Thermo Products USDT2004 User Manual

USDT 2004

Installation and User’s Guide

Introduction
General Information 2

Installation 3

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

Operation

Basic Operation (Factory Setting for Only Two Sensors) 7
Manual Operation Mode 8
Three Sensor Operation 9
Sensor Selection 11
Alarm Functions and Diagnostics 12
Energy Calculations 13

Troubleshooting 14

 Thermo Technologies

5560 Sterrett Place • Suite 115

Columbia, Maryland 21044

Phone [phone] • Fax [phone]

e-Mail [e-mail]

Revision 7, November 2005

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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 2004 is a powerful temperature differential control unit. It has *two programs and
may be used in a wide range of applications:

PROGRAM 0 – This program is USDT 2004's basic program. Set at the factory, it uses two
sensors to control a simple solar water heating system.

PROGRAM 1- This program allows the user to customize USDT 2004 for applications where a
third sensor is required. With this program you may, for example, measure the flow rate or the
temperature of the storage tank (T3, top of the tank).

*USDT 2004 has additional programs available for a wide variety of advanced applications, these programs are not

supported at this time.

The control unit has the following functions:

• 2 inputs for temperature sensors (PROGRAM 0)

• 1 input for flow rate measurement or additional temperature sensor (PROGRAM 1)

• BTU meter capability for constant flow rate or with a flow meter

• Adjustable hysteresises dependant on temperature

• Adjustable (-3

• Adjustable (200 o F to 299 o F) overheating protection

• Adjustable (4.1

• Manual override of pump for system testing

• Digital display of all parameters

• System status and diagnostic displays

Program 0 – Two Sensor Operation (Factory Setting)

Program 0 monitors the collector temperature (T1, at S1) and the return temperature (T2, at S2 ,
bottom of the storage tank). The solar loop circulation pump runs while the collector temperature
exceeds the return temperature by an adjustable
temperature difference diff. To avoid overheating, the
circulation pump stops if the return temperature (T2)
reaches the adjustable high limit (T
temperature hysteresis (a lagging in the set-point) may
over-ride diff to avoid pump cycling.

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

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

o

F to 41

o

o

F) frost protection

F to 99 o F) temperature difference ?T

) temperature. The

MAX

:

MAX

S1

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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 are 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 isolating switch of 6
amp.

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 pump).

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

ensor installation: Temperature sensors may be installed in fluid lines by mounting in a
tee or strapping it to the piping directly. For the system to function correctly, it is essential

that the sensors are located and installed properly. They MUST be pushed completely
into the optional sensor pockets (Thermowell is not supplied). 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 (lasting impedance change).
Exposure to moisture (e.g. condensation) can diffuse through the cast resin and damage the
sensor. In this event, heating at approx. 195 °F for one hour may reverse the damage.

When sensors are used in open loops or swimming pools, corrosion-resistant immersion sleeve,
(sensor pockets), must be used.

l Collector sensor (red cable with protective terminal box): Either push into a thermowell,
(sensor pocket), which is soldered or riveted directly to the manifold (vacuum tubes). Alternately,

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strap the sensor to the collector outlet pipe or the absorber (flat plate collectors) that projects from
the collector housing. Ideally, house the collector sensor (encased in a suitable sensor pocket)
into a T-piece on the collector return outlet. Protect the sensor cable from UV and moistur e.

l Return (tank) sensor (white cable): The sensor required for the solar loop return is installed
in the lower part of the storage tank. If there is no provision for this tank sensor, push the sensor
beneath the insulation – keeping it close to the inner tank wall at the desire tank location.

For external heat exchangers, the tank sensor should be installed with an immersion sleeve in the
return leg (cold side) of the heat exchanger. In tanks with integrated heat exchangers, the sensor
pocket should be fitted at the exchanger's return to the collector.

l Pool sensor installation: Place a heat conductive T-piece on the suction line directly at the
pool outlet and screw in the sensor with an immersion sleeve (check corrosion resistance of the
material used). Alternately, attach the sensor with clips or adhesive tape, using the appropriate
thermal insulation to guard against environmental influences.

l Sensor cable extension: Sensor cables (22/4 AWG telephone cable, you need only two
wires of 4) can be extended up to 150 ft. A connection between the sensor and extension can be
established as follows:

Cut the supplied heat-shrinkable tubing to desired length (about ½ ”). Slide tubing over one end of
wire to be sliced (after removing enough outer insulation to accept the tubing). Splice the wire
and slide tubing over the splice. Heat gently all around until tubing shrinks tight.

