Compit R551 User manual

Str. 1
Pb
COMPIT ul. Wielkoborska 77a, 42-200 Czêstochowa, tel./fax [phone]
www.compit.eu
manual version 2
R551
WEATHER-DEPENDENT BOILER CONTROL SYSTEM WITH
THERMAL MIXING VALVE CONTROL
AND DOMESTIC HOT WATER LOADING
models from u20 to u29

Str. 2
CAUTION!
- Before installation read the operating instructions and warranty terms and conditions
carefully. Faulty installation, maintenance and use of the controller will invalidate the
warranty.
- Any installation work can be carried out only after power supply has been discon-
nected:
- for RAPID controllers - after the power supply cord has been unplugged
- for others – after disconnecting power and making sure that the voltage on the termi-
nals is not hazardous.
- All wiring and mounting should be done by an authorized person in accordance with the
regulations and standards in force.
- Do not install or use the controller if its housing has been damaged. Electric shock
hazard!
- The wiring system to which COMPIT controller is connected should be protected with
appropriate safety fuses.
- Before the controller is used for the first time, check if the wiring is in accordance with
the present instructions and whether the controller's power supply conforms to all the
requirements.
- Any repairs to the controller can be done exclusively by the manufacturer’s service.
The warranty is not valid in case of repairs carried out by unauthorized persons.
- This controller is not a safety device! In systems liable to damage due to automatic
control failure, it is necessary to install an extra safety device with appropriate certifi-
cates of approval. For systems that cannot be switched off, the control system must be
designed in such a way that it can operate without the controller.
All Declarations of Conformity are available at www.compit.pl
Disposal of waste electrical and electronic equipment (applies
to private households only)
The symbol of the crossed-out wheeled bin placed on COMPIT products or in the
accompanying operating instructions means that disposal of waste electrical and electronic
equipment (WEEE) along with other waste is not allowed. Equipment marked with this
symbol that can be recycled, reused or where subassemblies can be recovered should be
returned to a specialised collection facility, where it is collected free of charge. This product
can be returned to a local distributor on purchase of new equipment.
Appropriate recycling should be carried out so as to avoid negative impact on the
environment and human health. Inappropriate storage or treatment shall be subject to pen-
alties as provided for in relevant regulations.

Str. 3
1USE
The device has been designed for controlling central heating (CH) coal boiler with a boiler
feeding mechanism according to the weather characteristics or at constant temperature,
controlling the mixing valve according to the outdoor temperature sensor or at constant
temperature, and domestic hot water (DHW) tank loading. Additionally, it is possible to
connect two room thermostats for boiler circulation and mixer.
2OPERATION
R551 control system is designed to control the operation of central heating coal boiler ac-
cording to the weather characteristics. Smooth control of the blower reduces the amount of
air supplied during the combustion process. Weather-dependent control of the mixer allows
for reducing the circulation temperature when compared to the boiler temperature, which
protects the boiler and ensures optimum CH temperature. Domestic hot water loading con-
trol guarantees fast and boiler-safe supply of hot water.
Thermostat 1
Thermostat 2
R551 controller operation diagram
2.1 CENTRAL HEATING BOILER OPERATION
When weather-dependent operation mode has been selected in the “CH OPERATION”,
the set temperature is adjusted according to the heating curve on the basis of the outdoor
temperature (see ADJUSTING THE SET TEMPERATURE ACCORDING TO THE WEATHER
CHARACTERISTICS). If the constant temperature mode has been selected, the set CH
temperature takes the value of the “set CH temperature” parameter.
BOILER OPERATING MODES:
START-UP
To proceed to the START-UP mode leave the SWITCH-OFF mode by pressing “PRACA/
STOP” [OPERATION/STOP] key. The “PRACA” LED light begins to flash. The “+” key is

