Honeywell DHC 23 User manual

H
DIGITAL DISTRICT HEATING CONTROLLER DHC 23
FOR ORIGINAL EQUI MENT MANUFACTURERS
O ERATING INSTRUCTIONS
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Short description 1
Safety notes 2
Operating elements 5
Operation by the user 6
Select operating mode 6
Select temperatures 7
LCD display 8
Adjustment by the user 9
Programming switch 9
Push and turn knob 9
Change switching times 1
Delete switching times 11
Service by the heating specialist 12
Basic settings 12
General functions and operating parameters 12
Special functions and operating parameters for DHC 23-1 14
Special functions and operating parameters for DHC 23-2 15
Special functions and operating parameters for DHC 23-3 15
Adaptation to district heating system 15
Restore basic adjustment 16
Correct the time 16
Battery change 16
Changes of the basic setting 17
Overview of operating parameters DHC 23-1 17
Overview of further operating parameters DHC 23-1 18
Overview of operating parameters DHC 23-2 19
Overview of further operating parameters DHC 23-2 2
Overview of operating parameters DHC 23-3 21
Overview of further operating parameters DHC 23-3 22
Troubleshooting 2
Sensor detection 23
Maintenance and cleaning 23
What to do if it becomes too warm? 23
What to do if it does not become warm? 24
Error messages of the DHC 23 25
Remote control TF 26 26
Connection for remote control TF 26 26
Technical data 27
CONTENTS DHC 23
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1
DHC 23 SHORT DESCRIPTION
■■ Properties of the DHC 2
The DHC 23 is a digital controller for district heating systems. It has the complete
intelligence which is required for optimum control of a modern district heating system.
nOutside temperature compensated time-dependent flow temperature control
nDomestic hot water temperature control
nHeat-up optimization
nDemand dependent pump switching
nAutomatic preventive maintenance operation etc.
Clear arrangement of the operating elements on the front ensure simple
operation.
The remote control TF 26 can be connected to the DHC 23 to operate it
conveniently from the living room.
A patented "Push and turn technique" facilitates simple setting.
Date and time are preset in the factory, as well as the following switching times:
Hot water is heated from 6. to 22. ,
the heating is on from 6. to 22. .
All essential operating parameters can be displayed and changed simple.
Main functions
Simple Operation
Simple setting
Simple commissioning
Service freindliness
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■■ Automatic funktions of the DHC 2
The flow temperature is controlled according to the heat requirement high enough so
that the wanted setpoints of the domestic hot water and of the room temperature are
reached. The room temperature can be regulated accurately using the thermostats
fitted to the radiators.
The DHC 23 selects the latest possible start of the temperature rise so that the required
room temperature is already reached at the set time.
The room temperature is lowered to a programmable value (night setpoint) in the night
during the heating period.
The pipelines are protected against freezing in that if there is a risk of frost, the heating
water circulates. The frost protection function is always active.
The connected sensors are detected and the type of control set to them automatically.
Sensor defects such as line breaks or short circuits are displayed.
The domestic hot water priority guarantees that the domestic hot water has its desired
temperature constantly in the times of domestic hot water readiness. An additional
interruption of the domestic hot water priority is possible.
The DHC 23 limits the return temperature to the value prescribed by the district heating
station.
To enable a temperature measurement in the return even with closed district heating
valve, the district heating valve is opened briefly every 1 minutes when heat is
required.
To avoid the heating circuit pump seizing, it is switched on daily for 1 minute.
The change from summer to winter time is automatic exactly at the correct time.
All data are protected by a battery against a power failure.
Further information on the functions and operating parameters is provided in the
Service by the heating specialist chapter.
