ARMT2-HEATER

Supported Applications

The Omega ARMT-2 Series is a rugged clean water immersion heater designed for the direct heating of process fluids in tanks or vessels. The series is specified for use with clean liquids within a pH range of 6 to 8.

A key operational constraint documented by the manufacturer is that the integral thermostat functions as a temperature control only and is not a fail-safe device. An approved pressure or temperature control should be used with these heaters to assure safe operation.

Operating Conditions & Performance

The ARMT-2 Series operates on 1-phase power at voltages of 120, 208, 240, or 490 Vac. Wattage ranges from 1.5 to 15 kW with a watt density between 46 and 53 W/in².

Temperature control is provided by an integral bulb and capillary type thermostat available in two distinct ranges:

• T-2 Temp Range: 60 to 250°F
• T-1 Temp Range: 0 to 100°F

The heater features a copper sheath with a diameter of 0.475" (1 cm) and utilizes a 2 NPT brass fitting screw plug for process connection.

Enclosure Ratings & Approvals

Standard models feature a General Purpose NEMA-1 rated enclosure. An optional type E2 moisture tight/explosion resistant enclosure is available; however, the source notes that the E2 enclosure is not intended for use in hazardous areas.

The series meets specific classification requirements:

• Class I: Groups C & D, Div. 1 & 2
• Class II: Groups E, F, & G, Div. 1 & 2
• Class III: Div. 1 & 2

The series carries SP and UL approvals.

Variants by Wattage and Dimensions

Total weight ranges from 5 to 11 lb (2 to 5 kg) depending on the configuration. The number of heating elements varies between 1 or 2, with overall dimensions changing based on watt density requirements.

• 1.5 kW models utilize a single element and weigh 5 lb (2 kg).
• Models from 2 to 7 kW typically use two elements with weights ranging from 5 to 9 lb (2 to 4 kg).
• Higher wattage configurations of 10, 12, and 15 kW utilize two elements with overall lengths extending up to 54 in (137 cm) for the 15 kW model.

Configuration Options

The series offers configurable options across voltage, temperature range, enclosure type, and wattage. Model numbers follow the format ARMT-<kW>-<voltage>-<thermostat_type>.

Available configurations include:

• Voltages: 120V, 208V, 240V, and 490 Vac (designated in the model number).
• Thermostat Ranges: Standard T-2 range or low-range T-1.
• Enclosure Options: General Purpose NEMA-1 or optional type E2 moisture tight/explosion resistant enclosure (insert 'E2' into the model number).

Wetted Materials and Construction

The wetted materials consist of a copper sheath and brass fitting. The electrical connection is provided via a hole for 3/4 conduit.

Key Product Differences

Variants within the ARMT-2 Series are distinguished by their wattage, voltage rating, thermostat range (T-1 vs T-2), and enclosure type. The model number suffix indicates these specific configurations:

• T-1 Suffix: Indicates the 0 to 100°F temperature control range.
• E2 Insertion: Models with 'E2' inserted into the part number (e.g., ARMT-2255E2T1/240) feature the optional moisture tight/explosion resistant enclosure for an additional cost.

The series does not include a fail-safe mechanism in its integral thermostat; this functional distinction requires external safety controls regardless of the specific variant selected. Additionally, while standard models are NEMA-1 rated, only variants explicitly ordered with the E2 option provide moisture tight/explosion resistant housing characteristics.