Description
The Omron 61F-G3 is an Electrode (Conductivity) Type Level Controller / Relay Unit from the classic 61F Series, designed to detect liquid levels (conductive liquids only — water, aqueous solutions) by measuring conductivity between a common electrode and high/low probe electrodes. The suffix “G3” typically denotes the Relay Main Unit (with or without built-in pump control logic depending on sub-suffix — G3 = 3-wire control: common(COM), high(H), low(L) electrodes; some G versions are for float-less / electrode control with pump alternating function).
- 61F-G3 → AC-powered (100–240V AC or 24V AC/DC depending on exact sub-code — standard 61F-G3 = 100–240V AC 50/60Hz input) — provides SPDT relay output (1 c/o — NO/NC) for alarm or pump control, and often a second SPDT for pump alternation / high-high alarm on -G4 versions; the G3 is the 3-electrode (Common + High + Low) single-pump / single-alarm version.Clarification:Omron 61F series naming: 61F-GP-N / 61F-GP-AC110/220 = standalone electrode controller with built-in relay; 61F-G3 often references the *relay base unit used with 61F-11N/-12N expansion or the GP version — in modern catalog 61F-G3 ≈ 61F-GP-N (General Purpose electrode controller, 3-electrode, 1 pump relay + 1 alarm relay on some -G3N versions — check your exact 20-char). The “Float Less” in your query = “Floatless Level Switch” — Omron’s term for conductivity-based level detection (no moving float).
- The 61F-G3 works with electrode rods (61F-EC□□ / 61F-EZ□□ — sold separately) screwed into tank — connected via terminal block on 61F-G3: E (Common / Earth electrode immersed always), H (High-level electrode — when covered → pump OFF / alarm), L (Low-level electrode — when uncovered → pump ON / alarm). Sensitivity adjustable (5–50 kΩ typical) to accommodate different water purity (pure water = high resistance → may need lower sensitivity / different electrode spacing).
- Typical use: Sump pump control (auto ON at Low probe / OFF at High probe), tank overfill / dry-run alarm, boiler drum level monitoring (conductive media only — NOT for oil / hydrocarbon / deionized water unless special low-sensitivity setting).
Key Features
- Level Detection Method: Conductivity (Floatless — no moving parts / floats)
- Electrode Inputs: 3-wire (Common E + High H + Low L — also test T terminal on some)
- Control Output: 1 × SPDT relay (pump/valve control — rated 5A 250V AC resistive) + often 1 × SPDT alarm relay (on -G3N / GP-N — check sub-suffix)
- Sensitivity Adjustment: 5–50 kΩ (turn potentiometer — set to ~2× the liquid resistance between E & H probes)
- Power Supply: 100–240 V AC (50/60 Hz — typical for 61F-G3; 24V AC/DC version = 61F-G3-D or 61F-GP-D)
- Country of Origin: Japan (Omron Corporation)
Model & Variant Reference (Omron 61F Floatless / Electrode Level Controllers)
Model | Power / Type | Electrode Inputs | Output | Notes |
|---|---|---|---|---|
61F-G3 (listed) | 100–240V AC — Relay Unit (GP type) | 3 (E/H/L) + Test T | 1 SPDT pump + 1 SPDT alarm (on G3N/GP-N — verify suffix) | Classic “Floatless” conductivity controller — needs electrode rods (61F-EC8 / EZ8 etc.) |
61F-G4 | 100–240V AC | 3 + Alternating Pump Ctrl | 2 × SPDT (pump A/B alternate) + alarm | Dual-pump alternating — lead-lag change each cycle |
61F-GP-N / 61F-GP-AC110/220 | Same as modern G3 — renamed GP series | 3 (E/H/L) | 1 × SPDT (5A) + 1 × SPDT alarm (some) | Modern equivalent — G3 often cross-ref to 61F-GP-N |
61F-11N / 61F-12N | Expansion Relay Units (for multi-point alarm) | N/A (driven by 61F-G3) | Adds extra alarm relays | Used with G3 base for extra high/low alarms |
61F-EC8 / 61F-EZ8 | Electrode Rod (8″ / 200mm titanium/SS) | — | — | Sold separately — screws into tank, wires to 61F-G3 E/H/L terminals |
⚠️ Critical Notes:
Technical Specifications (61F-G3 — Electrode (Floatless) Level Controller, 100–240V AC, 3-Probe + Test)
