ERECTA SWITCH® by Compac Engineering
Series 5 · ERECTA SWITCH®

5-18-AC — Flow/No-Flow Indicator — Acetal

Visual-only flow indicator. No electrical output. Transparent polysulfone window shows poppet position to confirm flow presence. Acetal construction handles solvent, hydrocarbon, and chemically aggressive applications beyond polypropylene's range.

5-18-AC Flow/No-Flow Indicator — Acetal

Configure & Order

Material
AC — Acetal
SKU: 5-18-AC
Qty
Requires accessory fittings — 9/16-18 UNF ports need Series 5 fittings for pipe connection. View 5-XX Fittings →
In stock · Ships Wednesday · Made in Paradise, CA · No minimum order
Net Price — per unit
QuantityPrice
1–9$31.89
10–24$29.08
25–49$25.06
50–99$22.66
100–199$19.65
200+$16.24
As low as $16.24 · OEM pricing for 1000+ quoted upon request.

Product Description

The 5-18-AC is the visual flow indicator in acetal for petroleum and hydrocarbon service.

SpecificationValue
Series5-18
TypeVisual indicator only — no electrical output
MechanismSpring-loaded poppet (same as 5-20/5-21)
BodyAngle body
Overall Length4.6 in (116.8 mm)
Ports3× 9/16-18 UNF
MaterialsAcetal
ComplianceRoHS

What Makes the 5-18-AC the Right Choice

Visual flow confirmation — no wiring
Transparent polysulfone window shows poppet position. No electrical connection, no wiring, no switch. Ideal as a secondary confirmation device.
Same poppet mechanism as 5-20/5-21
Spring-loaded poppet in an angle body. Interchangeable poppets with the rest of the Series 5 line.
ERECTA SWITCH modular architecture
Every component is independently field-replaceable. Poppets, fittings, and trim sets service individually — no need to replace the entire switch body.
Acetal construction
Handles solvent, hydrocarbon, and chemically aggressive applications beyond polypropylene. Acetal resists fuels, hydraulic fluids, and many organic solvents.
Hermetically sealed reed switch
SPST N.O., closes on flow. 70 VA / 50W resistive. 0.5A AC / 0.7A DC. 300 VAC / 350 VDC maximum. No mechanical contact with liquid.
RoHS compliant · Made in USA
Every Series 5 switch manufactured in Paradise, California. RoHS compliant throughout. No minimum order.

Where the 5-18-AC Is Specified

Frequently Asked Questions

Common Questions About This Product

What are the typical applications for the 5-18-AC?

The 5-18-AC 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 liquid chemistries is the 5-18-AC 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. Every ERECTA SWITCH model is offered in all three materials.

How do I wire the 5-18-AC to a pump or alarm?

The 5-18-AC 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 5-18-AC need calibration?

No. The 5-18-AC 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 5-18-AC, 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.

What pressure and temperature can the 5-18-AC handle?

Series 10 level switches are rated to 100 PSI; Series 5 flow switches to 200 PSI. Operating temperature depends on the housing material — Polypropylene, Acetal, and Kynar PVDF each have different thermal limits. Contact Compac engineering for your specific conditions.

Questions About This Product?

Our engineering team can verify compatibility with your application and chemistry before you order.