Siemens Powers TH 188 Technical Instructions

TM
Powers
TH 188 Unit Mounted Thermostat
Description
Features
Application
Product Numbers
Controls
The TH 188 Unit Mounted Thermostat is a remote bulb, gradual acting pneumatic
instrument that maintains a pre-selected temperature by positioning pneumatic devices
that control a heating or cooling medium.
Replacement thermostats are available for Honeywell models LP916Bxxxx and Johnson
Controls model T-3300-2.
•
Liquid filled sensing element
•
Direct acting (DA), reverse acting (RA), and heating-cooling models (HC)
•
Mounting bracket provided
The TH 188 thermostat is mounted in fan coil units and unit ventilators to control a space
temperature in applications where a wall thermostat cannot be used.
In unit ventilator applications, where the unit mounted thermostat pilots a Limitem, use a
thermostat having a 40 scim (11ml/s) restrictor. The Limitem has a built-in bleed to
prevent control air from being trapped.
To assure good control, the remote bulb sensing element must be located so that space
air passes over it continuously.
Thermostat Action
and
Model Number
HC (DA & RA) TH 188 HC
DA TH 188D
RA TH 188R
Honeywell HC LP916Bxxxx
Johnson HC T-3300-2
*Use 188-0024, but change restrictor.
Technical Instructions
Document No. 155-064P25
Table 1.
Product Number
With 20 Scim With 40 Scim
(5.5 ml/s)
Restrictor Restrictor
---
---
188-0024
---
---
TH 188-2
April 1, 2005
(11 ml/s)
188-0030
188-0031
*
188-0033
188-0034
Siemens Industry, Inc.