Outside temperature compensated
flow temperature control
Heat-up optimization
Night-time cut-off
Frost protection function
Sensor detection
Domestic hot water priority
Maximum limitation of the district
heating return temperature
Interval flushing
Automatic pump preventive
maintenance operation
Summer/winter time change
Data protection
SAFETY NOTES DHC 23
2
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DHC 23 SAFETY NOTES
3
■■ Purpose
The DHC 23 is designed exclusively for regulating and controlling district heating
systems including domestic hot water heating which do not exceed a maximum flow
temperature of 12 °C.
■■ Prerequisite for commissioning
1. The district heating system must be ready and filled with water so that the pumps
do not run dry.
2. The control device must be installed according to the installation instructions.
3. All electrical connections (power supply, valve actuators, pumps, sensor wiring, etc.)
must be made by the specialist according to the valid VDE regulations and
correspond to the corresponding circuit diagrams (see installation instructions).
4. If an underfloor heating system is connected, a limiting thermostat must be installed
by the customer in addition in the flow line after the heating circuit pump to switch
the pump off at too high flow temperatures.
If all these conditions are fulfilled (have them checked by the heating
specialist), the controller can be put into service.
The current time and date are already set in the factory and protected by a battery.
The timer works according to a basic program and the control functions are preset for
customary district heating systems.
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SAFETY NOTES DHC 23
4
■■ Domestic hot water temperature above 60 °C
Note that in the following cases there is a risk of scalding at all domestic hot water
taps (kitchen, bathroom, etc.)! In these cases mix sufficient cold water.
In the manual mode, the domestic hot water can be heated up to the maximum
possible flow temperature. This mode is used especially if the DHC 23 should be
defective. However, the high domestic hot water temperatures can be avoided by
switching off the domestic hot water charging pump by hand using the switch on the
pump (if present).
Temperature setting on the DHC 23 The domestic hot water temperature can be
set on the DHC 23 up to 75 °C
■■ Do not separate the DHC 2 from the power supply
The battery for protecting all individual data is otherwise loaded and must be replaced
prematurely.
The frost protection function of the DHC 23 is otherwise put out of operation.
Manual mode
Temperature setting on the DHC 2
Data protection
Frost protection function
⁄
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⁄
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DHC 23 OPERATING ELEMENTS
5
To be able to handle the district heating controller DHC 23 well, it is divided into 3
operating levels:
■■ Operation by the user
In this level the user sets the basic heating functions. The operating elements required
for this are fitted on the front.
Operating mode switch:
The operating mode of the DHC 23 can be selected with the operating mode switch
(e.g. "Normal operation").
Room temperature set knob:
The room temperature can be selected with this knob.
Domestic hot water temperature set knob:
The domestic hot water temperature can be selected with this knob.
■■ Adjustment by the user
In this level the user can make an individual change to the basic factory setting.
Grasp the recessed grip on the left behind the flap, pull it slightly and open the flap
downwards. The following operating elements are fitted behind it:
Programming switch
With the programming switch you can select whether heating times or times for
domestic hot water readiness should be changed.
Push and turn knob
With the push and turn knob you can (in combination with the programming switch)
change the heating times or the times of domestic hot water readiness..
■■ Service by the heating specalist
In this level the service personnel can perform service and maintenance work. The
operating element required for this, the service switch, is fitted behind the cover.
Service switch
With the service switch, the service personnel (in combination with the programming
switch) can check and change the operating parameters of the DHC 23.
1st operating level:
2nd operating level:
rd operating level:
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OPERATION BY THE USER DHC 23
6
■■ Select operating mode
The operating modes of the DHC 23 can be set with the operating mode switch.
The meaning of the individual positions is illustrated by symbols.
Normal mode
Heating and domestic hot water readiness are switched on corresponding to
the set switching times. The set room temperature is assured at the set heating
times.
The domestic hot water has the set temperature in the times of domestic hot
water readiness.
Off mode
Heating and domestic hot water readiness are switched off. Frost protection for
the heating system is active. If there is risk of frost, a temperature corresponding
to the night set temperature value is regulated (reduced temperature). This
setting is practical for holidays, for instance.
