Product Overview
An Indeeco refrigeration defrost heater is a small-diameter tubular element that melts frost and ice from the evaporator coils, fins, and condensate drain pans of commercial refrigeration equipment. It comes in two styles: a field-bendable .250″ straight-length heater that clamps to coils and pipes or forms into a drain pan, and a .490″ cartridge type that inserts into holes drilled in the coil fins. Both carry molded waterproof terminals for the wet defrost environment, and the straight-length heater is UL and CSA listed. The heater is cycled by an external defrost control (time clock or manual), and a molded-in limit or fusible link is available for sheath-temperature protection. Indeeco has built electric defrost heaters since 1929.
Related Indeeco options & matched controls
Tubular & Finned-Tubular Elements — the general-purpose tubular element family these defrost heaters descend from
Heat Trace — pipe and vessel freeze protection and process-temperature maintenance
Immersion Heaters — sealed tubular elements dropped into a tank or vessel
Heater Control Panels — matched defrost / contactor / SCR control packages
Key Features & Benefits
- Bends to your coil in the field — an installer shapes the straight-length heater to follow the evaporator coil or wrap a drain pan on the spot — no custom-formed part to order and wait for. One stock heater fits geometries you would otherwise have to special-order.
- Sealed to live in a wet, frosting environment — molded waterproof terminals and a watertight sheath are built for the condensate, melt-water, and humidity that come with defrost duty; the mold is rated for moist locations. The failure point on a defrost heater is water in the terminal — this one is sealed against it.
- Two styles cover the two ways frost forms — the bendable straight length handles coil-surface and drain-pan frost; the rigid cartridge slides into holes in the fins to melt ice from inside the coil pack. Pick the style by where the ice is, not by what is in stock.
- Listed and stocked for commercial refrigeration — agency-listed and offered as stock part numbers in common wattages and lengths (the listings are in the specifications), so a standard job ships without an engineering cycle. Catalog ratings for the routine jobs; the factory for the rest.
- Built to spec for OEM and odd jobs — custom cold sections, alternate sheath alloys, inline fusing, a welded ground, single- or double-ended leads, and a molded-in limit/fusible link are all on the option list, with OEM quantity pricing. A platform a coil builder can standardize on, not a one-off.
Specifications
- Operating principle
- Electric resistance (Joule) heating in a small-diameter tubular sheath. The heater is clamped to, formed against, or inserted into the part to be de-iced, and its surface heat melts frost and ice from refrigeration evaporator coils, fins, and condensate drain pans. Indeeco has designed and built electric defrost heaters since 1929.
- Heater styles
- Two styles on one platform: a straight-length heater (a .250″ stainless-steel sheath, field-bendable) that clamps to coils and pipes or forms into drain pans, and a cartridge type (a single-ended .490″ copper or stainless sheath) that inserts into holes provided in the coil fins.
- Mounting / installation
- Straight length: clamps directly to evaporator coils, or forms into a drain pan to keep condensate from freezing — the molded terminals must be located above standing water. Cartridge type: inserts into a .500″ minimum-diameter hole drilled in the coil fins, with the mold located above standing water.
- Field forming / bending
- The straight-length heater is fully annealed so it can be bent to shape in the field to follow the coil or pan geometry. The cartridge type is a rigid single-ended insert and is not field-formed.
- Sheath diameter
- Straight length: .250″ diameter. Cartridge type: .490″ diameter (also available in .430″ on special order). Other element diameters are available — consult the factory.
- Sheath materials
- Straight length: copper or stainless steel (the stock catalog table lists both, with construction-prose default .250″ stainless). Cartridge type: copper or stainless steel. Elements are also available in copper, Incoloy, or stainless steel as a value-added option.
- Element construction
- Straight length: a continuous straight stainless sheath with molded waterproof terminals. Cartridge type: a resistance coil centered in the sheath, filled with magnesium oxide (MgO) and swaged to compact the insulation around the coil; the end opposite the terminal is sealed watertight.
- Cold (unheated) section
- Straight length: a 7″ cold (unheated) section at each end. Cartridge type: a 2-1/2″ cold section at the terminal end. Custom cold sections are available.
- Leads & terminals
- Molded waterproof terminals on both styles. Straight length: 24″ leads of 600 V, 105°C appliance wire. Cartridge type: 10″ leads. Single-ended or double-ended molded terminations are available.
- Terminal / mold temperature rating
- The molded terminal (a Valox® mold on the straight-length heater) is rated 120°C for moist locations.
- Watt density
- The straight-length heater runs approximately 11 W/in² — a low, frost-melting density suited to direct coil and drain-pan contact.
- Wattage range
- Straight length: stock ratings from 220 W to 1500 W at 240 V (sheath lengths 9″ to 90″). Cartridge type: stock ratings from 300 W to 1500 W (sheath lengths 45″ to 216″). See the catalog tables below; other wattages and sheath lengths are available — consult the factory.
- Voltage
- Straight length: 240 V (stock). Cartridge type: 120 V or 240 V (stock). See the catalog tables below.