Slide larger tubing (about ¾ “) over the entire completed splice. Heat gently all around until tubing
shrinks tight. This connection can then be drawn gently into the pipe work. Only two of the wires
are required for the sensor cable; the other two wires are spare wires.

Caution: Do not overheat the tubing! Remove heat as soon as the tubing shrinks tight, as
material will continue to shrink. With flame source, use even back and forth motion all around
tubing. A heat gun may be used, if available. Let tubing cool for maximum strength.

ontroller unit installation: For viewing comfort, the controller unit should be positioned

at eye level. For optimum longevity, avoid extremes of temperature in the placement of
electronic equipment. In addition, avoid heavy electrical loads, switches or contactors as these
may cause electrical and electromagnetic interference with the unit (when switched on or of f).

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Undo the screw at the top of the housing. The control electronics are mounted on the enclosure
cover. The controller enclosure can be screwed to the wall with cable entry grommets pointed
downwards. Use the supplied plastic bridges to secure power and sensor cables.

Base of the unit to be mounted at eye -level and wired as shown above

Caution: Controller wiring should only be done when the unit is not energized. It is possible to
damage the control unit if it is assembled under voltage. Miniaturized terminal blocks are used for
making wiring connections. The wire is held in place within the terminal with screw that provides
excellent contact without damage to the wire.

Sensor Cable Connection: Use up to an 18 AWG stranded wire to connect the sensor cables to
the unit. The S1 terminal should be connected to the collector sensor (higher temperature); the
S2 terminal is designated for the tank sensor (lower temperature). And the S3 terminal is
reserved for the advanced usage of the unit such as third temperature sensor (in program mode

1) or flow meter input for BTU operation in advanced programming mode.

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P

Y

ower Connections: A small blade screwdriver may be used to fasten miniaturized
terminal block screws while the corresponding wire is inserted.

NOTE 1: Always disconnect the controller from power supply before opening the housing.
NOTE 2: The controller should be properly grounded. Flexible wires, 18/3 AWG

(gauge/conductor) simplify connection to the terminals. The power terminal block will
accommodate wire sizes to 14 AWG. All other connections should be secured and adequately
tightened, as loose power connections will over-heat, and may cause fire.

NOTE 3: It is important that the specified output loads (245 Watts) are not exceeded. Where
these loads expect to exceed, external relays must be used. It is good practice to install a switch
to disconnect the controller and pump from power. Always keep power cables away from sensor
cables and other low voltage signal cables.

NOTE 4: To protect against lightning damage, the system must be grounded according local
regulation. Sensor failures due to the weather or electrostatic are mostly due to poor grounding.

our controller displays requested information one at a time. The unit displ ay window
has three lines to inform you about the system's status, unit of displayed parameter
and its value.

Upper Line Display Symbolic display of sensor location, reading unit, and operation domain
Center Line Display Sensor ID and its reading in normal mode (user interface window)
Lower Line Display Set-point indicator that illuminates only during programming mode

ð Push selection key once to move to the next selection; or increase the selected

parameter by one unit.

ï Push selection key once to move to the previous selection; or decrease the selected

parameter by one unit.

ò Push selection key once to enter the advanced (Par or *Men) mode. Once in selected

mode, press one more time to select the parameter in that mode. Selected parameter
blinks allowing the user to modify it. You can modify the selected parameter while the
middle window blinks by pressing the ï or ð key.

ñ Push selection key once to accept selection (blinking stops showing the new set-point

steady) or go back to the previous selection.

* Menmode is for use in advanced applications only. See P.9.

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Use selection keys ïð during normal system operation to display the desired parameter:

T1 xxx Collector temperature in oF
T2 xxx Tank temperature in oF
T3 xxx Reading of the third sensor; if the third sensor is not used it displays a fixed

reference temperature of 250 oF

XX xxx Collector power in [kW]
YY xxx Energy collected in [MWh]
ZZ xxx Energy collected in [kWh]
GAL xx Flow rate [gallon/h]

Operation Mode – Example: Following chart displays system temperatures

At the upper text line , the icon for the text is always displayed. Program symbol is displayed
during the setting of parameters at the lower text line . In addition, an arrow icon > is displayed
while pump is running.

Program Mode - Pressing the selection key ð several times allows you to enter into the

program mode (Par). Push selection key ò once to enter the program mode.

