Love Controls4002A-JFPanel-Mount Digital Temperature Controller, Type J Thermocouple, 0-1000 Degrees F, Dual Potentiometer Setpoints with READ Selector, 120/240 V AC, 7/5 A Relay Output

Product Description

Read directly from the nameplate

The rating label on top of this unit reads:

MODEL: 4002A-JFRANGE: 0-1000 F, thermocouple type JSUPPLY: 120/240 VACLOAD: 7/5 AS/N 9848-25037TUL Listed – Process Control EquipmentIndependent distributor data for the 4002-JF agrees on all the substantive points: J thermocouple input, 0-1000 F range, 7/5 A capacity, 120/240 V AC 50/60 Hz. Two sources converging on the same figures is why these are stated as specification rather than as “typical”.

How the model number breaks down

4002 is the family and configuration, A the build revision, and the JF suffix is the input and scale: J for Type J thermocouple, F for a Fahrenheit scale. That is the pairing to check first – a 4002A-KF or 4002A-JC is a different sensor type or a different temperature scale, and neither will read correctly on your existing probe.

What the front panel tells you about how it works:
The photographs show, from left to right: a SET II adjustment knob, a centre READ selector, a SET I adjustment knob, the LED numeric display with a fixed degrees F legend, the Omega logo, and indicator lamps below. This is the older analogue-setpoint architecture and it is worth understanding before you buy:

Setpoints are set on potentiometers, not typed in. Two knobs give two independent setpoints – typically one control point and one alarm or high-limit point. The READ selector switches the digital display between process value and each setpoint so you can dial a knob and watch the number.Nothing is programmed and nothing is stored. There is no configuration menu, no parameter list and no memory to lose. A pot-setpoint controller is unattractive on a recipe-driven machine and exactly right on a fixed-temperature process where an operator needs to change the setpoint with a screwdriver and no training.The display is a true readout, so you get an indication of actual process temperature rather than just a lamp – which is what separates this from a simple thermostat.

The 7/5 A load rating, in practical terms

The relay output is rated 7 A at the lower supply voltage and 5 A at the higher. That is enough to switch a small heater directly, and not enough for a bank of elements – drive a contactor or a solid-state relay for anything substantial. Switching an inductive load at the contact limit is the usual reason a controller of this vintage arrives with welded contacts.

Brand designation – both names are correct to search:
The bezel and the nameplate on this unit are Omega-branded and the model number is Omega’s. Central Surplus’s record also carries Love Controls against it, and both names appear against the 4002 series in the field, so the brand field has been left as recorded and both are indexed here. Love Controls is a division of Dwyer Instruments; Dwyer and Omega Engineering now sit under the same ownership, which is why the two names cross over in current catalogues and search results. Search either.

Fitting notes

Panel-mount square-bezel unit with rear screw terminals and a plug-in chassis – the module withdraws from the front, so a swap does not disturb field wiring. Confirm the supply-voltage arrangement, the thermocouple polarity and the burnout direction before energising. Type J extension wire and the correct compensating connectors matter on a 0-1000 F range; substituting copper wire at the terminals introduces an offset that no amount of setpoint adjustment will fix properly.

Specifications left blank

Control algorithm (on/off versus proportional), deadband or hysteresis figures, display resolution, accuracy class and enclosure rating are not stated – Love/Omega’s data for the 4002 series is not published in the sources accessible here, and quoting figures borrowed from the later Love 4B/8B/16B or 4C/8C/16C microprocessor series would be wrong, because those are a different generation of instrument. Ask if a specific figure is decisive.

Condition and quantity

One controller, new old stock, as photographed – the condition note records “See Pictures”, so review the images for cosmetic detail. No sensor, mounting hardware, gasket or documentation included.