ITCH Assembly


The ITCH (Instrument Temperature Control Heater) Assembly is 100% mechanical, operating solely based on ambient and/or fluid temperature changes controlled by a wax motor.

The thermostatic wax actuator located at one extreme of the TV/SC-A valve operates like the thermostat in an oven, automatically senses the internal enclosure temperature, and regulates steam flow to the heater coil to maintain the desired temperature. The TV/HAT at the steam inlet keeps the steam supply hot to prevent freezing even when the TV/SC-A valve is closed. The TV/HAT at the coil outlet regulates condensate discharge temperature for maximum economy with minimized overheating potential.

The ITCH Heater Assembly comes complete with a steam coil, mounting bracket, and TV/SC-A valve assembly, two TV/HAT valves, and two weather-tight bulkhead fittings for 3/8 tubing connections.

The TV/SC-A and TV/SC-I valves (with external connections) are also available separately if you do not require a complete assembly.

Instrument Temperature Control

Typical Applications

ITCH Assembly - Instrument Temperature Control

The ITCH Assembly, instrument temperature control valve assures accurate temperature control in an instrument or analyzer enclosure. It will maintain enclosure temperature accurately over a wide range of ambient temperatures with steam supply pressures from 15 PSIG (1 BAR) to 200 PSIG (13.8 BAR) without danger of overheating delicate instruments.

This self-contained unit provides a reliable, economical alternative to costly, hazardous electric heating. No special NEMA-7 or 9 housings are required even in potentially explosive environments.

Design Features

  • Exclusive self-actuating Thermoloid® blend wax thermal actuator
  • All stainless-steel construction
  • Compact, low mass – fast response
  • Corrosion-resistant – long service life
  • Ram-type plug for tight reliable shutoff
  • Operating temperatures unaffected by variable inlet pressures
  • Wide choice of set-points available


  • Self-operating – no external power source required
  • Economically controls steam flow
  • Maintain enclosure temperature accurately over a wide range of ambient temperatures
  • Eliminates danger of overheating
  • Complete kit with standard tube connections for quick and easy installation






  1. Full open temperatures “XXX” available: 35°F, 40°F, 50°F, 55°F, 60°F, 65°F, 75°F, 85°F, 90°F, 95°F, 100°F, 105°F, 110°F, 125°F, 130°F, 140°F, 150°F, 155°F, 160°F, 170°F, 180°F, 190°F and 200°F
    1. Closing temperature is typically 10°F above opening temperature


  • Size: ⅜”
  • Maximum Pressure: 200 PSIG (13.8 BAR)
  • Maximum Temperature: 250°F (121°C)


ITCH Assembly Product Sheet
ITCH Assembly Installation and Maintenance Instructions
Instrument and Process Temperature Control Brochure