Thermo Products USDT 2004B User Manual

USDT 2004B

Installation and User’s Guide

Introduction
General Information 2

Installation

Collector Sensor 3
Control Box 5
Power Connection 6
Display Window 6

Operation

Basic Operation of Digital Display 6
Programming the Temperature Range 8
Manual Operation Mode 9
Troubleshooting 10

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Columbia, Maryland 21044

Phone [phone] • Fax [phone]

e-Mail [e-mail]

Basic Revision 8, January 2006

2

U

S2 A1

Introduction

Note: The information supplied in this manual is for guidance only - no part of this may be used
for any agreement, whether express or implied, or to form any contract. Thermo Technologies
reserves the right to change specifications without prior notice.

SDT 2004B is a powerful temperature differential control unit. It uses two temperature

sensors to control a simple solar water heating system; one sensor measures the
temperature of the solar collector whilst the second sensor measures the temperature at the
bottom of the tank.

The control unit has the following basic functions:

• 2 inputs for temperature sensors

• Hi/Low adjustable factory -set temperature programming

• Adjustable (4.1

• Manual override of pump for system testing

• Digital display of all parameters

• System status and diagnostic displays

Operation

The controller uses two sensors. One sensor (S1 in diagram) monitors the collector temperature
whilst the other sensor (S2) monitors the temperature at the bottom of the storage tank. The solar
loop circulation pump runs while the collector temperature
exceeds the tank temperature by an adjustable temperature
difference diff. To avoid overheating, the circulation pump
stops if the tank temperature reaches the adjustable high
limit (T

The pump A1 runs only when the temperature at the
collector sensor location S1 is higher than the return
temperature at location S2 by at least diff (?T). The pump
stops if diff is less than the preset value or, when the
temperature at location S2 has reached the T

) temperature.

MAX

A1 (ON) only when S1 > (S2 + diff) & S2 < T max

o

F to 99 o F) temperature difference ?T

:

MAX

S1

3

T

S

INSTALLATION

Note: This installation procedure is for guidance only, and the installer should verify its
suitability. Make sure that the solar system is physically installed, manually tested, and ready for
controlled operation.

he following safety precautions is strongly recommended:

1. Before attempting to install and operate the unit read this instruction manual carefully.

2. Only suitably qualified personnel should carry out installation and required maintenance.

3. It is recommended that the unit be connected to the power supply via an on/off switch or plug.

4. WARNING: When the unit is connected to the 115 -volt power supply and the cover is

opened, high voltage circuits will be exposed. When installing the unit, all required
connections should be completed and the cover attached to the controller box before turning
the power on. Ensure that all connections are secure. If any maintenance work is required
isolate the unit from the power supply before removing the cover. Never leave the unit
unattended if the cover has been removed and the power supply is connected.

5. Do not exceed unit ratings of 3.15 amps (1/6 HP or 245 Watts).

6. It is advisable to route power cables away from sensor cables.

ensor installation: Temperature sensors may be installed with fluid lines by mounting in a

well or strapping it to the piping directly. For the system to function correctly, it is essential
that the sensors are located and installed properly. Sensors must be well insulated in order to
prevent them from being influenced by the ambient temperature.

When used outdoors, water must not enter the immersion sleeves. Exposure to moisture (e.g.
condensation) can diffuse through the cast resin and damage the sensor.