Continuos heating mode
The heating is on right round the clock. Domestic hot water readiness is
switched on corresponding to the set switching times.
Manual mode
For commissioning or for emergency operation.
Heating and domestic hot water are in uncontrolled continuous operation.
The pumps can be switched on and off provided a switch is fitted to the pumps.
The valve can be adjusted arbitrarily manually.
Domestic hot water readiness
Only domestic hot water readiness is switched on corresponding to the set
switching times. The heating is not on.
This setting is intended for the summer months.
Operating mode switch
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DHC 23 OPERATION BY THE USER
7
■■ Select temperatures
Select room temperature
The setpoint for the room temperature can be set with the aid of the room temperature
knob between 8°C and 32°C.
The room setpoint can also be set with the remote control TF 26.
In the normal operating mode, the set room temperature is maintained during the
set heating times, in the continuous heating mode constantly.
If you want to heat outside the set heating times, you must set the operating mode
switch to .
If you do not want to heat within the set heating times, you must set the operating mode
switch to or .
Select domestic hot water temperature
Warning:
With domestic hot water temperatures above 6 °C there is danger of scalding at
all domestic hot water taps (kitchen, bathroom ...). You must then mix cold water
sufficiently.
The domestic hot water temperature can be set with the aid of the domestic hot water
temperature knob between 35°C and 75°C.
The set setpoint is always the cut-in value. The domestic hot water charging is
completed after reaching a switching difference (+ 5 K).
In the normal mode, continuous heating mode and domestic hot water rea-
diness modes, this temperature is controlled during the set times of domestic hot
water readiness, domestic hot water heating is switched off in between.
If you want to have domestic hot water at other times (e.g. early in the morning), you
must change the times of domestic hot water readiness (see Adjustment by the
user chapter).
⁄
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OPERATION BY THE USER DHC 23
■■ LCD display
Weekday current
(2 = Tuesday) time
Bars of the heating times of the current day:
1 bar = 3 minutes heating
If the operating mode switch is at auto, and you have not changed the switching times
set in the factory, the bars extend from 6. to 22. . This means that the heating is on
continuously from 6. to 22. .
The weekday and the current time appear on the left below.
1 = Mo … 7 = Su
On the right next to the time, symbols show the operating state of the DHC 23 or
which parts of the system the DHC 23 is just controlling. The following symbols can
appear:
The heating is on currently.
The heating is off currently
The domestic hot water is currently being heated (domestic hot water
readiness).
▲The district heating valve opens.
▼The district heating valve closes.
The district heating valve is in neutral position (no triangular symbol).
The heating circuit pump is working.
The domestic hot water charging pump(s) works (work).
Caution: The DHC 23 has detected an error (see Error messages of the
DHC 2 section).
Heating is on continuously from 6. to 22.
8
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9
DHC 23 ADJUSTMENT BY THE USER
Grasp the recessed grip on the left behind the flap, pull it slightly and open the flap
downwards. Two knobs are located behind it.
■■ Programming switch
The left knob is the programming switch, it has five positions.
The auto position is the normal position; this position is not used for adjusting the
system by the user.
In this position the switching times for the heating (heating times) can be set. 4 swit-
ching times (i.e. 2 periods) for heating are available for each individual weekday (see
Change switching times section).
In this position the switching times for domestic hot water readiness can be set. 4 swit-
ching times (i.e. 2 periods) are available for domestic hot water readiness for each indi-
vidual weekday (see Change switching times section).
In this position the outside temperature is displayed; this position is not used by the
user for setting the system.
In this position the switching times of the circulation pump can be set..
■■ Push and turn knob
The right knob is the push and turn knob. It can be pushed and turned and is used for
changing the set values.
The values to be changed are selected by pushing and then flash. Flashing values can
be changed by turning. The change is temporarily stored by pushing once again.
