AZEL DST-932 User Manual

70 mm

90

SET

33

UP

DOWN

6.00 PARAMETER LIST

FACTORY

dt Delta T Set Point

Range

(dtd) 0.8 .. 50.1 °F

15 °F

dtd Delta T hysteresis

Range 0.8 .. 17.9

(dt) °F 2 °F

Offset 1, temperature calibration for

Offset 2, temperature calibration for

AcY Anticycling time relay

Range 0 ..

254 seconds

3 s

Range 0.3 .. 50.0 °F;

Range 32.1 .. 228 °F;

AdF Anti Freeze hysteresis

Range 0.8 .. 17.9 °F

5 °F

0: Cels

ius;

0: decimal point resolution;

utd Display update time delay

Range 0 .. 60 sec

1 sec

0: NTC (10Kohm thermistor;

7.00

ANOMALIE

S SIGNALING

MSG CAUSE OUTPUT

The temperature of probe 1 (storage water

The probe input line 1 is open or short circuited.

The probe input line 2 is open or short circuited.

8.00 SPECIFICATIONS

1.00 GENERAL DESCRIPTION AND INSTALLATION NOTICE

Up: 1) To increase the value of the selected parameter;

2)

To

FRONTAL PANEL LAYOUT AND FUNCTIONS

Typical terminal connections

(See the label close to the terminals

Azel Technologies Inc.

AC

Line

115V

DST-932

N

# MEANING SETTING

SETTING

OFS

probe on the storage tank

OF2

probe on the collector

AF Anti Freeze protection

OP Over Temperature protection

Opd Over Temperature hysteresis Range 0.8 .. 17.9 °F 5 °F

unt Temperature displayed unit

rES Resolution

Range –8.4 .. +7.6 °F 0 °F

Range –8.4 .. +7.6 °F 0 °F

OFF: the protection is disabled.

OFF: the protection is disabled.

1: Fahrenheit

1: unit resolution

Pt Sensor Probe Type

range –40..+248°F)
1: PTC (1Kohm thermistor;
range –58..+302°F)

- ONLY IN AUTOMATIC MODE -

HIt

tank) is higher than the OP value (over­temperature) .

PF1

The storage tank measured temperature is out
of range.

PF2

The collector measured temperature is out of
range.

- output K1 will switch-off.

- output K1 will switch-off.

- output K1 will switch-off.

Azel Technologies Inc. reserves the right to make changes wit hout further notice to an y

products herein to improve reliability, function or design. Azel Technologies Inc. does not
assume any responsibility for any improper use or application of any product or cir cuit described
herein. Azel T echnologies Inc. products are not designed, intended, or authorized to be use as
components in systems or applications intended to support or sustain life, or f or any other
application in which t he f ailure of th e Azel Technologies Inc. product could create a situation
where personal injury or death may occur.

oFF

159 °F

1

1

0

DISPLAY: 3 digit, 13.2 mm, high intensity green;

INPUTS: two NTC sensors or two PTC sensors;

MEASURING RANGE: -55 … +302 °F for PTC probe;

ACCURACY AT 25°C: ±1 °F + 1 digit;

RESOLUTION: 0.2 or 2 °F;

OUTPUTS: 1 spdt 250Vac 16A max resistive (1hp);

POWER SUPPLY: 115 Vac ±10% 50/60Hz;

ENVIRONMENTAL CONDITIONS:

- operating temperature: –5 … +50 °C;

- storage temperature: –20 … +70 °C;

- relative humidity: 30 … 90 % non condensing;

- no shocks or vibrations;

MECHANICAL DATA:

- plastic housing self extinguishing type UL94V0;

- connections through terminal block for 2.5mm2 gauge wire;

- protection degree: IP64 for the frontal panel (enclosure IP31).

for the right power supply diagram connection).

-39 … +248 °F for NTC probe;

16(8)A 250Vac

K1

WATER

PUMP

L

115VAC

PO BOX 53138

10 Royal Orchard Blvd.

THORNHILL, ONTARIO

CANADA L3T 7R9

Ph: 905-223-5567

Fax: [phone]

web: www.azeltec.com

e-mail: [e-mail]

Installation and

operating instructions

45

Led 1Led 2

SET

DST-932

Differential Temperature Control

for

Solar Heating System

Rev.: 11-10-2005 Cod.: 00990270

The DST-932 model i s conceived to control the Solar Heating Systems. The DST-932 drives a pump in order to warm u p the water into a
storage tank (by the sun energy). The controller reads the temperatures of the storage tank (T1) and of the collector (T2), when this differential
temperature (T2-T1) is h igher than a set value (dt) it will switch on the water pump. It is possible limit the maximum temperature of the storage
tank and also activate a freeze protection function. By switching to manual mode it allows the test of the heating system.
The controller must be installed in a place protected from extreme vibration, impact, water, corrosive gases, and where temperatures and
moisture do not exceed the maximum rating levels indicated in the specifications. The same directions are valid for the probe installation.

