An Open-Box IS220PTCCH1A Thermocouple Pack

This IS220PTCCH1A is a new-surplus, open-box thermocouple input pack for the GE Mark VIe system — unused, but supplied outside its original sealed carton. It is the same thermocouple (TC) input pack that Mark VIe turbines rely on to convert millivolt thermocouple signals into usable temperature data, and it makes a sensible shelf spare for a site that wants an unused pack ready for the next temperature-channel event.

The pack mounts on a thermocouple terminal board in the TBTC family and connects through a 37-pin connector, with a three-pin power input and dual RJ45 IONet ports. One pack reads up to 12 thermocouples; two packs on a suitable terminal board reach 24. The acquisition board is purpose-built for TC measurement, with a 16-bit converter and cold-junction compensation provided at the terminal board, and the reported input types cover the common E, J, K, and S thermocouples (some sources also list T) over roughly a -8 to +45 mV span.

The Reading Is Wrong — But Is It the Pack?

An open-box spare is only worth installing if the pack is genuinely the problem. On thermocouple inputs it frequently is not. Run this check first:

• Sensor: a worn or open thermocouple is the single most common cause of a bad channel. Compare against a nearby TC.
• Cold junction: the reference junction lives at the terminal board; a gradient or compensation fault there skews readings across the board, which can look like a pack failure when every channel drifts at once.
• Extension wire and polarity: the wrong wire type or a reversed pair produces a wrong-but-plausible reading.
• Terminal board, power, IONet: check the TBTC terminations, the three-pin power feed, and the Ethernet path before condemning the electronics.

The status LEDs and ToolboxST diagnostics will normally tell you whether you are looking at a field fault, a configuration mismatch, or a real pack failure.

H1A in the IS220 Thermocouple Numbering Scheme

Read the number as blocks: IS220 is the Mark VIe distributed I/O pack, PTCC is the thermocouple input function, and H1A is the group-and-revision suffix. The trailing letter steps forward with hardware revisions, so match the suffix and the printed revision when replacing a pack. The GE Speedtronic Part Number Decoder walks through the whole convention.

TMR, Cold Junctions, and Companion Hardware

Thermocouple packs are used in simplex, dual, and triple-modular-redundant (TMR) arrangements. In a TMR thermocouple setup, three packs — one each for the <R>, <S>, and <T> controllers — read the field through their own cold junctions, while the channel count available to the controller stays at 12. The RTD-based PRTD pack is the PTCC's counterpart on the resistance-sensor side. For system-generation background, see Mark V vs Mark VI: DS200 to IS200, and browse GE Mark VI IS200 Boards and GE Speedtronic Turbine Control Boards.

Speed Up Your Quote With These Details

• Full part number and suffix (IS220PTCCH1A) with the label revision.
• A photo of the label.
• Turbine model and Mark VIe generation.
• Quantity and how urgent the need is.

Get an IS220PTCCH1A Quote in 24 Hours

This IS220PTCCH1A is new-surplus, open-box stock, factory packaged and covered by the warranty below. Use Request a Quote to send your details; we reply within 24 hours, ship worldwide on DDP terms, and accept purchase orders.