EPH Controls CDT2-24 User manual

CAUTION!
Before commencing any work on the electrical
connections, you must rst disconnect the thermostat
from the mains. None of the 24V connections must be live
until the installation has been completed and the housing
is closed. Only qualied electricians or authorised service
sta are permitted to open the thermostat.
There are parts that may carry mains voltage behind the
cover. The thermostat must not be left unsupervised
when open. (Prevent non specialists and especially
children from gaining access to it.)
Operating Instructions
Page 1 of 3
CDT2-24 Room Thermostat with Delay Start
Contents
1. Factory default settings
2. Specication & wiring
3. Mounting
4. Installation
5. Wiring diagram
6. Frost protection
7. Button / symbol description
8. Resetting the thermostat
9. Keypad lock and unlock
10. High and Low temperature limitation
11. Adjusting the switching dierential
12. Adjusting the setpoint temperature
13. Changing the thermostat mode
14. Normal control mode (On / O)
15. Delay start control mode
16. Time Proportional Integral Mode (TPI)
4. Installation
1. Factory default settings
8. Resetting the thermostat
7. Button / Symbol description
6. Frost protection
9. Keypad lock and unlock
2. Specications & wiring
Contacts: Volt Free
Temperature indicator: °C
Switching dierential: 0.4°C
In built frost protection: 5°C
High and Low temp. limitation: O
Blue backlight activated : for 10 secs after any button is pressed
Keypad lock: O
5°C
OFF
Reset button
Set point increase
Set point decrease
Set button
On / Standby button
Room temperature
Heating ON symbol
3. Mounting
Prior to setting the thermostat, it is neccessary to
complete all required settings described in this section.
5. Wiring diagram
Important: Keep this document
Power supply: 24Vac 50Hz
Power consumption: 8 VA
Temp. control range: 5 ... 35°C
Ambient temperature: 0 ... 50°C
Contact rating: 7A 24Vac
Dimensions: 84 x 84 x 30mm
Temperature sensor: NTC 10K Ohm @ 25°C
Switching dierential: Adjustable from 0.2/0.4/0.6/0.8/1.0˚C
Frost protection: Only operational in stand by mode
Slacken the fastening screw on the bottom of the thermostat with a philips
head screwdriver.
The thermostat is hinged and can be opened 180 degrees.
Mount the unit as described in section 3.
Wire the thermostat according to the wiring diagram.
Close the thermostat and tighten the fastening screw.
The mounting height should be 1.5 meters above the oor level.
The thermostat should be wall mounted in the room where the heating is to
be controlled.
The place of installation should be chosen so that the sensor can measure the
room temperature as accurately as possible.
Choose the mounting location to prevent direct exposure to sunlight or other
heating / cooling sources when mounted.
The unit can be tted to: 1. Recessed conduit boxes
2. Surface mounting boxes
3. Directly on walls.
If 24Vac output is required, terminals L & 2 must be electrically linked.
INTERNAL WIRING DIAGRAM CDT2-24 321LN
24Vac
SUPPLY
ON OFFCOM
Frost protection is built into this thermostat, it is pre xed at 5°C and is not
adjustable.
It will only be activated when the thermostat is in the stand by mode and
the room temperature reaches 5°C.
It is necessary to reset the thermostat prior to initial use.
Press and hold the button for 5 seconds.
dEL will appear on the screen.
Press the button on the side of the thermostat.
RESET
Set
To lock the keypad, press and hold the and buttons for 5 seconds.
will appear on the screen. The keypad is now locked.
To unlock the keypad, press and hold the and buttons for 5 seconds.
will disappear from the screen. The keypad is now unlocked.
20221006_CDT2-24-DS_Opins_PK
EPH Controls Ireland
[e-mail] www.ephcontrols.com
EPH Controls UK
[e-mail] www.ephcontrols.co.uk

