870 Series SCR Control Panel

The 870 Series SCR Control panel is a fully proportional process temperature control panel that utilizes SCR Power Controllers to modulate the entire heater load directly, varying the heater output from 0 to 100% of the total heater KW. Working on a four second time base, the heater will be energized only for the number of AC cycles necessary to produce the exact amount of heat required. The resulting precision control and rapid response make the 870 Series SCR Control Panel the best choice for applications that must accommodate material flow changes and still provide precise temperature control. The panel is completely assembled, pre-wired, tested, and ready for trouble-free installation and operation. Designed for use in industrial environments and outdoor installations.


Product Inquiry

Standard Features

UL Listed/CSA Approved

NEMA 4/12 painted steel enclosure1

PID self-tuning temperature controller (adjustable process temperature, with thermocouple input)

Over-temperature controller (adjustable temperature limit with thermocouple input)

Disconnecting 50 amp safety contactor for resistive loads (per circuit)

120 VAC control power transformer with primary and secondary fusing

Power circuit fusing

Three-phase, zero cross-fired SCR power controllers

Door interlock disconnect switch

Manual reset pushbutton with built-in pilot light (red) for “OVER-TEMPERATURE” alarm

Selector Switch – ON/OFF with built-in pilot light (green) for “POWER ON” indication. May be possible to customize with other Switches by RAFI.

Terminals for customer supplied remote interlock

Wiring diagram permanently affixed to the inside of the cover

(1) Agency listed for NEMA 4 only.

Optional Features

Control Relays
These relays are activated by safety devices, such as a flow switch or remote shutoff.

Indicator Lights
Additional indicator lights may be specified for visual indication of system status, such as “LOW TEMPERATURE”.

Audible Alarm Package
Includes a horn, pilot light, latching relay and a push button for silencing the horn.

Low Liquid Cutoff
The relay is mounted and wired with sensing probe shipped loose for field installation.

Motor Starter
This package consists of a motor starter for pump motor start-up. Motor starter is internally mounted and field connected to the pump motor.

Special Controllers
The customer may specify the use of special process or over-temperature controllers for a different temperature range, sensor input, control mode, etc.

Panel Heater
A heater and thermostat are provided to prevent condensation and maintain minimum ambient temperature for electrical components.

Wire Markers
Identification markers are attached to both ends of all control and power wires.

Tagging of Internal Parts
Permanent tags are attached to the subpanel near internal parts and marked with component titles as noted on the wiring diagram.

Explosion-Resistant Panel
A cast aluminum enclosure is rated for Class I, Groups C & D and Class II, Groups E, F & G (NEMA 7, 9).

Purged Panels
Type Z for Class I, Division 2 areas; Type X for Class I, Division 1 areas

Special Coatings
Epoxy or other paints may be specified.

Stainless Steel Panel Enclosure (NEMA 4X)
This construction provides extra corrosion resistance for harsh environments1

Ordering Information

Build your catalog number

Catalog Contactor Control Panels

Max KW
Max KW
No. of
Amps Per
Catalog Number with
Maximum Amps
Dimensions (Inches) Estimated
Weight (lbs)
240V/3PH 480V/3PH Height Width Depth
19 39 1 48 AT-870-US0048BK AT-870-US0048BU 24 **24 8 90
39 79 2 48 AT-870-US0096BK AT-870-US0096BU 30 **30 8 140
59 119 3 48 AT-870-US0144BK AT-870-US0144BU 36 **30 8 165
79 159 4 48 AT-870-US0172BK AT-870-US0172BU 42 **30 8 185
99 199 5 48 AT-870-US0240BK AT-870-US0240BU 48 **36 8 275
119 239 6 48 AT-870-US0288BK AT-870-US0288BU 48 **36 8 280
139 279 7 48 AT-870-US0336BK AT-870-US0336BU 60 **36 12 360
159 319 8 48 AT-870-US0384BK AT-870-US0384BU 60 **36 12 365
179 359 9 48 AT-870-US0432BK AT-870-US0432BU *60 **48 12 645
199 399 10 48 AT-870-US0480BK AT-870-US0480BU *60 **48 12 650
219 438 11 48 AT-870-US0528BK AT-870-US0528BU *60 **60 12 745
239 478 12 48 AT-870-US0576BK AT-870-US0576BU *60 **60 12 750

*These panels have double doors and 12” high floor stands.
** Additional 9” clearance required for externally mounted heat sinks which may be mounted on one of both sides of the enclosure.


Closed Tank Heating

Watt Density

Percentage of Wattage

Looking for a
heating solution?

Discuss your project in detail with one of our Application Engineers and they will provide a heating solution perfectly suited to the needs of your application, as well as your budget. Contact us today!

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