Str. 4
used to enable the feeder and the “-” key is used to start the blower. After the “?” key is
pressed, the display shows the speed of the blower which can be adjusted by using the up/
down arrow keys. After starting-up the boiler, press “PRACA/STOP” [OPERATION/STOP]
key to enter the OPERATION mode.
NOTE: YOU MUST NOT LEAVE THE BOILER UNATTENDED IN THE START-UP MODE!!!
OPERATION
The OPERATION mode is engaged if boiler temperature is lower than the set temperature
(determined by the weather characteristics). When in the OPERATION mode, the feeder
engages cyclically in order to feed in a new portion of coal for burning. The feeder operating
time and feeding break time are determined in the controller parameters: “t0 – feeder
operating time – OPERATION” and “t1 – feeding break time – OPERATION”.
The blower always switches on 5 seconds before the feeder starts operating in order to
enhance burning of another coal feed and it blows all through the feeding time. When the
feeding is finished, the blower operates for the length of time determined in “t4”. The blower
can work throughout the whole cycle if the “t4” parameter value is higher than the “t1”
parameter value.
t0 - feeder operating time in the OPERATION mode
t1 - feeding break time in the OPERATION mode
t4 - blower operating time
Once the boiler reaches the target temperature, the controller engages the blower to blow
through the boiler chamber for the “t5” time and then goes to the MAINTENANCE mode.
MAINTENANCE
In the MAINTENANCE mode the amount of the heat produced is reduced to a minimum
necessary for maintaining combustion. The MAINTENANCE mode is on if boiler tempera-
ture is higher than the set temperature (according to the heating characteristics). In this
mode the blower always switches on 5 seconds before the feeder, the feeder operates for
the time set in “t2” – feeder operating time – MAINTENANCE”. Once the coal feed is
finished, the blower continues operating for the time specified in ”t4 – blower operating
time” and then it switches off. The next cycle of the boiler blow-through and coal feed is
started after time set in “t3 - feeding break time – MAINTENANCE”. The controller will

Str. 5
SHUT DOWN
The boiler is SHUT DOWN when the user presses the “PRACA/STOP” [OPERATION/
STOP] key and holds for over 2 seconds while in the operation or maintenance mode.
BURN-OUT
The BURN-OUT mode is enabled when boiler temperature is lower than “boiler shut down
temperature” for a period exceeding the time set in boiler shut down blocking time. In the
BURN-OUT mode both the feeder and the blower are shut down. This mode is marked by
the EMERGENCY relay switching on.
switch from the MAINTENANCE mode when the boiler temperature falls below the set
temperature of the boiler – minus hysteresis.
t2 - feeder operating time in the MAINTENANCE mode
t3 - feeding break time in the MAINTENANCE mode
t4 - blower operating time
2.2 ADJUSTING THE SET TEMPERATURE ACCORDING TO THE WEATHER
CHARACTERISTCIS.
The set temperature is determined on the basis of the measured outdoor temperature and
the programmed heating curve. The curve is obtained by defining set boiler temperature for
5 outdoor temperature values:
Shut down outdoor temperature – when this temperature is exceeded the mixer
circulation is off, boiler pump is shut down and boiler set temperature switches to mini-
mum;
At T ext +10 Tch set – boiler set temperature at outdoor temperature of +10°C;
At T ext 0 Tch set – boiler set temperature at outdoor temperature of + 0°C;
At T ext -10 Tch set – boiler set temperature at outdoor temperature of -10°C;
At T ext -20 Tch set – boiler set temperature at outdoor temperature of -20°C.
Mixer characteristics is defined by exactly the same parameters.
If the measured outdoor temperature is between those values, the controller calculates
central heating set temperature on the basis of 2 closest values. E.g. with outdoor tempera-
ture of -5°C, programmed value of the curve for T ext 0 = 40°C and for T ext -10 = 50°C, the
controller will set the central heating target temperature at 45°C.

Str. 6
The set value calculated from the curve is also influenced by the thermostat and the timer.
However, the calculated boiler temperature may not be lower than the value determined in
“Minimum boiler temperature” or exceed the “Maximum boiler temperature”. Similarly, set
mixer temperature may not exceed the “Maximum mixer temperature”.
An example of adjusting the central heating temperature has been presented below:
Set CH temperature
External temparature
100
90
80
70
60
50
40
30
-20-15-10-5051015
BOILER OPERATION WITH ROOM THERMOSTAT.
Opening of the W2 terminal shuts down the boiler pump after the time set in “CH pump
overrun time” lapses. If the parameter is set at “no shut down operation”, then the pump will
operate with the thermostat terminal open. CH (boiler) set temperature will drop to the value
set for the mixer + 5°C (not lower, however, than boiler minimum temperature). The tem-
perature set at this value is to ensure enough heat for the mixer.
2.3 BOILER PUMP OPERATION
The boiler pump works when:
- It is the heating season (T ext is lower than “Shut down outdoor temperature”)
- W terminal of the room thermostat is closed
- Boiler temperature exceeds the CH pump turn-on temperature
The boiler pump can be shut down when:
- The heating season is over (T ext exceeds the “Shut down outdoor tempera
ture”)
- W terminal is open
- Boiler temperature drops below the CH pump turn-on temperature
- Priority hot water is loaded
CAUTION: When the boiler temperature exceeds the maximum value, the CH and DHW
pumps are enabled in order to reduce the boiler temperature.

