The Manual/Auto/Off rocker or button is the source of 50% of user support queries. Here is how it works according to the official manual specifications:
If you’ve lost control of the settings, perform a hard reset:
The Sinotimer MC101 has screw terminals on the top and bottom. WARNING: Always disconnect mains power before wiring. sinotimer mc101 manual
Standard 230V AC Wiring:
Most MC101 models switch only the Live wire. The Neutral is usually passed through directly to the load. The Manual/Auto/Off rocker or button is the source
Common Wiring Mistake: Users often connect Neutral to Terminal 1 and Live to Terminal 2. While it may work, it is unsafe and violates the manual. Always match polarity as labeled.
In critical timing applications—like HVAC system staging, water treatment chemical dosing, or lighting control in tunnels—a misconfigured MC101 can cause costly downtime or unsafe conditions. The manual is the only authoritative source for reset behavior: Does the timer reset on power loss? (Answer: yes, but cumulative modes maintain count with backup capacitor, clearly noted in the fine print). How short can the trigger pulse be? (20ms minimum, per the specs). Without the manual, trial-and-error can destroy the relay or worse, the downstream equipment. Most MC101 models switch only the Live wire
The manual also clarifies the MC101’s unique selling points: its ultra-wide operating voltage (eliminating the need for separate 12V and 240V stock-keeping units) and its true isolated relay output (2A at 240V AC resistive – moderate but adequate for signal and small contactor duties). These details are not obvious from the product label.