Basic Operation (Factory Setting for Only Two Sensors)

PROGRAM 0: (basic 2-sensor program)

Par Using the navigation key ^_ allows you to select the desired parameter while you are in

the program mode. Press the selection key ò once to select the parameter in the
window. Selected parameter blinks allowing you to modify it. You can modify the
selected parameter while the middle window blinks by pressing the ï or ð key. The
unit accepts the new value by pressing the ñ key once. To avoid unintentional set -point
changes, the user must enter the access code “32” to manipulate factory settings.

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RUV X.X – This display shows the software revision number.
NR O – This is PROGRAM 0 which indicates simple operation of unit as a Universal Solar
Differential Temperature (USDT) controller. Change this value to 1 (NR 1) for activation of the
third sensor or pulse flow meter input (PROGRAM 1).

Hysteresis Bandwidth

User can program hysteresis (temperature range for output control) by using max ? and max =.

For

max?1 Pump stops above tank temperature (T2)
max=1 Pump runs again below this set point (T2)

Delta T Adjustment

diff=1 Pump runs when temperature difference between collector T1 (collector) and T2

(tank) exceeds this value. Factory setting is 15 oF. Consult your collector
manufacturer for the recommended value.

diff?1 Pump stops when temperature difference between collector T1 (collector) and T2

(tank) reaches this value. Factory setting is 7 oF. Consult your collector
manufacturer for the recommended value.

Manual Operation Mode

AUTO The above display indicates that the unit is working in automatic mode. The

pump starts at a temperature difference of 15 oF and runs as long as ? T is
above 7 oF. The B symbol appears in upper display line next to the collector

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symbol while the pump is running. User can switch to manual mode by pressing
ò key. By pressing ð key while centerline blinks, a hand symbol G in lower line
shows manual operation. Pressing ð one more time lets you turn the pump ON or

OFF. By pressing ñ key you change the pump operation.

Advanced Operation (Setting for Three Sensors and Flow Rate Input)

To change the factory setting of two sensors you need to advance to the Men domain using
access code “64”:

Navigation of advanced features of the unit and selection of parameters is the same as before by
using ïòñð keys:

Advancing – Press the Advance key ïð briefly to advance to the next selection or to
increase/decrease the set point of the selected parameter. Hold it down for fast change.

Acceptance – Press Set-Up key ò once to select the parameter. Press ñ key to accept the
selection or the set point .

Three-Temperature Sensor Setting (PROGRAM 1):

USDT 2004 accepts two different sensor types or a reference value. Press the
Advance key ïð briefly until SENSOR appears in centerline and press the key ò.
Select S3 sensor and change the 250 reference value to read KTY sensor:

Note: Tank over heating protection in program mode 1 (NR 1) controls the pump
operation based on temperature reading by T2 and T3 sensor readings.

Selection:
S3 Sensor 3 (tank) selection

Designation:
KTY Thermistor sensor (2000 O at 25 oC)

Accept this setting by pressing ñ key. If you wish to change set points for pump
operation, follow instruction explained in Basic Operation section (these changes
are made in Par domain).

max?1 Pump stops above tank temperature (T2)
max=1 Pump runs again below this set point (T2)

max?2 Pump stops above tank temperature (T3)

A

max=2 Pump runs again below this set point (T3)

Energy calculation mode (PROGRAM 1):

USDT 2004 computes the energy production as a function of the temperature
differential and fluid volume. In addition, the system anti-freeze (Glycol) percentage
should be entered as it affects the thermal conductivity and heat transfer rate.
Press the Advance key ïð briefly until BTU appears in centerline and press the
key ò. Designate sensor inputs for example T1 as collector inlet and T2 as
collector outlet temperature. F SEN can be connected to a flow meter or be a
constant number in a closed loop solar system.

BTU Energy calculation mode
S IN Sensor port selection for inlet temperature (1, 2, 3, --)
S OUT outlet temperature (1, 2, 3, --)
F SEN Sensor port selection for flow rate (1, 2, 3, --)

Energy calculation will be initiated only after temperature sensor ports are
designated. Flow rate can be either a constant number to be entered by user, or
from a flow meter input. To activate the energy calculation without using the flow
meter's impulse input, a dash (-) must be selected for F SEN channel followed by
the constant flow rate in gph (gallon per hour) unit.

