ARMTO2-MEDIUM

Supported Applications

The Omega ARMTO-2 Series is a medium weight oil immersion heater with an integral thermostat, designed for heating applications involving specific viscous fluids. The series identity centers on low watt density operation suitable for:

• Medium viscosity oils
• Industrial gear oils
• Numbers 4 and 5 residual fuel oils

The integral thermostat functions as a temperature control only. The documentation notes that this is not a fail-safe device; an approved pressure and/or temperature limit control should be used with these heaters to assure safe operation.

Operating Conditions & Performance

The ARMTO-2 Series operates on 1-phase power at 208, 240, or 480V. The heater elements are configured for a watt density of 15 W/in² across the series envelope. Power ratings range from 2 to 6 kW depending on the selected model and enclosure type.

Temperature control is provided via an integral thermostat with three distinct ranges:

• T1: 0 to 100°F
• T2: 60 to 250°F
• T3: 200 to 550°F

The heater features a steel sheath with a diameter of 0.475 in and connects via a 2 NPT Steel Fitting.

Approvals & Certifications

• General Purpose Enclosures: UL Listed (with T1 or T2 temps) and CSA certified (with T1, T2, or T3 temps).
• E2 Moisture Resistant/Explosion Resistant Enclosures: CSA NRTL/C certified with T1, T2, or T3 temps.

The E2 construction refers to heater design features providing explosion-resistant containment of electrical wiring according to the National Electric Code. The documentation cautions that abnormal application or use at excessive temperatures can create hazardous conditions leading to fire; consult Omega for data on allowable watt densities for more viscous materials.

Dimensions & Weight

Overall dimensions vary by power rating and enclosure type:

• E1 (General Purpose): Overall length ranges from 16.7 cm (24¼ in) for the 2 kW model to 41 cm (67¼ in) for the 6 kW model.
• E2 (Moisture Resistant/Explosion Resistant): Overall length ranges from 16 cm (24¼ in) for the 0.2 kW model to 31 cm (57¼ or 67¼ in depending on configuration).
• Hole Size: Minimum of 5.7 cm (2.25 in).

Total heater weight ranges from 4 lb (8 kg) to 8 lb (17 kg), with E2 enclosures generally weighing more than general purpose equivalents at the same power rating.

Electrical Connections

• Housing: Screw Plug: 2 NPT steel.
• Conduit Hubs: Two (1.5) NPT conduit hubs, with one side plugged.

Configuration Options

The series supports a configurable envelope defined by power output, temperature range, enclosure type, and voltage designation. The model number format follows the pattern: ARMTO-<kW>-<voltage>-<temp_range>-<enclosure_type>.

• Power (kW): Available in 2, 2.66, 3.33, 4, 5, and 6 kW steps.
• Voltage: Designated as part of the model number; options include 208V, 240V, or 480V (1-phase).
• Temperature Ranges: Configurable via T1, T2, or T3 suffixes.
• Enclosure Types:

The series offers two primary enclosure configurations:

• General Purpose (NEMA-1 rated): Standard steel housing for indoor use.
• E2 Moisture Resistant/Explosion Resistant: Enhanced construction for environments requiring moisture resistance or explosion-resistant containment of electrical wiring.

Note: The 0.2 kW option is listed only in the E2 enclosure table, while other power levels are available across both enclosure types depending on the specific model configuration.

Wetted Materials & Construction

• Sheath: Steel (0.475" diameter).
• Fitting: 2 NPT Steel Fitting.

The series utilizes two heating elements per unit across all power ratings listed in the specification tables.

Key Product Differences

Variants within the ARMTO-2 Series are distinguished by their enclosure rating, temperature range setting, and electrical input voltage. The model number explicitly indicates these distinctions:

• Enclosure Designation: Models with "E2" in the part number (e.g., ARMTO-2026E2T1/480V) feature moisture resistant/explosion resistant enclosures. Models without this designation utilize general purpose NEMA-1 rated housings.
• Temperature Range: Suffixes T1, T2, or T3 denote the thermostat range (0 to 100°F, 60 to 250°F, and 200 to 550°F respectively). Some general purpose models omit the suffix when configured for a default range in specific contexts, but explicit model numbers include these identifiers.
• Voltage: The final segment of the part number specifies the voltage (e.g., /240V or /480V).

The physical dimensions and weight differ between E1 (general purpose) and E2 enclosures for equivalent power ratings, with E2 units typically having greater overall length and mass.