CDT2-24 Room Thermostat with Delay Start
14. Normal control mode (On/O )
15. Delay start control mode
When the temperature falls below the setpoint temperature, the ame
symbol will appear and the thermostat will switch on.
When the temperature rises above the setpoint temperature, the ame
symbol will disappear and the thermostat will switch o.
22˚C
21˚C
20˚C
19˚C
18˚C
17˚C
Temp
Time Minutes
Graph (14.1): On / O Control
Setpoint Temperature
200 40 60 80 100
Delay start is an energy saving mode.
When the delay start function is active the ame symbol will continuously
ash on the screen. When in this mode the activation of the thermostat is
delayed by a variable time depending on the current temperature, setpoint
temperature and also the fall in temperature from when the delay start has
activated. See graph (15.1) Delay Start Control.
The ame symbol will continue to ash until the thermostat activates.
When activated the thermostat will allow the heating system time to reach
the setpoint and delay start will remain inactive until it reaches this setpoint.
Delay start can be reactivated by:
Lowering the setpoint below the current temperature, pressing the
‘standby’ button to set the temperature, then raising the setpoint above the
zone temperature within 6˚C of the setpoint.
The heating will be delayed as per the line on the graph.
If the dierence between the actual temperature and the setpoint is 1C the
thermostat will delay starting for circa 40 minutes.
If the dierence between the actual temperature and the setpoint is 3C the
thermostat will delay starting for circa 24 minutes.
If the dierence is 6C or more, the heating will be switched on immediately.
The time delay will change if the temperature drops from the original
calculation.
To deactivate Delay Start, see section 13.
48.0
42.0
36.0
30.0
24.0
18.0
12.0
6.0
0.0
0123456
Temperature below thermostat setting °C
Time delay after Delay Start activated in minutes
Graph (15.1): Delay Start Control
10. High and Low temperature limitation OFF
Set
Set
11. Adjusting the switching dierential (Normal)
12. Adjusting the setpoint temperature
Press the button once, Di set will appear on the screen.
The factory default switching dierential of 0.4C will appear on the screen.
Press the and buttons to select the desired dierential from 0.2 - 1˚C.
Press the button to return to normal operation.
Set
Set
An upper and lower temperature limit may be chosen.
Press and hold the and buttons for 10 seconds.
“Limit OFF”will appear on the screen.
Press the button to select“Limit ON”mode.
Press the button to conrm you wish to adjust the high limit temperature.
Press the and buttons to select the high limit temperature.
Press the button to select the low limit temperature mode.
Press the and buttons to select the low limit temperature.
Press the button and the thermostat is ready for operation.
“Limit” will appear on the screen.
To deactivate High and Low temperature limitation.
Press and hold the and buttons for 10 seconds.
“Limit ON”will appear on the screen.
Press the button to deactivate this function.
“Limit OFF”will appear on the screen.
Press the button and the thermostat is ready for operation.
Set
Set
Set
Set
Operating Instructions
Page 2 of 3
P1- Normal On/O mode
P2- Delay Start mode (DS)
P3- Time Proportional Integral Mode (TPI)
Press the‘Reset’ button at the side of the thermostat.
P1 will appear on the screen.
Use the or buttons to change between P1 to P2and P3.
Select P1 for normal operation.
Select P2 for delay start.
Select P3 for TPI – If P3 is selected you can press the button to choose
the amount of cycles and then press the button to choose the
proportional bandwidth.
Press the ‘standby’ button to conrm.
See section 16 for more information on TPI.
Set
Set
Press the or buttons to adjust the temperature setpoint.
13. Changing the thermostat mode
20221006_CDT2-24-DS_Opins_PK
EPH Controls Ireland
[e-mail] www.ephcontrols.com
EPH Controls UK
[e-mail] www.ephcontrols.co.uk

CDT2-24 Room Thermostat with Delay Start
16. Time Proportional Integral Mode (TPI)
Example – Program 1 on the thermostat is 21°C for 06:30am and the room temperature is
18°C. The thermostat will start the heating at 06:30am and the heat will start to increase
then but will switch itself o before it reaches temperature and allow the room temperature
to increase naturally – this cycle may begin again if the thermostat isn’t reaching
temperature.
22˚C
21˚C
20˚C
19˚C
18˚C
17˚C
Temp
Time Minutes
Heating On Heating O
Setpoint Temperature
Proportional Bandwidth
200 40 60 80 100
TPI Control
There are 2 settings that will aect the thermostats operation:
1. The Number of Heating Cycles Per Hour
2. The Proportional Bandwidth
CyC - Number of Heating Cycles per Hour:
This value will decide how often the thermostat will cycle the heating on
and o when trying to achieve the setpoint temperature. You can select
2/3/6 or 12.
Pb - Proportional Bandwidth:
This value refers to the temperature below the setpoint at which the
thermostat will start to operate in TPI Control. You can set this temperature
from 1.5˚C to 3.0˚C in 0.1˚C increments.
When the thermostat is in TPI mode and the temperature is rising in the
zone and falls into the Proportional Bandwidth section, TPI will start to
aect the thermostats operation. The thermostat will turn on and o as it
gains heat so that it doesn’t overshoot the setpoint by too much. It will also
turn on if the temperature is falling so it doesn’t undershoot the setpoint
which will leave the user with a more comfortable level of heat.
6 Cycles
2˚C
Operating Instructions
Page 2 of 3
20221006_CDT2-24-DS_Opins_PK
EPH Controls Ireland
[e-mail] www.ephcontrols.com
EPH Controls UK
[e-mail] www.ephcontrols.co.uk