LLP Flow met er rate impulse number in liter per pulse, if flow meter is

used

GAL Constant flow rate in gph instead of flow meter reading in (--)

sensor mode

GLYCOL Anti-freeze percentage
CLEAR Sets the BTU meter's counter to zero
DIF Sensor calibration

The output of USDT 2004 unit is kW for system power and kWh or MWh for
collected energy.

dvanced Mode – USDT 2004 is extremely powerful. It can be used in wide range of applications

such as a BTU meter, a boiler fuel optimizer, a swimming pool temperature differential

controller, a greenhouse temperature regulator, an air handler, and more. Factory
settings are exclusively for solar water heating systems in the USA market. However, all its
parameters can be changed to meet the unique requirements of other applications. The user may
use access code "64" to modify the USDT 2004 program mode and its parameters.

Men This mode is for advanced applications

The factory setting will be retrieved by pressing and holding ò key during powering of the
unit. A “RESTOR” displays for three seconds while factory settings are restored.

Selection of different sensor types, energy collection calculation parameters, system protection
and optimization can be can be modified in advanced (Men Domain ) mode.

Mode Operation
SENSOR Selects sensor type

SGUARD Protects system from overheating and frost

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F

START Starts pump at pre-set insolation (solar radiation intensity)
ALARM Enables/Disables protection functions
BTU Energy calculation and setting

ensor Designation – USDT 2004 accepts two different sensor types or a reference

value . User can program a constant reference temperature instead of a sensor output.

The factory-preset sensor is the thermistor (KTY 10) type. The KTY 10 tank sensor,
white wire, should be used in a conditioned environment and will not be permanently damaged up
to 360 oF.

Selection:
S1 Sensor 1 (collector outlet) selection

S2 Sensor 2 (collector inlet) selection
S3 Sensor 3 (tank) selection

Designation:
PT PT 1000 sensor (1000 O at 0 oC, not available in US market)

KTY Thermistor sensor (2000 O at 25 oC)
250 250 oF reference temperature

- 4 - 4 oF reference temperature

Sensor wires can receive electromagnetic pulses, which can result in a wrong temperature
reading. The USDT 2004 reads sensor values every 50 ms. It can bundle several readings and
process their average.

AV 1 Sensor 1 average
AV 2 Sensor 2 average
AV 3 Sensor 3 average

The numbers of samples can be programmed from 4 to 20. The impedance characteristics of
sensors temperature dependencies are represented in the following table:

T 0 10 20 25 30 40 50 60 70 80 90 100°C
R(KTY) 1630 1772 1922 2000 2080 2245 2417 2597 2785 2980 3182

rost and overheating protections - Pump operation can be manipulated by the user in

both collector stagnation and frost conditions. The set-up is possible in System Guard,

SGUARD, domain.

Overheating protection – The Circulation pump may not be powerful enough to circulate the

heat transfer fluid in the solar loop with air pockets. User can program the pump to stop at a
desired maximum collector temperature, shown by ? symbol, to protect the pump. The USDT
2004 will take over the normal operation after the temperature decreases to an acceptable
working temperature, shown as =. This feature is disabled at 299 oF set point.

Frost Protection – Frost protection in the sun -belt region is provided by circulating water in the
solar loop when freezing conditions exist. Regardless of the temperature difference ? T, the

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circulation pump runs when the collector temperature is below a programmable minimum
temperature, shown by = symbol. The pump stops as soon as the temperature in the solar loop
reaches a safe region programmed by the ? symbol. This feature is also disabled at the factory
by entering - 4 oF.

min= Pump runs below this temperature
min? Pump stops above this temperature

tart functions - The Circulation pump can be programmed to start on low insolation

level. The Start function feature is useful when heat transferred to the collector sensor is

not fast enough for early start; especially when the collectors are flat mounted.
The enabled start function runs the pump at a given solar radiation or programmed temperature

difference. The feature is disabled at the factory.

START Start function screen
ENABL Enable start function
DISAB Disable start function

If this feature is selected, following parameters must be adjusted for proper operation:
SENS Pyranometer port designation (radiation monitoring sensor port)

1 Sensor 1
2 Sensor 2
3 Sensor 3

-- Manual input in next step

INS Radiation threshold in W/m2
CIRC Pump runtime in seconds
INT Maximum interval time in second
FLU Number of flushes

The following example activates the circulation pump at 200 W/m2 and runs it for 15 seconds. If
rT condition is met within the time period, the pump stays on.

INS 20
CIRC 15

larm functions - User can enable the alarm function of the USDT 2004 in the ALARM
screen. Status of sensors and circulation pump can be viewed if alarm function is active.

