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Brand: Chromalox
Chromalox ARTM / ARMT Clean Water Screw Plug Heaters
Description
Clean water screw plug heaters with a built-in thermostat
The Chromalox ARTM / ARMT family is a range of brass screw plug immersion heaters with copper sheath elements for heating clean water. Unlike the plain MT range, each heater carries an integral thermostat and a thermowell, so a tank can be held at a set temperature without a separate controller. The plug threads into a boss in the tank wall and the elements heat the liquid directly.
Four series cover plug sizes from 1 in to 2-1/2 in NPT. The small ARTM and ARMT-1 heaters are single-phase 120 and 240 V units from 0.75 to 3 kW, while the ARMT-2 series reaches 15 kW at 120 to 480 V single phase.
Technical specifications
| Parameter | Specification |
|---|---|
| Series | ARTM, ARMT-1, ARMT-2 and ARMT-3 clean water screw plug immersion heaters with integral thermostat |
| Plug | Brass NPT screw plug: 1 in (ARTM), 1-1/4 in (ARMT-1), 2 in (ARMT-2) and 2-1/2 in (ARMT-3) |
| Element sheath | Copper sheath elements, 0.315 in or 0.475 in diameter depending on series |
| Thermostat | Integral thermostat: SPST on ARTM and ARMT-1, DPST on ARMT-2 and ARMT-3 |
| Temperature ranges | T4 60 to 187 deg F, T5 60 to 240 deg F, T8 0 to 127 deg F (ARTM, ARMT-1); T2 60 to 250 deg F and T1 0 to 100 deg F (ARMT-2) |
| Supply | 120 and 240 V single phase on ARTM and ARMT-1; 120, 208, 240 and 480 V single phase on ARMT-2 |
| Terminal enclosures | E1 general purpose (UL Listed, CSA Certified); E2 moisture / explosion resistant (CCSAUS Certified) on ARTM and ARMT-1 |
| Example ARTM-1000T4 | 1 kW, 85 W/in2, 120 V PCN 191273 or 240 V PCN 191281; dimension B 6-5/16 in |
| How to order | Specify model, volts, phase, kW, PCN and quantity |
Series overview
| Series | Plug | Rating | Thermostat | W/in2 |
|---|---|---|---|---|
| ARTM | 1 in NPT | 0.75 – 3 kW | SPST | 64 – 86 |
| ARMT-1 | 1-1/4 in NPT | 1 – 2 kW | SPST | 43 – 86 |
| ARMT-2 | 2 in NPT | 1.5 – 15 kW | DPST | 46 – 53 |
| ARMT-3 | 2-1/2 in NPT | see sheet | DPST | 46 – 53 |
The ARTM list runs from ARTM-750 to ARTM-3000 with element length dimension B growing from 6-5/16 in to 19-7/8 in. Each model is listed with a T4, T5 or T8 thermostat range suffix, and E2 appears in the model code for the moisture resistant enclosure, as in ARTM-1000E2T4. The ARMT-1 models are ARMT-110-3, ARMT-112, ARMT-115 and ARMT-120 on two elements.
Choosing a thermostat range and enclosure
Pick the T4 range for general warm water up to 187 deg F, T5 where up to 240 deg F is needed, and T8 for cold-side control from 0 to 127 deg F. On the ARMT-2 series the T2 and T1 suffixes give 60 to 250 deg F and 0 to 100 deg F. Choose the E1 enclosure for general purpose areas and E2 where a moisture resistant or explosion resistant housing is required. Stock status in the sheet is shown as S for stock and NS for non-stock, so confirm availability at quotation.
The sheet marks these heaters for non-potable service only, so do not specify them for drinking, food preparation or washing water. Check the boss thread, immersion depth, voltage and phase before ordering. Related heating equipment is listed under HVAC and combustion, and the plain copper range without a thermostat is on the
page.Documents and quotation
The Chromalox ARTM/ARMT clean water catalog sheet with every model and part number is attached. Seven Star LLC, an independent supplier in Muscat, quotes from the model, voltage, phase and kW; stock and lead time are confirmed at quotation.