1.10 THE THERMOSTAT PROBEs

The probes must be installed in a place to measure the correct average temperature of the system. The probe is not waterproof, it should be
placed with its head upward, so that drops would not penetrate into the bulb and damage the sensor. Maintain the length of the electrical wires
as short as possible in order to keep the noise picked by them at low level, otherwise a shielded wire will be needed, where the shield will be
connected to the ground. If moisture goes into the probe bulb, it false the reading temperature and the control action.

1.20 ELECTRICAL WIRING

We recommend to protect the power supply of the controller from electrical noise, spikes, and especially from voltage surges and drops. This
can be easily done following these recommendations:

-separate the power supply of the loads (boilers, heaters, fans, etc) from the power supply of the controller. This can alleviate problems
related to voltage dips that can arise during the switch-on of the loads, that may interfere with the controller’s microprocessor causing
unexpected resets.

-the cables of the probes and the ones of the controller supply or the loads must be separated and not close, to reduce spikes and noise on the
sensor. This improves the stability of the reading and it also makes the commutation of the device more accurate.

1.30 CRITICAL ENVIRONMENT

For applications in heavy industrial environment these rules should be followed.

- After having identified the source of noise spikes, it is recommended to apply a line filter to the source in question of the type specifically
designed to solve EMC (Electromagnetic compatibility) related problems. Sometimes it may be sufficient an RC type filter, also called
«snubber» , connected in parallel to the external relay coils, or circuit breakers.

- An independent power supply should be used to power the device in extreme conditions.

1.40 MOUNTING

The controller is a DIN rail mounting instrument which can be mounted onto the wall or panels. For easily mounting, remove the DIN rail by
sliding it out first. Use screws to mount the DIN rail onto the wall/panel. Then snap on the control to the DIN rail by pulling black trigger on the
bottom with a screw driver.

scroll the parameters in SET mode; 3) To show the collector
temperature (probe 2).

Down: 1) To decrease the value of the selected parameter; 2)
To scroll the parameters in SET mode.

Set: To access the parameter menu to view and change the
values. It is also the “Enter” key to confirm the new values.

Mode: Used to switch the automatic/manual mode.

MODE

OP –

over temperature protection:

it is the maximum

2.00 HOW THE DEVICE WORKS (overview)

4.10 HOW TO ADJUST THE OPERATING PARAMETERS

2.20 FAULT TOLERANCE

5.0 GENERAL PARAMETERS DESCRIPTION

Automatic

m

anual on

manual

oFF

Store tank

Probes fault

Collector

T2 –

T1 >

Solar Panel

Storage tank

The DST-932 is a differential temperature controller. In automatic mode it drives the relay output checking the difference of the temperatures from
the collector T2 and the storage tank T1. In order t o store the solar energy, it switches on a circulator pump as soon as T2-T1 is greater than a
Delta T set point (dt). Also, there are over temperature and freeze alarm.
To verify the whole heating system it is possible toggle to manual mode and switching on or off the circulator pump. In manual mode the controller
does not read any probe value, so no alarm function is activate.

2.10 AUTOMATIC MODE CONTROL

The controller check every conditions in the following matter:

collector

T2

PF1 or PF2

Yes Yes Yes Yes

temperature

T1 > OP

circulator

pump

No No

temperature

T2 < AF

water

T1

No No

dt

Pump OFF

Pump ON Pump OFF Pump OFF Pump ON

In case of probe failure the DST-932 controller display a message PF1 or PF2 and it switches off the output K1 (as per table 7.00) .

3.00 DISPLAY FUNCTIONS

The display has three digits available, of the seven segment type.
During Automatic mode working it shows the value of the storage tank probe temperature T1. Pushing the upper button, it shows for 3 seconds the
collector probe temperature T2. In an over-temperature alarm condition it blinks the “Hit” message (as described in the «anomalies signalling»
table 7.00).
In manual mode the display shows the current selected mode: on or off. No one alarm or temperature is checked and showed.
The leds have the following functions: LED 1 lights on when the output K1 (water p ump) is a ctivated. The led 2 blinks during the setting
operations.

4.00 HOW TO DISPLAY AND ADJUST THE “DELTA T” SET POINT

Note: The internal mathematic calculation of the thermostat works in °C. When adjusting the temperature with temperature display unit set as °F,

it may increment/decrement by 2°F instead of 1°F. This is for conversion rounding off purpose, so not all the values of °F will be represented" ­EXAMPLE: SET= 73, 75, 77, 78, 80, 82… (For rES = 1). If more accuracy is desired, decimal point resolution (rES=0) can be set. Then all the
values of °F will be displayed and the increment/decrement is changed by 0.1/0.2 °F.

