Siemens 188 Unit Mounted Thermostats
Unit Mounted Thermostats
188
The 188 Unit Mounted Thermostat is a gradual acting thermostat with a remote bulb operating on the forcebalance principle, using pneumatic feedback to obtain linearity and maintain selected room temperature by positioning pneumatic devices to control heating or cooling.
• Liquid-filled thermal system temperature sensing element
• Durable die-cast metal case with rugged setpoint knob
• Adjustable sensitivity
• Universal mounting bracket for easy installation
• Integral adjustable limit stops
• Available as: – Direct Acting only (Heating) – Reverse Acting only (Cooling) – Heat or Cool depending on supply air pressure
Select a link under the "item" tab below to order.
| Cat # | Type | Control Action | Changeover Pressure | Average Air Usage |
| 188-0031 | Single Setpoint | Direct Acting / 25 psi (172 kPa) | - | 40 scim (11 ml/s) |
| 188-0024 | Single Setpoint | Reverse Acting (Cooling) 18 psi | - | 20 scim (5 ml/s) |
| 188-0030 | Heat/Cool | Direct Acting / Reverse Acting (Cooling) 18 psi (124 kPa) | - | 40 scim (11 ml/s) |
| 188-0033 | Heat/Cool | Retroline Direct Acting/Reverse Acting 18 psi (124 kPa) / 13 psi (90 kPa). Retroline replacement for Honeywell LP916BXXXX. | 15 psi (103 kPa) | 40 scim (11 ml/s) |
| 188-0034 | Heat/Cool | Retroline Direct Acting/Reverse Acting 20 psi (138 kPa) / 15 psi (103 kPa). Retroline replacement for Johnson Controls T-3300-2. | 17 psi (117 kPa) | 40 scim (11 ml/s) |
| Control Action | Heating/Cooling, Direct and Reverse; Direct only; Reverse only |
|
| Operating Range | 60 to 85°F (15.5 to 29.4°C) | |
| Operating Pressure | 30 psi (207 kPa) max. | |
| Adjustment Sensitivity | 1 to 5.25 psi/°F (12 to 65 kPa/°C) | |
| Factory Sensitivity Setting | 2.25 psi/°F (28 kPa/°C) | |
| Temperature Response | 0.2°F (0.1°C) | |
| Maximum Ambient Temperature | ||
| Case | 135°F (57.2°C) | |
| Bulb | 231°F (111°C) | |
| Scale Graduations | 1°F (0.55°C) | |
| Nominal Air Supply Pressure | ||
| Direct or Reverse Acting | 25 psi (172 kPa) | |
| Heating/Cooling | 25 psi (172 kPa)/18 psi (124 kPa) | |
| Average Air Usage | ||
| 20 scim Restrictor | 25 scim (6.8 ml/s) | |
| 40 scim Restrictor | 45 scim (12.2 ml/s) | |
| Air Connections | 1/4" (6 mm) Brass barbed for polyethylene tubing | |
| Bulb Size | 3/8" Diameter x 3-1/2" L (9.5 mm Diameter x 89 mm L) |
|
| Capillary Length | 48" (121.9 cm) approx. | |
| Finish | Corrosion-resistant Zinc Chromate | |
| Dimensions (case) | ||
| Heating/Cooling, Reverse Acting | 3.1" W x 2.4" H x 2.13" D (100 mm W x 61 mm H x 54 mm D) |
|
| Direct Acting | 3.1" W x 2.4" H x 1.38" D (100 mm W x 61 mm H x 35 mm D) |
|
| Shipping Weight | 3.0 lb. (1.36 kg) | |