Programming switch
Push and turn knob
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1
ADJUSTMENT BY THE USER DHC 23
■■ Change switching times
The DHC 23 is already equipped in the factory with a basic setting for the switching
times for heating and domestic hot water which satisfies normal requirements.
You can change this basic setting simply at any time.
1. Open the flap of the DHC 23.
2. Set the setting switch to , or according to whether you want to
change the switching times for heating, domestic hot water or circulation pump.
An A appears in the bottom left of the display (the switching times can be changed
simultaneously for all weekdays in this position) or a number of a weekday (1 = Mo
... 7 = Su). Black bars show the times in which the heating is on on the relevant
weekday (or domestic hot water readiness is switched on). The 1st cut-in time
appears instead of the current time.
Note:
Firstly make all changes which concern all weekdays (A). Only then make the
settings of the individual weekdays (weekdays 1 ... 7). Proceeding in the reverse
order has the effect that the setting of the individual weekdays is overwritten.
3. Now make the setting with the push and turn knob:
Push knob: A or the weekday flashes.
Turn knob: The weekday changes and continues to flash. Turn it until the
weekday to be changed flashes or A, if you want to change the
switching times affecting all weekdays.
Push knob: The 1st cut-in time flashes, also the 1st bar in the display
and .
Turn knob: The flashing bar moves along, at the same time the flashing
cut-in time changes in 1 -minute steps.
Push knob: The 1st cut-off time flashes, also the bar for cutting off and .
Turn knob: The flashing bar moves along, at the same time the flashing
cut-off time changes in 1 -minute steps.
The 2nd cut-in time and the 2nd cut-off time are determined by
repeating this process (push knob, turn knob, push knob,
turn knob).
Push knob: Then you must push the push and turn knob once again to
confirm all switching times, in this way the new cut-in and cut-off
times are stored in the DHC 23.
Caution:
If you set to auto, as long as a bar and a switching time are still flashing, the
previously changed switching times are not stored.
Perform this process until all required switching times are set.
4. Set the setting switch back to auto.
5. Close the flap again.
Programming switch
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11
DHC 23 ADJUSTMENT BY THE USER
■■ Delete switching times
2 switching times are deleted by setting the cut-in time and cut-off time exactly equal,
i.e. 12: cut-in and 12: cut-off.
For this purpose simply move the cut-off bar over the cut-in bar.
After confirmation of all switching times, the deleted switching times are no longer dis-
played.
The deleted switching times become visible again by pushing and turning (to the right
or left).
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SERVICE BY THE HEATING SPECIALIST DHC 23
12
■■ The basic settings of the adaptable functions
The DHC 23 controller is preset in the factory with expedient control parameters.
These basic settings should cover a large part of the standard applications. However,
to be able to satisfy special requirements, it is additionally possible to adapt important
control parameters or functions.
■■ General functions and operating parameters
The following functions and operating parameters apply for all 3 DHC 23 types. The
number behind the described parameter (x) indicates the service switch position with
which the parameter can be selected. Bring the programming switch into the "auto"
position (normal position) for this. If the symbol appears behind the parameter
number "additionally", then the programming switch must previously be brought into
the position.
The current time and the current date were already set in the factory. Leap years are
taken into account automatically as well as summer and winter time.
The DHC 23 ensures that the setpoint of the flow temperature never exceeds the set
maximum value.
The room temperature is lowered during the heating period in the night to the set night
setpoint (night cut-off).
If the outside temperature drops below the frost protection limit, the heating circuit
pump is switched on.
According to outside temperature, a setpoint for the flow temperature between 2 °C
and 9 °C results through the heating characteristic. The heating characteristic slope
refers to -2 °C outside temperature. The curvature of all heating characteristics is
uniformly 1.33.
The heat-up optimization has the effect that the start of heating up of the heating system
is defined according to outside temperature so that the set room temperature is rea-
ched already at the set heating times.