1) Press “SET” and hold it for 3s, “dt” is displayed;

2) Press “SET” to view the dt Set Point value, adjust it by using “5” or “6”;

3) Press “SET” to confirm the data, after few seconds the controller will leave the set mode and the data will be stored in the memory.
WARNING: the instrument must not be reset before leaving the set mode, otherwise the new setting will be lost.

(only in Automatic mode)

1) Press “SET” and hold it for 10s, the code of the first variable “dtd” will appear;

2) Press “5” or “6” to scroll all the parameter codes;

3) While a code is displayed press “SET” to view its content, adjust it by pressing “5” or “6”;

4) Press “SET” to confirm the data, after 10s the controller will leave the set mode and the data will be stored in the memory.

WARNING: the instrument must not be reset before leaving the set mode, otherwise the new setting will be lost.
Note: In every case the controller automatically interrupts any setting operation if any push-button isn’t pressed for at least 10 seconds.

The new values for time parameters will be active only after the start of the following time cycle.

4.20 HOW TO TOGGLE MANUAL-AUTOMATIC MODE

Press and hold for 5s the “MODE” key, the DST-932 will toggle among the following modes:

In automatic mode the controller shows the storage tank temperature and it controls the water pump as indicated on 2.10.
In manual mode the controller switches on (or off) the relay output and it shows “on” (or “oFF”) on the display. It is suitable to test the solar heating
system. No error-detection-routines are activated (no probe faults, no over temperature, no anti freeze).

After every power down condition, the controller starts up in autom atic mode.

4.30 HOW TO SHOWS THE COLLECTOR TEMPERATURE PROBE 2

Press “5”, the display will show the collector temperature for 3 seconds, then it come back to show the storage tank temperature T1.

4.40 KEYBOARD LOCKING

Press and hold “6” + “SET” for 10s, in order to lock and unlock the keyboard

(pay attention to do not modify the dt set point value, press first “6” and then “SET” immediately and keep pressed for 10 seconds).

Code displayed for one second: “Pof” – keyboard locked; “Pon” – keyboard unlocked.
When the keyboard is locked it is not possible change any parameters value (apart from the dt Set Point).

dt – Delta T Set Point: it’s the minimum differential temperature,

between the collector and the storage tank, to switch on the water
pump (relay K1). The controller switch on the output K1 when T2-T1>dt.

dtd – Delta T hysteresis: the value that controls the output relay K1,
moving the value of the dt set point in such a way that the system does
not oscillate.
The controller switch off the output K1 when T2-T1<dt-dtd.

OFS – temperature offset for storage tank: it is the variation
temperature added or subtracted to the temperature measured by the
storage tank probe to compensate for any deviation from the real value.

OF2 – temperature offset for collector: it is the variation temperature
added or subtracted to the temperature measured by the collector
probe to compensate for any deviation from the real value.

AcY – main anticycling delay time: it is the minimum time between
two successive output maneuvers (off – on cycle) for the relay K1: when
the water pump is switched-off, the controller wait at least “AcY”
seconds to switch on it again. It is also the delay for the first activation
of the relay K1 at the start-up.

AF – anti freeze protection: it is the collector temperature T2 below it
the controller will switch on the pump. Regardless of the temperature
difference T2-T1, when T2<AF the circulation pump runs providing frost
protection.

relay energized as per Delta T

(only in automatic mode)

relay manually activated

(only in Automatic mode)

temperature T1 of the storage tank, above it the controller will
active the over heat alarm protection, switching off the pump and
blinking “HIt” on the display. Regardless of the temperature
difference T2-T1, when T1>OP the circulation pump stops. This
function is prioritary to the other functions.

OPd – over temperature hysteresis: the value that controls the
ending of the over temperature alarm protection: when T1<OP­OPd the controller can switch on the output again, as per T2-T1
value.

AdF – over temperature hysteresis: the value that controls the
ending of the anti freeze protection: when T2>AF+AdF the
controller stops the pump and it can drive the output again as
per T2-T1 value.

unt - displayed unit: it switches the temperature unit between
Celsius and Fahrenheit (internal calculations are made in
Celsius and then converted to Fahrenheit - see point 4.00 note).

rES – resolution: it allows to display the measured value with
decimal or unitary resolution.

utd – update Time delay: it is the time delay that determines
the display updating of the temperature (the min update time of
the display is 5 sec.). The switching over of the relay is related
only to the acy not to utd values.

Pt – Sensor probe type: choice of either 10K ohm NTC sensor
or 1K ohm PTC sensor.

relay manually in off position

(only in automatic mode)