A ON Alarm function enable
A OFF Alarm function disable

The status of the system can be monitored in the Stat Mode only if the corresponding feature is
active. The following example shows a system condition with a circulation problem:

OT OFF Overheating feature disable
OT OK No overheating
1 SHORT Short circuit in sensor 1 wiring
2 SHORT Short circuit in sensor 2 wiring
1 OPEN Disconnection in sensor 1 wiring

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2 OPEN Disconnection in sensor 2 wiring
OK System operates normal
NO CIRC r T is more than 108 oF in last 30 minutes
OK CIRC Pump is running
CLEAR Clears NO CIRC display after correction

nergy calculation - Energy gain is calculated by obtaining the temperature increase of

heat transfer fluid across the solar collector. The amount of fluid flow through the
collector is registered by an in -line flow meter. USDT 2004 computes the energy production as a
function of the temperature differential and fluid volume. In addition, the system anti-freeze
(Glycol) percentage should be entered as it affects the thermal conductivity and heat transfer
rate.

BTU Energy calculation mode
S IN Sensor port selection for inlet temperature (1, 2, 3, --)
S OUT outlet temperature (1, 2, 3, --)
F SEN Sensor port selection for flow rate (1, 2, 3, --)

Energy calculation will be initiated only after temperature sensor ports are designated. Flow rate
can be either a constant number to be entered by user, or from a flow meter input. To activate the
energy calculation without using the flow meter's impulse input, a dash (-) must be selected for F
SEN channel followed by the constant flow rate in gph (gallon per hour) unit.

LLP Flow meter rate impulse number in liter per pulse, if flow meter is used
GAL Constant flow rate in gph instead of flow meter reading in (--) sensor mode
GLYCOL Anti-freeze percentage
CLEAR Sets the BTU meter's counter to zero
DIF Sensor calibration

The output of USDT 2004 unit is kW for system power and kWh or MWh for collected energy.
The energy calculation dependents on flow meter accuracy, the temperature sensors class, and

their locations. The flow meter is a mechanical device and its accuracy fluctuates over time.
Therefore, the user should calibrate the flow meter and incorporate temperature sensor tolerance.

The supplied Thermistor sensor has an accuracy of ± 2 oF. DIF represents the temperature
difference between two sensors. User can increase the accuracy of reading by adjusting the DIF
parameter. The energy calculation becomes accurate at temperature range that this reading
adjustment is made.

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In general, all of the settings in the menus Par and Men and the terminal should first be checked
if there is a malfunction.

Malfunction, but "realistic" temperature values:

Incorrect display of temperature(s):

The sensor can also be checked without a measuring instrument by connecting the presumed
defective sensor to a terminal that works and checking the display. The resistance measured by
an ohmmeter should have the following value depending on the temperature:

T 0 10 20 25 30 40 50 60 70 80 90 100°C
R(KTY) 1630 1772 1922 2000 2080 2245 2417 2597 2785 2980 3182

roubleshooting

• Check program number.

• Check the switch-on and switch-off thresholds and the set differential temperatures. Have

the thermostat and differential thresholds already been reached?

• Were the settings in the submenus (Men) changed?

• Can the pump (output) be switched on and off in manual mode? If a forced pump “ON”

and “OFF” lead to the appropriate reaction at the output, the unit is certainly in order.

• Are all of the sensors connected with the right terminals? Heat up the sensor using a
cigarette lighter and watch the display.

• Did you change the reference temperature 250 (three sensor operation) to KTY?

• Displayed values such as -999 if a sensor short -circuits

• or 999 if there is an interruption do not necessarily mean a material or terminal error.

• Are the right sensor types (KTY or PT1000) selected in the menu Men under SENSOR?

The factory settings set all inputs to KTY.

3392 Ω

The settings of the parameters and menu functions ex works can be restored any time by
pressing the down arrow (enter) while powering the controller. The sign that appears for three
seconds on the display is RESTOR for load factory settings.

If the system is not in operation while connected to the power supply, the 3.15A quick-blowing
fuse that protects the control system and the output should be checked and exchanged if
necessary.

As the programs are constantly being improved, there may be a difference in the sensor, pumps,
and program descriptions. Only the enclosed manual (identical serial number) applies for the
equipment supplied. The program version for the manual must correspond to the equipment
version.

If the control system is found to be malfunctioning despite the checks described above, please
contact your retailer or Thermo Technologies directly. The cause of the error can only be
determined if the settings of the unit is known. The schematic diagram of the system in question
is a great help to isolate the potential problem.

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