Description
The Schneider Electric Harmony RM22-LA / RM4-LA series are specialized liquid level control and monitoring relays, designed to work with conductive (resistive) level electrodes (probes) for automatic pumping control (fill / empty mode) and level alarm functions in tanks, sumps, and wells.
- RM22LA32MR → 2-electrode level controller with pump protection (detects dry-run, overfill; DIN-rail mount, 24V AC/DC or 230V AC coil variants — check suffix).
- RM4LA32B / RM4LA32F / RM4LA32M / RM4LA32MW → Level monitoring relays from the older RM4 family — provide adjustable sensitivity, delay, and mode (pump-up / pump-down / alarm only) with 2 or 3 electrode inputs and optional fault relay.
These units pass a low AC sensing current through the liquid — when probes are bridged by conductive liquid, the relay changes state according to the selected mode (Empty = pump fills until upper probe touched; Fill = pump empties until lower probe uncovered). They include sensitivity adjustment (0.5–100 kΩ typical) to compensate for scaling / water conductivity changes and timed delay to prevent chattering from wave action.
Key Features
- Electrode Inputs: 2 or 3 conductive probes (common REF + HIGH + LOW or ALARM probe).
- Modes: Pump-Down (empty tank), Pump-Up (fill tank), Alarm-Only.
- Sensitivity: Adjustable 0.5–100 kΩ (compensates for probe fouling / low conductivity).
- Time Delay: 0.1–10 s (typical) to reject wave-induced cycling.
- Supply Voltages: 24V AC/DC, 110V AC, 230V AC — confirm exact suffix.
- Output: 1 or 2 changeover contacts (NO/NC) — pump command + alarm.
- Country of Origin: France / Italy (Schneider Global)
Model Reference Table
Model | Series | Function | Electrode Inputs | Typical Supply | Notes |
|---|---|---|---|---|---|
RM22LA32MR | RM22 (Harmony) | Level Controller + Pump Protection | 2–3 probes (REF/L/H or REF/L+Alarm) | 24V AC/DC or 230V AC check suffix | Modern compact DIN version |
RM4LA32B | RM4 (Legacy) | Level Monitor / Controller | 2 probes (REF+L/H selectable) | 230V AC (typical) | Older gen., still widely used |
RM4LA32F | RM4 (Legacy) | Level Monitor — Fill Mode pref. | 2–3 probes | 230V AC | Fill (pump-up) bias |
RM4LA32M | RM4 (Legacy) | Level Monitor — Empty Mode pref. | 2–3 probes | 230V AC | Empty (pump-down) bias |
RM4LA32MW | RM4 (Legacy) | Level Monitor with wider adj. | 2–3 probes | 230V AC (some 24V) | Multi-voltage / wide range |
⚠️ Installation Warnings:
Technical Specifications (Representative — RM22LA32MR)
Parameter | Specification |
|---|---|
Model | RM22LA32MR (Schneider Electric Harmony RM22-LA) |
Function | Conductive liquid level control — Pump-Up / Pump-Down / Alarm |
Number of Electrodes | 2 (REF + Level) or 3 (REF + Low + High) depending on mode |
Sensitivity Range | 0.5 – 100 kΩ (adjustable potentiometer) |
Time Delay | 0.1 – 10 s (adjustable — suppresses wave chatter) |
Supply Voltage | Check suffix: commonly 230V AC 50/60Hz or 24V AC/DC |
Output Relay | 1 or 2 × Changeover (CO / Form C), 5 A @ 250V AC (resistive) |
Pump Protection | Dry-run detection & overfill lockout (on RM22LA32MR) |
Mounting | 35 mm DIN rail (EN 60715) |
Dimensions (W×H×D) | 36 mm (2 TE) × 90 mm × 72 mm (typical for RM22) |
Weight | ~ 0.15 kg |
Standards | IEC 60255, CE, UL, CSA, RoHS |
Warranty & After-Sales
- Factory new units: 12 months warranty
- Refurbished units: 3–6 months warranty
- Technical support for:
- Mode selection (Pump-Up vs Pump-Down wiring & probe placement)
- Sensitivity & delay adjustment for turbulent/foaming liquids
- Probe layout recommendation (reference probe always submerged; Hi/Lo probes at setpoints)
- Cross-reference to obsolete Zelio level relays / older RM4 replacements
- Wiring diagram provided (terminal IDs: A1/A2 = supply; 11-12-14 = output; S1/S2/S3/S4 = electrode commons & probes)
Delivery Time
- Standard delivery: 3–5 working days (stock items)
- Express shipping available upon request
Why Choose Our Store
- Genuine Schneider Electric Harmony control relays
- Global supply network with competitive pricing
- Expertise in pump control panels, sump/borehole level switching & wastewater lift stations
- Comprehensive technical documentation (wiring diagrams, sensitivity curves, probe spacing guide)
- Responsive customer service and support
Applications
- Sump / sewage lift station pump control (pump-down / alternating twin-pump with external interlock)
- Process tank fill control (pump-up — maintain level between Hi/Lo probes)
- High / low level alarm annunciation (separate alarm probe + RM4/RM22 in alarm-only mode)
- Well / cistern level monitoring
- Retrofit of older level switches with modern conductive probe system
Reviews
There are no reviews yet.