This advancing of the heating up start depends upon the building construction:
Light construction = latest temperature rise start,
Heavy construction = earliest temperature rise start.
If a heat-up optimization should be performed, the building construction must therefore
be entered. "Light construction" should be entered for instance for a prefabricated
house, "heavy construction" e.g. for massive construction.
The valve motor running time is the time which the actuator needs to drive the district
heating valve from one end position (closed) to the other end position (open). The run-
ning time may have to be adapted only if motors other than the customary
HONEYWELL motors are connected.
Up to the set value, the DHC 23 works as two-point controller; this function simplifies
calorimetry in reduced load operation.
Time and date
(Service switch position and 1)
Maximum flow setpoint (2)
Night setpoint (3)
Frost protection limit (4)
Heating characteristic slope (5)
Heat-up optmization (6)
Valve motor M 1 running time(7)
District heating valve minimum
liftl (A)
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13
DHC 23 SERVICE BY THE HEATING SPECIALIST
Some district heating utilities require minimum volume flows in their networks, this
can be achieved by a high temperature difference between flow and return. The
required temperature spread is assured by the maximum limitation of the district
heating return temperature. With the maximum limitation, both a fixed value limitation
can be performed and a floating limitation can be realized according to the outside
temperature by setting the parameters. Fixed value limitation to 5 °C, for instance,
means that the district heating return temperature will not exceed this value over the
entire outside temperature range.
However, it is desirable at higher outside temperatures to shift this maximum limitation
downwards, i.e. to perform a floating district heating return temperature limitation. In this
way the lowest possible district heating return temperature is achieved, assigned to the
relevant outside temperature and thus good heat utilization.
The values for the maximum limitation of the remote heating return temperature and
the onset point of the floating remote heating return temperature limitation in heating
mode can be set, the floating return temperature limitation can be switched off by
selecting 1 °C as onset point.
Return temperature onset point of the floating
limitation return temperature limitation
Example 1: 9 °C 1 °C factory setting
Example 2: 5 °C 1 °C Fixed value limitation
Example 3: 8 °C 5 °C
Example 4: 5 °C –1 °C
The reset time of the flow temperature controller can be adapted in critical systems.
The stability of the control is influenced by the controller gain. If the district heating
valve oscillates constantly open and closed, the controller gain must be set to a smaller
value. If the system takes too long until the room setpoint is reached, then the controller
gain should be increased.
The DHC 23 switches over automatically from summer to winter time. The change from
winter to summer time is made in the last weekend in March. The change back is
made in the last weekend in October. If the change-over dates should change, these
can be adapted.
Maximum district heating return
temperature in heating mode (B),
onset point of floating district
heating return temperature
limitation. (C)
Reset time (D)
Controller gain(E)
Summer/winter time change
(D) + ( )
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14
SERVICE BY THE HEATING SPECIALIST DHC 23
■■ Special functions and operating parameters
for DHC 2 -1
If the DHC 23 is controlled at the input TW by a system other than the remote control
TF 26, it must be possible to ignore a signal applied at this input. Activating this
function has the effect that the applied signal is taken into account only up to the next
switching time and then ignored.
The inlet temperature in the external domestic hot water heat exchanger can be limited
upwards to prevent calcification. This function is active only in layered domestic hot
water storage tank operation (DHC 23-1).
In problematic systems, the switching difference between cut-in and cut-off temperature
can be changed.
This switching difference influences the duration of the charging pump run-on in
layered domestic hot water storage tank operation.
During domestic hot water charging, the return temperature limitation can be
cancelled. The higher values for the return temperature allowed for this special case
are determined here
The entry of min. (time set in the factory) is treated as absolute domestic hot water
priority: The heating circuit pump is switched off as long as domestic hot water is being
charged. However, should the heating circuit cool down too much because of domestic
hot water charging, the DHC 23 can be set to interrupted domestic hot water priority by
changing the value from min. (e.g. to 15 min.). The domestic hot water charging
pump and heating circuit pump then alternate and are operated in each case as long
as entered here (e.g. 15 min.).
