KELLER Pressure 23SY-En-H2 Hydrogen ATEX Zone 2 Pressure Transmitter
KELLER’s 23SY-En-H2 is a separate hydrogen-service version of the 23SY pressure transmitter series with increased-safety ATEX equipment category 3G / Ex ec for gas Zone 2. Announced by KELLER on 25 February 2026 together with 23SY-En. It differs from the standard hydrogen 23SY-H2 and from 33X-Ed flameproof Ex db transmitters. Zone 0 and Zone 1 approval must not be inferred.
Documentation and approval restrictions
Exact KELLER 23SY-En-H2 manufacturer model page · Official KELLER Zone 2 launch with both 23SY-En and 23SY-En-H2 · 23SY-En family catalog.
Exact ATEX file/order-code caution: This family announcement substantiates Category 3G Ex ec only. The applicable EU declaration, actual temperature rating, permissible hydrogen process seals, hazardous area marking and electrical connections must be checked on the delivered 23SY-En-H2 part and technical documentation before hazardous-area installation. No IECEx or Ex ia/Ex db certification is claimed from this announcement.
Exact H₂ model specifications: Current KELLER 23SY-En-H2 manufacturer catalog specifies 0–4 to 0–1000 bar pressure ranges, ±0.25% FS accuracy, ±0.7% FS total error band over −10 to +80°C, and 4–20 mA or 0–10 V options. Hydrogen permeation control is supported by a gold-plated diaphragm and hydrogen-compatible alloy selection.
23SY-En-H2 — hydrogen and Zone 2 evidence
The 23SY-En-H2 combines a hydrogen-compatible pressure-measuring construction with the manufacturer’s increased-safety Ex ec family positioning for gas Zone 2. It is a different order family from standard 23SY-H2 and from 33X-Ed flameproof protection. For a hydrogen application, compare actual wetted diaphragm/alloy, calibrated pressure span, temperature, enclosure and cable accessories with the supplied certificate. Do not infer Zones 0/1 or an IECEx approval from an ATEX-marked Zone 2 instrument unless independently documented.