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Temperature Controls and Timers with LED display

THERMOSTAT with LED Display and Relay

Model series SDH-4PB
With 1 or 2 external temperature sensors
Models for 120Vac, 208-250Vac, 
12V and 24V AC/DC
Output load :
up to 30 Amp / 250Vac.
Optional Remote Control + Display Panel
Temperature range: -40F (-40C ) to 255F ( 124C )
Higher custom ranges avilable up to 960F ( 515C )
Heating and/or Cooling and differential modes

Thermostat mounting in 1-gang box

Installation example 
in 1-gang wiring box

SDH-4PB Digital Thermostat face plates

3 push-buttons:

Black, White or Custom
labels available

Metal Face
Dim's:  4.5" x 2.75" x 0.5"
115mm x 70mm x 12mm

Thermostat with Vandal Proof push buttons

SDH-4PB Digital Thermostat with Vandal Proof push buttons


Sauna Control Panel
Infra Red Sauna Control
Spa Controller
Steam Bath Control
Heater Thermostat
HVAC ​Thermostat
Refrigeration ​Thermostat
Water Tank Temperature Control
Yoga Room ​Thermostat
Freezer Temperature Control
Solar Water Heater ​Thermostat
Ventilation Control
Chiller ​Thermostat
Pool Temperature Display
Train Car ​Thermostat
Bus Cabin ​Thermostat
Greenhouse Temperature Control
Temperature Monitoring and Alarm
Heat / Cool Process Control
Temperature Difference Control


  • Accurate digital temperature control
  • Sensor wire up to 500ft (150M)
  • Heating or Cooling mode
  • Preset memory
  • Automatic self-calibration
  • Programmable temperature limits
  • Large LED display
  • Large push-buttons
  • Quiet operation
  • Powerful internal relay
  • Simple wiring
  • Supply and load can be different voltage
  • Message on display when error detected


  • Remote control panel with display
  • Extended temperature ranges
  • Automatic or manual start
  • Special custom functionality
  • Low or High power internal relay
  • Variety of temperature sensors
  • Programmable operating features
  • Red, green or blue LED display
  • Additional input for external contact
  • Additonal input for second temp. sensor
  • Large Vandal-proof push-buttons
  • Custom designed face label
  • Optional internal buzzer
Temperature Sensor Probes
Temperature sensor probes for thermostat Digital Thermostat flush mounting Digital Thermostat Semi-Flush mounting
Flush face temperature controller installation
in wall or panel
Semi-Flush face temperature controller installation
in wall or panel

Example of available models
Wiring e​xtendable
up to 500 ft ( 150M)

Remote ON - OFF button
Temperature Sensor Protection
Mounting Guard for Temperature Sensor probes Temperature sensor with flange Plastic guard for temperature sensor probes
Temperature Sensor
with Flange
Remote ON - OFF button
with LED indicator

Optional Plate-Guard
for standard sensor probes.
Plastic model PPP-4
and SS model PPS-4

Optional Plastic Guard
for standard sensor probes.
Model PG-5

SDH-4PB Digital Thermostat wiring examples

More SDH-4 Thermostat Wiring Examples

Line Thermostat wiring for up to 30Amp, 250V loads Thermostat basic wiring for up to 30Amps, 250V loads

Simple SDH-4PB line thermostat wiring
for up to 30Amp loads

Basic SDH-4PB thermostat wiring
for up to 30 Amps load

Heater Thermostat wiring with contactor for very high loads Thermostat or Thermometer wiring with alarm buzzer

SDH-4PB thermostat wiring
with Alarm buzzer

Extended SDH-4PB thermostat wiring
for very high power loads
using external contactor

Thermostat wiring with low voltage supply and for very high power loads Digital Heater Thermostat wiring with two temperature sensors

Special SDH-4PB thermostat wiring
for loads up to 30Amp
with two temperature sensors

Extended SDH-4PB thermostat wiring
for very high power loads using external contactor
and with separate low voltage supply

THERMOSTAT Description

Download SDH-4PB Thermostat Specifications

SDH-4PB is a digital temperature controller designed for Heating and/or Cooling.
It has an internal, accurate, programmable thermostat processor, that is self-calibrating and does not require any maintenance or adjustments.
The thermostat controls one on-board relay with contacts rated for up to 30Amp, 250Vac load max. Optionally an internal alarm buzzer or a low power relay can be ordered for special applications to control loads of up to 1Amp, 250Vac max. for instance to activate other external devices.
The high power or the optional low power relay contacts can be wired up to control Heaters, HVAC and other loads like a Fan, Motor, Pump, etc...
The relay contacts can be wired up as completely isolated from the controller's supply, so the supply voltage can be different than the voltages on the load.
In order to switch very high loads, the relay contacts can be wired up to control the coil of an external contactor.
An additional, dry contact input can be ordered for external Start/Stop control switch or other applications, like for instance a water level sensor switch.
Also, an additional, temperature sensor can be installed for special applications like a temperature difference control or to sense the temperature at two separate locations.
The controller is operated and the temperature setpoints are preset by pressing the corresponding keys on the control panel face. The preset values are stored in internal memory.
A variety of the controller's operating configurations, temperature ranges and limits are also programmable via the face plate keys.
Customized face plates and special, vandal proof push-buttons are available.
The large 3-digit LED display shows temperature preset values, current temperature and other indications of operation. The LED display can be ordered in RED, GREEN or BLUE color.
Note, that SDH-4PB controllers are designed to eliminate almost completely the EMF ( Electro Magnetic Field ) radiation.

THERMOSTAT and TIMER Numbering System

Thermostat and Timer Numbering System