ERECTA SWITCH® by Compac Engineering

Series 20 — Extended Stem Hardware

Series 20 Extended Stem Hardware provides the mechanical and electrical infrastructure for mounting liquid level switches at extended stem lengths. The system includes control heads with factory-sealed relay compartments, relay housing bodies, stem sets, and associated hardware. Control heads accept 20-726 stem sets fastened with set screws; all stem/head interfaces are O-ring sealed for rain-tight service. Available in 120V and 240V configurations.

20-725 — Control Heads

The 20-725 control head houses a factory-sealed relay compartment with a 20A SPDT relay. O-ring sealed rain-tight construction with removable cap. Accepts 20-726 stem sets. Includes 20-903 connector set. Injection-molded fire-retardant ABS housing rated to 130°C.

20-725-120 Control Head 120V

20-725-120

Control Head · 120V · 3/4 HP · 20A SPDT

As low as $95.47

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20-725-240 Control Head 240V

20-725-240

Control Head · 240V · 1-1/2 HP · 20A SPDT

As low as $95.47

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20-725 Control Head — Catalog Drawing Page 410A
Page 410A — 20-725 Control Head · O-Ring Sealed Rain Tight Construction

20-725-HS — Relay Housing, O-Ring Seal + Set Screws

The 20-725-HS is the housing body for use when building or replacing the enclosure in a Series 20 extended stem installation. Features removable cap with O-ring seals at cap and base for rain-tight service. Accepts 20-726 stem sets fastened with four set screws; stem/head interface is O-ring sealed.

20-725-HS Relay Housing

20-725-HS

1-1/4 Relay Housing · O-Ring Seal · Set Screws

As low as $27.69

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20-725-HS 1-1/4 Relay Hsg O-Ring Seal + Set Screws — Catalog Drawing Page 411A
Page 411A — 20-725-HS 1-1/4 Relay Hsg O-Ring Seal + Set Screws · RoHS Compliant

System Overview

The Series 20 extended stem system is designed for applications requiring the liquid level sensing element to be positioned at a distance from the control head. Key system features:

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Frequently Asked Questions

Common Questions About This Product

What is the difference between a float level switch and a liquid level sensor?

A float level switch like the Series 20 level switch is a point-level device: a float rides the liquid and actuates a magnetic reed switch at a set height, giving a simple on/off signal — no power, no firmware, no calibration. "Sensors" usually means continuous measurement (ultrasonic, radar, capacitive). ERECTA SWITCH targets reliable discrete-point control.

What factors should I consider when choosing the Series 20 level switch?

Consider media chemistry (pick PP, AC, or KR), liquid specific gravity, operating temperature and pressure, mounting style, number of switch points, and electrical contact rating. Compac will spec it from your application — request a free evaluation sample.

What liquid chemistries is the Series 20 level switch compatible with?

Choose the material to match the media: Polypropylene (PP) for general aqueous, acids, and bases; Acetal (AC/Delrin) for solvents, fuels, and hydrocarbons; Kynar PVDF (KR) for aggressive or harsh chemicals. Most ERECTA SWITCH models are offered in all three materials; some are material-specific, so check the product page for the model you need.

What mounting options are available for the Series 20 level switch?

ERECTA SWITCH offers vertical top-mount, bulkhead, and extended-stem configurations, plus side-mounted single-point models. The mount style is part of the model number — select the configuration that matches your tank geometry.

How is the actuation level set on the Series 20 level switch, and how accurate is it?

Point detection is repeatable and mechanical. The trip height on the Series 20 level switch is set by the 10-715 Precision Nipple, ordered separately in 1-inch increments (1″–70″), so you place the switch point exactly where the application needs it.

What pressure and temperature can the Series 20 level switch handle?

It depends on the series, and the derate matters more than the headline. Series 10 is rated 100 PSI, Series 15 50 PSI and Series 20 20 PSI — each at 20°C, each derating to zero at 90°C, so a hot line has no pressure allowance left. Series 20 sits lowest by design: its float sections are thin-walled, and sustained pressure can crush them. Temperature follows the material — on Series 10, PP: 180°F, AC: 200°F, KR: 280°F.

Can one Series 20 level switch switch control both a high and a low level?

A single switch detects one point. For high-plus-low detection (or more), use a multi-level extended-stem set that places multiple reed points on one stem, giving you independent high and low signals from a single mounting hole.

How do I wire the Series 20 level switch to a pump or alarm?

The Series 20 level switch uses a magnetic reed switch wired in series with your relay or controller. Contact rating is 70 VA / 50 W resistive (UL File E70063). The switch ships with lead wires — connect directly to your control circuit.

Does the Series 20 level switch need calibration?

No. The Series 20 level switch is a mechanical float actuating a sealed reed switch — there is nothing to calibrate or power. This is a reliability advantage over electronic sensors that can drift over time.

How do I maintain the Series 20 level switch, and what if it stops working?

Inspect that the float moves freely (check for debris or scaling), then test reed continuity with a multimeter. Because ERECTA SWITCH is modular, you replace only the individual component — switch, float, connector, or fitting — instead of the whole assembly.

Is the Series 20 level switch safe for flammable or hazardous-area liquids?

Standard ERECTA SWITCH models are not rated for hazardous (Class I / Div) areas. For flammable-service applications, contact Compac engineering to discuss your requirements and available options.

What are the typical applications for the Series 20 level switch?

The Series 20 level switch is used for pump start/stop control, high-level overflow protection, low-level dry-run protection, and tank or reservoir level alarms in OEM equipment. The modular ERECTA SWITCH system is built into laundry, HVAC, water-treatment, hydraulic, and chemical-handling machinery.

What makes ERECTA SWITCH different from other switches?

It is the only fully modular, off-the-shelf liquid level switch system: switch, float, connector, fitting, and nipple are independently field-replaceable and stocked. OEMs configure exactly what they need with no minimums and short lead times. Made in Paradise, California; RoHS compliant.