- Stock catalog models
- Stocked under part numbers in the 546X- series (straight length) and the 532Z- series (cartridge type) — see the catalog tables below. Indeeco stock no. 54-1000-80.
Cartridge Type — Stock Catalog
| Wattage | Volts | Sheath length | Heated length | Catalog no. |
|---|---|---|---|---|
| 300 W | 120 V | 45″ | 31″ | 532Z-243314 |
| 450 W | 120 V | 68″ | 54″ | 532Z-243315 |
| 675 W | 120 V | 91″ | 77″ | 532Z-243316 |
| 675 W | 240 V | 91″ | 77″ | 532Z-243317 |
| 850 W | 120 V | 105″ | 91″ | 532Z-243318 |
| 850 W | 240 V | 105″ | 91″ | 532Z-243319 |
| 1000 W | 240 V | 118″ | 104″ | 532Z-243320 |
| 1250 W | 240 V | 188″ | 174″ | 532Z-243321 |
| 1350 W | 240 V | 150″ | 136″ | 532Z-243322 |
| 1500 W | 240 V | 216″ | 202″ | 532Z-243323 |
- Control & defrost cycling
- The heater is cycled by an external defrost control — a defrost time clock or a manual defrost control — not by an on-board thermostat. Inline fusing and a grounding wire welded to the sheath are available.
- Over-temperature protection options
- A bimetal automatic limit control and/or a fusible link can be molded into a waterproof mold for sheath-temperature sensing — an option for over-temperature protection on the element itself.
- Value-added options
- Value-added options: custom cold sections; elements in copper, Incoloy, or stainless steel; factory-installed wire terminations; inline fusing; a grounding wire welded to the sheath; single- or double-ended molded waterproof terminals; and molded-in bimetal limit and/or fusible-link sheath sensing. OEM quantity discounts are available.
- Approvals & listings
- The straight-length heater is UL and CSA listed; its Valox® mold is rated 120°C for moist locations. (Custom configurations and the cartridge-type stock ratings are noted in the catalog as available without an agency listing — confirm the listing required for your build with the quote.)
- Build & lead time
- Custom build-to-order — no published price list, quote-only. Lead times typically run about 3 to 14 weeks depending on configuration, hazardous-area documentation, and code-stamp requirements.
Common Applications
- Electric defrost of evaporator coils in commercial refrigeration equipment
- Drain-pan / condensate-pan heating to prevent re-freezing of melt-water
- Coil-fin cartridge defrost — inserted into holes provided in the fin pack
- Clamped to pipes or tanks to promote drainage and prevent freezing
- OEM refrigeration and cold-storage equipment requiring stock or custom defrost elements
Fit limit: a defrost heater is a low-watt-density surface heater for melting frost and ice on refrigeration coils and pans — cycle it on a defrost control and keep its molded terminal above standing water (see Design & Selection Considerations). To heat a fluid held in a tank or piped through a vessel, the Indeeco tank, immersion, or circulation builds are the answer.
Design & Selection Considerations
- Keep the molded terminal above standing water — the catalog is explicit: locate the molded terminal (and the cartridge mold) above any standing water. Water sitting against the termination is the classic way a defrost heater fails. Orient the heater so the seal never sits in melt-water or condensate.
- Cycle it on a defrost control — it has no on-board thermostat — the heater is meant to run only during the defrost cycle, switched by a time clock or manual defrost control; it carries no built-in thermostat. Leave it energized continuously and it overheats. The defrost control, not the heater, decides when it is on.
- Add a molded limit or fusible link where over-temperature is a risk — for a fail-safe against a stuck control or a dry coil, the bimetal limit and/or fusible link can be molded right into the terminal for sheath-temperature sensing. Where loss of airflow or a controls fault could let the sheath run hot, spec the molded-in protection.
- Match the style and lead exit to the coil pack — the straight length clamps to or forms around the coil; the cartridge inserts into a .500″-minimum drilled hole — confirm the fin hole diameter and the lead-exit side before ordering, since single- or double-ended terminations are a build choice. The mechanical fit (hole size, lead exit, cold-section length) is set at order time, not in the field.
- Bend the annealed heater carefully, once — the straight-length sheath is annealed for field forming, but it is still a metal-sheathed element — bend it smoothly to the intended radius rather than working it back and forth, which fatigues the sheath and can crack the seal. Form it to the coil in one deliberate pass.
To spec the right Indeeco refrigeration defrost heater:
Use the input form to tell us the style you need (straight-length to clamp/form, or cartridge to insert), the evaporator coil or drain-pan geometry it must follow, the required wattage and voltage, the sheath length and any field-bend shape, the sheath material (stainless, copper, or Incoloy), the cold-section and lead requirements, and whether you need a molded-in limit or fusible link — and we’ll spec the right Indeeco defrost heater, stock or custom.
Electric Heating Application Sheet ›Talk to an engineer directly — Scott Prater, Principal · 917-580-0878 · scott@pratertechnical.com
Specifications compiled by Prater Technical Partners from Aspeq Heating Group product datasheets.