| Features | 233 Series | 236 Series | 254 Series |
| Hazardous Location NEC Classifications | Class I, Divisions 1 and 2, Groups C and D
Class II, Divisions 1 and 2, Groups E, F and G
Class 1, Zones 1 and 2, Groups IIB | Class I, Divisions 1 and 2, Group D
Class 1, Zones 1 and 2, Group IIA | Class I, Divisions 1 and 2, Groups B, C and D
Class II, Divisions 1 and 2, Groups E, F and G
Class 1, Zones 1 and 2, Groups IIC |
| Ignition Temperature Code | T3C
320°F (160°C) | T3
392°F (200°C) (Varies with KW) | T3C
320°F (160°C) (Varies with classification) |
| KW Range | Up to 30 KW | Up to 12KW | Up to 9.5 KW |
| Standard Built-In Overtemperature Protection | Dual overtemperature protection with automatic and manual reset thermal cutouts | Primary and secondary automatic reset cutouts with fan relay | Primary automatic reset cutout |
| Other Standard Built-In Controls | Controlling contactor, control circuit transformer | Controlling contactor | None |
| Standard Control Voltage | 24V | 120V | Maximum 277V |
| Single Point Line Voltage Connection for Incoming Power | Yes | Separate 120V motor line required | Yes |
| Optional Built-In Controls |
| Thermostat | Yes | Yes | Yes |
| Disconnect Switch | Yes | No | No |
| Selector Switch | Yes | No | No |
| Manual Reset Cutout | Standard | Yes | No |
| "Heater On" Pilot Light | Yes | No | No |
| "Warning" Pilot Light | Yes | No | No |
| Control Circuit Transformer | Standard | No | Yes |
| Standard Construction |
| Heater Assembly | Liquid-to-air heat exchanger, steel tube with aluminum fins, propylene glycol, immersion heater | Stainless steel finned tubular elements | Heater core enclosed in copper tube with large aluminum fins |
| Cabinet/Housing | Powder coated galvanized steel | Stainless steel | Powder coated galvanized steel |
| NEMA 7,9 Control Enclosure | Cast aluminum | Cast aluminum | Cast aluminum |
| Mounting Brackets | Wall, ceiling or pole mounting kits (optional) | Swivel mounting bracket (standard) | Wall mounting bracket (standard) |
| Optional Constructions |
| Dirty Duty Corrosion Resistant | Choice of 316SS Construction or Heresite® coating | Yes | Wet locations (NEMA 3) iridite coated elements |
| 50 Hertz Motor | Yes | No | N/A |
| Agency Approvals |
| CSA (Canadian Standards Association) | Yes | Yes | Yes |
| ABS (American Bureau of Shipping) | No | Yes | Yes |
