RFHAA Modulating Temperature Recorder

This unit is designed to control pneumatically can record two separate temperature variables on a common chart. Relative humidity can be governed through the control of wet and dry bulb temperatures. Two independent control systems in a single case. Humidity and temperature control, output 3-15 psi. Manual reset adjustment with adjustable throttling range 5-25%.
RFHAA Modulating Temperature Recorder
Quick Specification:
  • A two pen, 10" circular chart, temperature recording controller with four switches, providing dual on-off control for heat-cool applications on each pen or heat-cool-humidity applications.
  • Available with 12, 24, or 48 hour, or 7 day rotation times for 125VAC, 60 Hz operation, and others.
  • Seventeen operating ranges covering -30ºF to 1100ºF.
  • Can be panel or surface mounted.
Read more for Mechanical Limits
  • Standard Features
  • Key Specifications
  • Industry/Application
  • Manual
Overview / Design Principle:
This unit is designed to control pneumatically can record two separate temperature variables on a common chart. Relative humidity can be governed through the control of wet and dry bulb temperatures. Two independent control systems in a single case. Humidity and temperature control, output 3-15 psi. Manual reset adjustment with adjustable throttling range 5-25%.
Operation:

The dual RFHAA operates air powered throttling valves regulating the flow of steam, water or gas or actuates other pneumatic devices such as pressure switches or relays. Wet and dry bulbs are recorded when it is used to control temperature and relative humidity.

Two instruments with independent pen arms comprise the control. Pen arms are set at two-hour time differential on a 24 hour chart to prevent interference when recording at or near the same control temperature.

Pen arms move up or down scale in response to the expansion or contraction in the thermal sensing element. As a pen arm enters the throttling range an approaches set point, it changes the effective orifice size in its control mechanism's bleed valve.

The control produces an outpu pressure of 3 to 15 psi, approximately 16 psi input pressure is required to obtain this range. Throttling span is adjustable within the extreme of 5 to 15% of the scale range.

Load arm, inherent in throttling controls, is compensated by a manual reset adjustment.

Standard Features
Chart Diameter: 10"
Chart Marking: Felt Tip Cartridge.
Chart Drive: Electric with toggle switch, or spring wound.
Chart Rotation Periods: 24 and 48 hour, 7 day, other options.
Flush Mount Cutout: 13-1/2" W x 12-11/16" H
Surface Mounting: Mounting brackets included
Electrical Hookup: Terminal block accessible with cover open.
Switch Type: Three wire SPDT, 2 per each mechanism.
Switch Sensitivities: Normal 1% of range (#79) standard. Super Sensitive (#73) 0.5% or range-field installable.
Conduit Openings: One 7/8" diameter hole on each side of the case for 1/2" conduit fitting; drill guide hole spotted in the rear of the case showing optional rear opening location.
Air Output Pressure: 3 to 15 psi.
Air Consumption: 12 cfh maximum per mechanism.
Throttling Span: Adjustable from 7 to 35% of element range.
Load Error Adjustment: Manual reset for load error compensation.
Physical Characteristics
Dimensions: 15-1/8" W x 13-3/16" H x 4-7/8" D
Approx. Net Weight: 9 lbs
Approx. Ship Weight: 14 lbs
Warranty
1 year
  • Basic recording capability for diverse industrial heat and cooling applications
  • Mobile Refridgeration
 
5672 Bolsa Avenue Huntington Beach, CA 92649 - USA - Ph (714) 622-2000 - Fax (714) 622-2001