Overwrite TF 26 status (8)
Maximum inlet temperature in the
WW heat exchanger VF1(9)
Layered domestic hot water stora-
ge tank switching difference
(9) + ( )
Switching difference for domestic
hot water pump run-on (A) + ( )
Maximum district heating return
temperature with sole domestic hot
water charging (B) + ( )
Time interruption of domestic hot
water priority (C) + ( )
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15
■■ Spezial functions and operating parameters
for DHC 2 -2
The 6th relay can activate both the circulation pump and the pump of the layered hea-
ting circuit.
A separate room setpoint can be set for the layered heating circuit.
The heating characteristic slope for the layered heating circuit can be set separately.
Temperature selector input
The remote control TF 26 can act only on one heating circuit or both heating circuits
are operated through the remote control.t.
Configuration of the 6th relay (9) + ( )
Layered heating circuit setpoint
(A) + ( )
Layered heating circuit heating
characteristic slope (B) + ( )
Temperature selector input (C) + ( )
■■ Adaption to district heating system
1. Open flap.
2. Withdraw cover.
Caution: Sensitive electronic components are located behind the cover.
Do not handle with objects inside the unit..
3. Bring the programming switch into the auto or. position.
4. Bring the service switch into the required position with a small screwdriver. The
position of the service switch and the value of the associated operating parameter
appear in the display instead of the weekday and the time.
5. Now make the change with the push and turn knob:
Push knob: The corresponding value flashes in the display.
Note: To change the year (service switch in position 1) push the
knob 2 times: After the first push the day and month can be chan-
ged, after the second push the year
.Turn knob: The value changes and can be adapted.
Push knob: The values flashes no longer and is adapted.
6. Bring the service switch back to position. Thus the weekday and the current time
are displayed again during operation.
7. Reattach the cover.
8. Close the flap again.
Service switch
Push and turn knob
Programming switch
DHC 23 SERVICE BY THE HEATING SPECIALIST
■■ Spezial functions and operating parameters
for DHC 2 -
The valve actuator running time is the time which the actuator needs to drive the valve
from one end position into the other end position "open". Only if actuators other than
the usual Honeywell motors are connected may the running time have to be adapted.
The reset time of the control circuit M2 can be adapted in critical systems.
The stability of the control is influenced by the controller gain. If the district heating
valve oscillates constantly open and closed, the controller gain must be set to a smaller
value. If the system requires too long until the room setpoint is reached, then the
controller gain should be increased.
The return temperature limitation can be cancelled during domestic hot water charging.
The higher value for the return temperature allowed for this special case is determined
here.
Valve actuator M2 running time (8)
Reset time (9) + ( )
Controller gain (A) + ( )
Maximum district heating return
temperature with sole domestic
hot water charging (B ) + ( )
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16
SERVICE BY THE HEATING SPECIALIST DHC 23
■■ Restore basic setting
Warning: All individual adaptations to the district heating system are lost when the
factory basic setting is restored.
Proceed as follows to restore the basic factory setting:
1. Open the flap of the DHC 23.
2. Switch off the power supply.
3. Switch the power supply back on with the push and turn knob pushed.
4. Release the push and turn knob.
The number 1 flashes in the display on the left below as error message.
5. Turn the programming switch to and back again to delete the error display
6. Close the flap.
If the basic factory setting is restored, any faults on the connected inputs are displayed
as error messages.
■■ Correct the time
If the clock becomes fast or slow in the course of the years, it can be set:
1. Open the flap of the DHC 23.
Note: The programming switch must stand at auto.
2. The time is now corrected with the push and turn knob:
Push knob: Time flashes
Turn knob: Correct time.
Push knob: Time no longer flashes and is corrected.
3. Close the flap again.
■■ Battery change
Warning:
Do not separate the DHC 23 from the mains during the battery change, otherwise all
individual data are lost.
