Timing now consistent and safe
- No more reliance on failed internal circuits
- Cost-effective fix using a compact timer
Where Else TM301 Shines
- Diesel glow plug preheat
- Turbo cool-down timers
- Alarm-before-shutdown systems
- Start/stop engine panels
Let’s Fix Yours Too
If you’re facing a similar problem or want a robust timer for critical systems, contact our team today.