Parameter | Specification |
|---|---|
Model / Order Code | 61F-G3 (Omron 61F Series Floatless Level Controller — Electrode Type) |
Series | 61F (classic conductivity level control — “Floatless”) |
Power Supply | 100–240 V AC (50/60 Hz) — some -D suffix = 24V AC/DC — verify full code |
Electrode Inputs | 3 + Test: E (Common — always immersed), H (High level), L (Low level), T (Test — momentarily shorts E-H to simulate high) |
Sensitivity (Conductivity Setpoint) | Adjustable 5–50 kΩ (potentiometer on front — set < liquid resistance between E↔H/L) |
Control Output — Pump/Main | 1 × SPDT relay — 5 A 250 V AC resistive (NO/NC configurable — pump start/stop) |
Alarm Output (on G3N / GP-N) | 1 × SPDT relay — 5 A 250 V AC (high-high / dry-run / electrode fault — check suffix) |
Pump Delay / Hysteresis | Typically 0–10 s adjustable (some versions fixed ~2 s) — prevents chatter near level |
Indicators (LED) | PWR (green — supply OK), PUMP (yellow — pump relay energized), ALM (red — alarm if fitted) |
Back-panel / Terminals | Screw terminals (M3.5 — accept AWG 24–14 / 0.2–2.5 mm²) for AC supply, E/H/L/T, relay contacts |
Operating Temp. | -10 … +55 °C (no freezing/dewing) |
Dimensions (W×H×D) | ~ 45 mm(W) × 90 mm(H) × 100 mm(D) — DIN rail mount (35 mm top hat) or surface |
Weight | ~ 0.25 kg |
Standards | CE, UL, cUL, KC, RoHS (newer lots) |
Required Accessories (sold sep.) | Electrode rods (61F-EC8 / EZ8 / custom length), electrode holder / tank bushing (61F-HP□), wiring to tank |
Country of Origin | Japan (Omron Corporation) |
Warranty & After-Sales
- Factory new units: 12 months warranty
- Refurbished units: 3-6 months warranty (power-up + simulate probe wet/dry via test terminal → verify relay pick/drop)
- Technical support for:
- Electrode selection (61F-EC8 = 8″ Ti rod; EZ8 = 8″ SS rod — for mild/aggressive media; custom length avail 61F-EC□□ / EZ□□ up to 1m+)
- Sensitivity setting walkthrough (measure R between E↔H in liquid → set pot slightly below that Ω value — e.g., liquid R=15kΩ → set ~10kΩ)
- Pump logic wiring (sump: L=low probe → pump ON; H=high → pump OFF — wire pump contactor coil to NO/Common of pump relay; add overload in series)
- Alarm usage (dry-run / overfill — if G3 has alarm relay, wire to announce probe failure or high-high)
- Cross-ref to 61F-GP-N (modern GP series = functional equivalent to G3 in most apps)
- Tank bushing / electrode holder (61F-HP3 / HP4 — Rp 1/2″ / 3/4″ PT or PF)
- Optional: Electrode rods (61F-EC8 / EZ8 / EC15 / EZ15), holder (61F-HP3 / HP4), expansion alarm unit (61F-11N), 24V DC PSU if using DC version
Delivery Time
- Standard delivery: 3-5 working days (stock NOS)
- Express shipping available upon request
Why Choose Our Store
- Genuine Omron 61F series — not aftermarket (sensitivity pot & relay contact rating critical for long life)
- Global supply network with competitive pricing on legacy Omron level controls
- Expertise in Omron 61F electrode level system (probe selection, sensitivity adj., pump logic wiring, cross to GP series)
- Comprehensive technical documentation (61F-G3 terminal layout, electrode wiring diagram E/H/L, sensitivity set procedure, pump hookup sketch)
- Responsive customer service and support
Applications
- Sump / Sewage Pump Control: Auto ON at Low probe / OFF at High probe — 61F-G3 + electrode rods in pit.
- Tank Overfill / Dry-Run Protection: High-level alarm (H probe covered → alarm relay) + Low-level (L uncovered → dry-run warn).
- Boiler / Process Vessel (Conductive Media): Monitor conductive liquid level — stainless steel or Ti electrodes resist corrosion.
- Retrofit Float Switches: Replace mechanical float (prone to stick/scale) with 61F electrodes — no moving parts.
- Wastewater / Cooling Tower Basin: Reliable even with mildly dirty water (periodically clean electrodes of scale).
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