What It Is

The YEJ series is a mechanical pressure gauge designed for low‑pressure and negative‑pressure (vacuum) measurement of neutral, non‑corrosive gases. It uses a sensitive capsule element – not a common Bourdon tube – so it can measure down to just a few hundred pascals.

The rectangular case fits neatly into control cabinets or tight panels.

Two Models – Pick What You Need

YEJ‑101 (Indicator only)

• Pure mechanical indication – no electricity required

• Easy to read, always works even during a power outage

• Best for on‑site monitoring of boiler air supply, flue gas ducts, or ventilation systems

YEJ‑121 (With electric contacts)

• Adds preset upper and lower limit contacts

• Can directly trigger alarms, relays, or PLC inputs

• Great for automatic pressure control or safety interlocking

Key Features (No Jargon)

• Sensitive to very low pressure – Works perfectly where ordinary gauges show no movement

• Low air intake – Does not disturb the system being measured

• Rectangular housing – Space‑saving, stable, and vibration‑resistant

• YEJ‑121 contact capacity – 3A 220V AC, enough for most alarms and small relays

• Wide pressure range options – From –250 Pa up to 60,000 Pa (positive, vacuum, or compound)

Typical Applications

• Boiler combustion air monitoring

• Flue gas duct pressure (draft measurement)

• Cleanroom differential pressure

• HVAC air filters and duct static pressure

• Dust collection systems

• Laboratory test benches for low‑pressure gases

Simple Specs (No Table)

• Accuracy: 2.5% of full scale

• Pressure connection: φ8 tube (fits φ6 inner diameter hose)

• Operating temperature: –20°C to +60°C

• Humidity: ≤85% RH

• Weight: YEJ‑101 ~2 kg ; YEJ‑121 ~2.5 kg

• Power (YEJ‑121 only): AC 220V, <5W

Why Choose YEJ?

• No external power for YEJ‑101 – truly independent mechanical gauge

• Easy to mount – rectangular shape fits flat panels

• Reliable in vibration – less pointer drift than round gauges with the same mechanism

• Contact version saves cost – no need for a separate pressure switch

YUN YI ,we are professional manufacturer that engaged in the fields of pressure measurement instrument.
we have 12 years sensor producing and developing experiences

Xi'an Yunyi Instrument Co., Ltd is a professional R&D center and manufacture of measuring instruments.And here's a variety of products for you choice: pressure transmitters,temperature transmitters,flow transmitters,weighing instruments and so on.Our products have been made by advanced technology, with high quality, fast delivery period, which have attracted so many domestic and foreign customers.

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