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Brand: Chromalox
Chromalox MTS / EMTS Stainless Screw Plug Immersion Heaters
Description
Stainless steel screw plug heaters for process water and mild solutions
The Chromalox MTS / EMTS heaters use passivated stainless steel for both the NPT plug and the hairpin elements, which makes them the stainless alternative to the copper MT series. They screw into a threaded tank boss and heat process water and corrosive solutions by direct immersion, with a terminal enclosure on the plug and a thermowell for the control sensor. They are supplied without a thermostat.
Ratings run from 0.75 kW in the 1 in plug up to 18 kW in the 2-1/2 in plug, and three-phase builds exist from the EMTS-3 upwards. Lower watt densities of 23 and 15 W/in2 are also listed for 2 in plugs where the solution is more demanding on the sheath.
Technical specifications
| Parameter | Specification |
|---|---|
| Series | MTS / EMTS process water and corrosive solution screw plug heaters |
| Wetted materials | Passivated stainless steel NPT screw plug and passivated stainless steel hairpin elements |
| Thermostat | Not included; thermowell provided for the control sensor |
| Plug sizes | 1 in, 1-1/4 in, 2 in and 2-1/2 in NPT, depending on series |
| Watt density | High (43 to 86 W/in2) on the smaller series, 38 to 53 W/in2 on the larger series, plus medium (23 W/in2) and low (15 W/in2) density 2 in NPT builds |
| Terminal enclosures | E1 general purpose (UL Listed, CSA Certified); E2 moisture / explosion resistant (CCSAUS Certified); E4TP moisture resistant |
| Example MTS-750 | 0.75 kW, 64 W/in2, 120 V PCN 037049 or 240 V PCN 037057; MTS-750E2 PCN 037188 and 037196; MTS-750E4TP PCN 060230 and 060249 |
| How to order | Specify model, volts, phase, kW, PCN and quantity, adding E2 or E4TP to the model for those enclosures |
Series overview
| Series | Plug | Rating | Supply | W/in2 |
|---|---|---|---|---|
| MTS | 1 in NPT | 0.75 – 3 kW | 120, 240 V, 1 ph | 64 – 86 |
| MTS-1 | 1-1/4 in NPT | 1 – 2 kW | 120, 240 V, 1 ph | 43 – 86 |
| MTS-2 | 2 in NPT | 1.5 – 15 kW | 120, 208, 240, 480 V, 1 ph | 43 – 51 |
| EMTS-3 | 2 in NPT | 3 – 18 kW | 208, 240, 480 V, 1 and 3 ph | 38 – 47 |
| MTS-3 | 2-1/2 in NPT | 3 – 18 kW | 120, 208, 240, 480 V, 1 and 3 ph | 46 – 53 |
The single-phase 1 in MTS series lists MTS-750, MTS-1000, MTS-1250, MTS-1500, MTS-2000, MTS-2500 and MTS-3000, each for 120 V and 240 V, with dimension B growing from 6-5/16 in to 19-7/8 in. Larger series follow the same naming with E2 and E4TP suffixes for the other terminal enclosures.
Choosing between MTS, EMTS and the copper range
Pick stainless when the water or solution would attack copper, for example mildly corrosive rinse, plating or cleaning baths, and check the solution against the stainless grade and passivation before ordering because compatibility depends on temperature and concentration. Use the lower watt density builds for severe solutions, since surface temperature of the sheath rises with watt density. The terminal enclosure follows the area: E1 for general purpose, E4TP for moisture, E2 where an explosion resistant housing is required.
Confirm the tank boss thread, immersion depth, voltage and phase, controller and sensor arrangement and the solution chemistry. Related heating equipment is listed under HVAC and combustion, and the clean-water copper range is on the
page.Documents and quotation
The Chromalox MTS/EMTS catalog sheet with every model and part number is attached. Seven Star LLC, an independent supplier in Muscat, quotes from the model, voltage, phase, kW and enclosure; stock and lead time are confirmed at quotation.
Datasheets & Documents
- Datasheet Chromalox MTS / EMTS Process Water and Corrosive Solutions 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.
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Frequently Asked Questions
They use a passivated stainless steel NPT screw plug and passivated stainless steel elements for process water and corrosive solution heating.
The sheet covers 0.75 kW in the 1 in plug series up to 18 kW in the 2-1/2 in plug series, in single and three phase builds.
No. The heaters are listed without a thermostat and have a thermowell for the control sensor.
E1 general purpose, E2 moisture / explosion resistant and E4TP moisture resistant, selected by a suffix on the model.
High watt density of 43 to 86 W/in2 on smaller series, 38 to 53 W/in2 on larger series, and lower 23 and 15 W/in2 builds for demanding solutions.

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