The battery serves for storing the set data in the case of a power failure. So that no
data are lost on a power supply failure even after a lengthy operating time of the DHC
23, it is recommended that the battery is changed as a precaution every 8-1 years.
1. Open the flap of the DHC 23.
2. Withdraw the cover.
Caution:
There are sensitive electronic components behind the cover. Do not handle with
objects in the interior of the unit.
You will find the battery on the left behind the cover (button cell).
3. Withdraw the old battery and insert a new battery with the plus pole (+) to the left.
Battery type: CR 2 32 3 V (e.g. Varta, Panasonic).
4. Reattach the cover.
5. Close the flap.
⁄
!
⁄
!
Programming switch
Push and turn knob
Service switch
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17
DHC 23 SERVICE BY THE HEATING SPECIALIST
■■ Changes of the basic setting
It is possible to adapt important control parameters or functions for service purposes as
well as for adapting to special requirements. Proceed as follows:
qTurn programming switch into auto position.
wDifferent values can be displayed by turning the service switch into the positions
... F (see Table).
eThe parameters can then be changed with the aid of the push and turn knob..
Programming switch
Service switch
Push and turn knob
■■ Overview of operating parameters DHC 2 -1
Position Operating parameter Range Basic setting
Time : ...23:59 current time
1 Day, month or year 199 ...2 89 current date
2 Max. flow setpoint 3 ... 12 °C 9 °C
3 Night setpoint ...2 °C 1 °C
4 Frost protection limit -1 ...15°C 2°C
5 Heating characteristic slope .4...4.5 1.6
6 Building construction
for optimization , 1, 2, 3
= optimization off
1 = light construction
2 = medium construction
3 = heavy construction
7 Valve actuator M1 running time 1 ...18 s 12 s
8 Overwrite TF 26 status ,1
= do not overwrite
1 = overwrite
9 Max. inlet temperature in * 4 ...9 °C 9 °C
WW heat exchanger (VF1)
A = 1 District heating valve minimum lift ...3 % %
B = 11 Maximum district heating return 4 ...9 °C 9 °C
temperature in heating mode
C = 12 Onset point of floating distant -2 ...1 °C 1 °C
heating return temperature limitation
D = 13 Reset time 1...3 min. 3 min.
E = 14 Controller gain 1...3 %/K 3 %/K
F = 15 (not used)
* Valid only for layered domestic hot water storage tank operation
} M 1
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18
■■ Overview of further operating parameters DHC 2 -1
qTurn programming switch into position.
wFurther parameters can be displayed and changed by turning the service switch
into the positions 9....D.
eThe parameters can then be changed with the aid of the push and turn knob.
Programming switch
Service switch
Push and turn knob
Position Operating parameter Range Basic setting
Outside temperature only display
1 Flow temperature only display
2 District heating return temperature only display
3 Domestic hot water temperature upper* only display
4 Domestic hot water temperature lower* only display
5 Domestic hot water charging temperature* only display
6 Room temperature setpoint only display
7 Flow temperature setpoint only display
8 Maximum setpoint of the district only display
heating return temperature
9 Layered domestic hot water
storage tank switching -1 ...2 K °C
difference* WW1 and WW2
A = 1 Switching difference for* ...1 K 1 K
domestic hot water pump run-on
B = 11 Maximum district heating return 4 ...9 °C 9 °C
temperature with sole domestic
hot water charging
C = 12 Absolute priority min. min.
time interruption of hot water priority 1...3 min.
parallel mode 4
D = 13 Automatic summer/winter time 5: 3/ 5:1
E = 14 Current valve position M1 only display
F = 15 Software version
* Only for layered domestic hot water storage tank operation
SERVICE BY THE HEATING SPECIALIST DHC 23
10878_BDA_DHC23_engl_neu 06.09.1999 13:50 Uhr Seite 20