Datasheets & Documents
- Datasheet Chromalox ARTM / ARMT Clean Water screw plug heaters catalog sheet (English) Download
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About brand
Chromalox is an American manufacturer of industrial electric heating and heat tracing. It traces its start to a 1915 patent by Pittsburgh engineer Edwin L. Wiegand for a resistance wire sealed in insulating refractory inside a metal sheath, the basis of the modern sheathed heating element. The company was incorporated in 1917 and has been part of the Spirax Group since 2017.
Seven Star LLC is an independent supplier in Muscat. We list selected Chromalox heaters, heat trace and controls for process and utility projects in Oman and the GCC.
Chromalox company profile
| Founded | 1917, Pittsburgh, Pennsylvania, USA, by Edwin L. Wiegand |
|---|---|
| Origin | Wiegand's 1915 patent for a sheathed resistance heating element |
| First order | A strip heater for what became the electric household clothes iron |
| Ownership | Spirax Group (formerly Spirax-Sarco Engineering) since 2017 |
| Product families | Immersion, circulation and flanged heaters, tubular, strip and cartridge heaters, explosion-proof heaters for hazardous areas, self-regulating and constant-wattage heat trace cable, temperature controllers and control panels |
Milestones
- 1915: Edwin L. Wiegand patents the sheathed heating element.
- 1917: The company is incorporated.
- 2011: Sentinel Capital Partners acquires Chromalox.
- 2017: Spirax-Sarco Engineering acquires Chromalox.
Chromalox product series
Immersion heaters include the MT and EMT screw plug heaters and the ARTM and ARMT heaters for clean water, the MTS and EMTS stainless screw plug heaters and the STFX small tank flange heater from 1 to 25 kW.
Heat trace products include the SRL self-regulating cable, the CWM constant wattage cable, the DTS-HAZ heat trace thermostat for hazardous areas and the ITC1 and ITC2 digital heat trace controllers. Controls include the 6140 and 4140 temperature and process controllers and the C4 four-zone SCR power controller.
Where Chromalox products are used
Heating water, oil and process fluids in tanks and vessels, freeze protection and temperature maintenance of pipes, and temperature and power control of heaters in industrial plants.
Chromalox products we list
Ordering Chromalox products: what we need
Send the full model code, voltage and phases, kW or wattage, sheath material, immersion length and connection size for heaters, and for heat trace the pipe size, length, maintain temperature and hazardous-area classification. We prepare quotations from the Chromalox data sheet.
Facts checked against published Chromalox company histories, October 2026.
Browse Chromalox products by category: Process Heaters & Heat Tracing, Controllers & Data Acquisition, Temperature Instrumentation, Contactors & Overload Relays.
FAQ
Questions about the Chromalox ARTM / ARMT Clean Water Screw Plug Heaters
Answers from our engineering team on installation, compatibility and integration.
01Do ARTM and ARMT heaters include a thermostat?
Yes. Each has an integral thermostat, SPST on the ARTM and ARMT-1 series and DPST on the ARMT-2 and ARMT-3 series, plus a thermowell.
02What plug sizes are available?
The series use 1 in (ARTM), 1-1/4 in (ARMT-1), 2 in (ARMT-2) and 2-1/2 in (ARMT-3) NPT brass screw plugs.
03What kW range do the smaller series cover?
The ARTM covers 0.75 to 3 kW and the ARMT-1 covers 1 to 2 kW, both at 120 or 240 V single phase.
04Which thermostat ranges are offered on ARTM?
T4 is 60 to 187 deg F, T5 is 60 to 240 deg F and T8 is 0 to 127 deg F, selected by a suffix on the model.
05Can these heaters be used for drinking water?
No. The sheet states they are for non-potable service only, so they are not for drinking, food preparation or washing water.
Reviews
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