Description
W91 & W94 – Direct-Operated Mixing & Diverting Temperature Regulators
The Watson McDaniel W91 & W94 Series are direct-operated temperature regulators designed for precise control in mixing or diverting applications. These regulators combine a rugged valve body with a thermal actuator to modulate temperature automatically without the need for external power. Built for reliability, accuracy, and long service life, they are widely used in industrial process control, heat transfer systems, and temperature-regulated fluid applications.
Product Overview
The W91 (Non-Indicating) and W94 (Indicating) models utilize the same high-performance valve platform but differ in display features. Each assembly includes a valve body, thermal actuator, copper bulb, and an 8 ft. capillary as standard. A wide range of temperature spans and bulb configurations allows for precise adaptation to various system requirements.
Key Features
- Self-operated—no external power source required
- Available in mixing or diverting flow arrangements
- Rugged thermal actuator with copper sensing bulb
- Wide selection of temperature ranges (01–14)
- Indicating (W94) and Non-Indicating (W91) versions
- Available in NPT and 125# flanged connections up to 4 inches
- Factory-assembled for quick installation
- Optional bulb lengths, capillary lengths, and insertion bulbs
Applications
- Blending hot and cold fluids to maintain a stable outlet temperature
- Diverting flow based on temperature changes in process lines
- Heat exchangers and cooling systems
- Process temperature control in industrial equipment
- General industrial thermal regulation requiring accuracy and durability
Temperature Ranges
Available ranges span from 20°F to 480°F (-7°C to 250°C), depending on the range code. The recommended operating span falls within the upper half of each nominal range for optimum performance.
| Range Code | Nominal Temperature Range |
|---|---|
| 01 | 20–70°F / -10–20°C |
| 02 | 40–90°F / 5–30°C |
| 03 | 50–140°F / 10–60°C |
| 04 | 70–160°F / 20–70°C |
| 05 | 75–165°F / 25–75°C |
| 06 | 100–200°F / 40–90°C |
| 07 | 125–215°F / 50–105°C |
| 08 | 195–250°F / 90–120°C |
| 09 | 200–280°F / 95–135°C |
| 10 | 225–315°F / 105–155°C |
| 11 | 255–370°F / 125–185°C |
| 12 | 295–420°F / 145–215°C |
| 13 | 325–450°F / 160–230°C |
| 14 | 400–480°F / 205–255°C |
Model Configuration
Models are configured by selecting the actuator type, temperature range, capillary length, bulb type, and valve body configuration. Sample configuration: W91-05-12-S15-A45.
- W91 – Non-indicating actuator
- W94 – Indicating dial actuator
- Temperature Range: 01–14
- Capillary Length: 8, 12, 16, 20, or 24 feet
- Bulb Types: Standard copper bulb (S15) or insertion bulbs (SB15/SB16)
- Valve Body Selection: NPT or flanged sizes from 1/2" to 4"
Valve Body Options
Valve bodies are available for both mixing and diverting applications. Proper inlet pressure balancing is recommended for best performance.
Valve Sizes
- 1/2" to 2" NPT with integral union
- 2-1/2", 3", and 4" available in 125# flanged connections
- Maximum operating pressure (PMO): 125–250 PSI depending on size
Bulb and Capillary Options
- Standard copper sensing bulb with 8 ft. capillary
- Optional 12, 16, 20, or 24 ft. capillary lengths
- Insertion bulbs for immersion wells (SB15, SB16)
- Extra charges apply for extended lengths or insertion bulbs
Warnings & Notes
Caution: 3-Way valves are not designed for use in steam applications.
Thermowells for W91/W94 models are sold separately.
Specifications, pricing, and configurations are based on manufacturer-provided technical documentation.