EPH Controls HDT Operating instructions

Installation and Operation Guide
Room Thermostat
HDT

2
Factory default settings
3
Specications
4
LCD Display
5
Buttons
6
Wiring
7
Mounting & installation
12
Locking the Keypad / Backlight
13
Menu Function
17
11
On / O Function & Adjusting the setpoint temperature
14
Table of contents
15
13
Delay Start Control (On/O)
PO 1 Operating Mode
Nor (Normal Mode)
Time Proportional Integral Mode (TPI)

22
24
20
21
19
23
PO 2 Setting High and Low limits
PO 3 Hysteresis HOn and HO
PO 4 Calibration
PO 5 Setback Mode
PO 6 Frost Protection
Resetting the Thermostat

Mains operated non-programmable Room Thermostat
Installation Instructions

3
EPH Controls Ltd.
Factory default settings
Contacts: Volt Free
High and Low Temp. limitation: O
Keypad lock: O
Backlight: Auto
Setback: 0.0˚C (o)
Operating mode: Normal

4HDT
Specications
Power supply / Input: 230Vac 50-60Hz
Power consumption: 7mA / 1 Watt
Temperature range: 5 … 35˚C
Ambient temperature: 0 … 45˚C
Ambient admissible humidity: 5-95%RH
Contact rating: 7A 230Vac
Dimensions: 85 x 85 x 36mm
Temperature sensor: NTC 100K
Backlight: White
IP rating: IP20
Pollution degree: 2
Switching dierential: Adjustable from 0.0 – 1.0°C
0.1°C increments
Automatic action: 1A

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EPH Controls Ltd.
[1]
[6]
[2]
[3][4]
[5]
[1] Shows the current / target temperature.
[2] If the keypad is locked, the lock symbol is
displayed.
[3] When the thermostat is calling for heat, the ame
symbol is displayed.
[4] When a high or low temperature limit is set, ‘LIM’
is displayed.
[5] Displayed when setback is enabled.
[6] Displayed when delay start is enabled.
LCD Display

6HDT
Buttons
Handwheel Reset
Button
Standby Button

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EPH Controls Ltd.
Wiring
SB
ON
321LN
L
MAINS SUPPLY
N
COM
230V on Terminal 1: Thermostat works in Normal mode
0V on Terminal 1: Thermostat works in Setback mode
* If mains output is required terminals L and 2 must be electrically linked.
Terminal Connections
LLive In
NNeutral In
Terminal 1 Setback
Terminal 2 Common
Terminal 3 On

8HDT
Mounting & Installation
Caution!
Installation and connection should only be carried out by a qualied person.
Only qualied electricians or authorised service sta are permitted to open the
thermostat.
If the thermostat is used in a way not specied by the manufacturer, its safety may be
impaired.
Prior to setting the thermostat, it is necessary to complete all required settings
described in this section.
Before commencing installation, the thermostat must be rst disconnected from the
mains.
This thermostat can be mounted in the following ways:
1) Directly mounted on wall
2) To a recessed conduit box

9
EPH Controls Ltd.
1) Remove the thermostat from its packaging.
2) Choose a mounting location so that the thermostat can measure
the room temperature as accurately as possible.
- Mount the thermostat 1.5 metres above the oor level.
- Prevent direct exposure to sunlight or other heating / cooling
sources.
3) Use a philips screwdriver to loosen the screw on the bottom of the
thermostat to open the front housing.
4) Screw the backplate onto a back box or directly to the surface.
5) Wire the thermostat according to the wiring diagram on page 6.
6) Close the front housing and tighten the screw on the bottom of
the thermostat.

10 HDT
85
85
26
36
45 113

Mains operated non-programmable Room Thermostat
Operating Instructions

12 HDT
Press to turn the thermostat On or O.
When in the ON mode the thermostat will display the current ambient
temperature.
When in the OFF mode the thermostat will display the current ambient
temperature and the word ‘OFF’.
Rotate clockwise to increase the target temperature.
Press or wait 5 seconds. The target temperature is now saved.
Rotate anti-clockwise to decrease the target temperature.
Press or wait 5 seconds. The target temperature is now saved.
On / O Function
Adjusting the setpoint temperature

13
EPH Controls Ltd.
Locking the Keypad
To lock the thermostat, press for 10 seconds.
will appear on the screen. The buttons are now disabled.
To unlock the thermostat, press for 10 seconds.
will disappear from the screen. The buttons are now enabled.
There are three settings for selection.
‘bL AUtO’ The backlight is on for 10 seconds when any button is pressed.
‘bL On’ The backlight is permanently on.
‘bL OFF’ The backlight is permanently o.
Rotate to change the mode between AUTO, ON and OFF.
Press to conrm selection and to return to normal operation.
Backlight AUTO
To adjust the backlight setting, press for 10 seconds.
‘bL AUtO’ appears on the screen.

14 HDT
Menu Function
This menu allows the user to adjust additional functions.
There are three settings for selection, Normal, Delay Start or TPI mode.
The default setting is Normal.
Press and hold the and together for 5 seconds,
P01 & Nor will appear on the screen,
Press to select.
Rotate to select between
Nor (Normal mode)
dS (delay start mode)
tPi (Time proportional integral mode)
Press to conrm the mode.
PO 1 Operating Mode (Normal / Delay Start / TPI)

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EPH Controls Ltd.
Nor (Normal Mode)
When the temperature falls below the setpoint temperature, will
appear and the thermostat will activate the demand for heat.
When the temperature rises above the setpoint temperature, will
disappear, and the thermostat will cancel the demand for heat.
PO 1 Operating Mode (Normal / Delay Start / TPI)
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

16 HDT
PO 1 Operating Mode (Normal / Delay Start / TPI)
Delay Start Control (On/O)
When the delay start mode is active, ‘dS’ will appear continuously on the
screen. When in this mode 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.
The will ash until the thermostat activates.
E.g: If the temperature is
6˚C below the thermostat
setpoint, the thermostat will
call for heat immediately.
If the temperature is 2˚C
below the setpoint, the
thermostat will not call for
heat for 32 minutes.
48
42
36
30
24
18
12
6
0
0123456
Temperature below thermostat setting °C
Time delay after Delay Start activated in minutes
Graph (15.1): Delay Start Control

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EPH Controls Ltd.
Delay start can be reactivated by:
1. Lower the setpoint below the current temperature.
2. Press to set the temperature.
3. Increase the setpoint above the zone temperature within 6° .
4. Press to conrm.
The heating will be delayed as per the graph on page 15.
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 then the thermostat will be switched on
immediately.
The time delay will change if the temperature drops from the original
calculation.
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.

18 HDT
PO 1 Operating Mode (Normal / Delay Start / TPI)
Time Proportional Integral Mode (TPI)
When the thermostat is in TPI mode and the temperature is rising in the
zone and falls into the Proportional Bandwith 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.
There are 2 settings that will aect the thermostats operation
1. The number of heating cycles per hour
2. The Proportional Bandwith
CyC – Number of Heating Cycles per hour 6 Cycles
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.