TH 188 Unit Mounted Thermostats
Product Description
The TH 188 Unit Mounted Thermostat is a remote
bulb, gradual acting pneumatic instrument that
maintains a preselected room temperature by
positioning pneumatic devices that control heating or
cooling medium. This thermostat has a liquid filled
thermal system.
Product Numbers
TH 188R Reverse Acting (RA)
20 scim (5.5 ml/s) restrictor
TH 188HC Heating (direct)/Cooling
(reverse) 40 scim (11 ml/s) restrictor
TH 188D Direct Acting (DA)
40 scim (11 ml/s) restrictor
Replacement for Honeywell models
LP916BXXXX
Heating (direct)/Cooling (reverse)
40 scim (11 ml/s) restrictor
Replacement for Johnson Controls
T-3300-2
Heating (direct)/Cooling (reverse)
40 scim (11 ml/s) restrictor
Required Tools
•
Medium flat-blade screwdriver
•
Small drill
Expected Installation Time
90 minutes (1 hour and 30 minutes)
Installation
A mounting bracket is included for mounting the
thermostat in various units.
1.
Fasten the mounting bracket to the partition
with two sheet metal screws included with the
thermostat. Figure 1 shows a typical
installation.
188-0024
Figure 1. Thermostat and Mounting Bracket.
188-0030
NOTE:
188-0031
188-0033
188-0034
2. Mount the remote sensing bulb in the air stream
of the return air (near the inlet of the fan).
Avoid metal to metal contact between the bulb
and the unit to prevent damage to the soft
copper sensing bulb from unit vibration.
Installation Instructions
Document No. 129-129
Rev. 3, August, 2000
If there is not enough room to mount the
thermostat in a convenient location, or if
the set point dial must be in the same
compartment as the fan switch, order an
extension shaft kit (Part Number 188-101).
See Figure 2 .
Using the extension shaft, mount the
thermostat in any convenient location
within eight inches of the control
compartment.
Figure 2. Use of Shaft Extension.
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