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2.4 DHW TANK LOADING
The tank is loaded when its temperature falls below the set temperature (T DHW set). The
controller sets the target boiler temperature according to the set boiler temperature for
loading the DHW tank. When the boiler temperature exceeds the tank temperature and the
CH pump turn-on temperature, the pump loading the tank is switched on. Loading is fin-
ished when the tank reaches the set temperature. The set boiler temperature returns to the
temperature set by the user. The loading pump continues to operate for time depending on
“HW pump overrun time” parameter to unload the boiler and is then shut down. If priority
HW loading takes place, the boiler and mixer pumps are shut down.
2.5 OPERATION WITH MIXER
R551 controls one mixing valve circulation according to constant temperature or weather
characteristics (appropriate mode is selected in “MIXER OPERATION”). If weather-de-
pendent operation mode has been selected, the set value is calculated in the same way as
for the boiler (see p. 5). If constant value type of control has been selected, the mixer
maintains the temperature determined in “Mixer set temperature”. Mixer circulation is
controlled by gradual closing and opening of the valve. The bigger the difference between
the measured and set temperature, the more frequent and longer the cycles of opening and
closing of the valve. If the measured temperature equals the set temperature, the controller
does not engage the cylinder. How fast the cylinder responds to the changes in measured
temperature depends also on the “Mixer dynamics” parameter which should be suitable
for the controlled unit. Setting a higher value results in faster response, but it may lead to
oscillations. It is advisable to observe the operation of the control system and if the re-
sponse is too slow, the dynamics should be increased, while with too fast a response it
should be reduced. The mixer pump works if:
- It is the heating season
- Boiler temperature exceeds CH pump turn-on temperature
- Calculated mixer set temperature exceeds 0°C, this can be caused by timer
reductions
- DHW is not loaded
NOTE: the controller works exclusively with 3-point cylinders fitted with limit switches. The
cylinder moves only during the opening or closing signal input. When there is no signal it
cannot change its position. Thermal cylinders with analogue input or return spring may not
be applied.
OPERATION WITH ROOM THERMOSTAT. When the W1 terminal is open the value calcu-
lated from the heating curve is lowered by the “Mixer reduction” parameter. Thermostat
reduction is added to timer adjustments and if the calculated mixer set temperature is lower
than 0°C the controller will engage the mixer pump. If room thermostat is not connected,
“Mixer reduction” should be set at 0°C.
2.6 OUT OF SEASON OVERRUNS
When out of season, after the shut down outdoor temperature has been exceeded, pump
and mixer overrun takes place. Every Monday at 12:00 CH pump is engaged for 5 minutes
and the valve is closed. Then the pump is off and the controller opens the valve for 4
minutes. The last stage involves closing the valve for 5 minutes.

Str. 8
2.8 EMERGENCY SITUATIONS
The controller signals 3 emergency situations. The first one – when boiler temperature
exceeds 95°C. The EMERGENCY relay is on. This emergency can be cancelled by press-
ing the START/STOP key after the temperature falls below 95°C. This emergency results in
switching to the OFF mode. The second situation – in the case of a flareback on the coal
feeder (feeder temperature exceeds “Maximum feeder temperature” – the display will read
“FEEDER OVERHEATED” while reading feeder temperature. To respond coal should be
fed for 10 minutes, blower should be switched off and EMERGENCY relay should be on.
The emergency may be cancelled by pressing the START/STOP key. However at tempera-
ture 10°C lower than the emergency value the control system tries to despose of the burning
fuel from the feeder – the feeding break time is two times shorter and additionally in the
MAINTENANCE mode coal feeding time is two times longer. The third emergency situation
is the boiler burn-out. It takes place if boiler temperature falls below the boiler shut down
temperature and remains at this level for longer than boiler shut down blocking time.
If there is no communication between the system and the display, CH and DHW pumps are
engaged and blower, feeder, mixer pump and the valve drive are off. Also the EMERGENCY
output terminal is on.
NOTE: Inappropriate parameter settings may result in faulty boiler operation and in extreme
situations, in boiler failure.
3TIMER
The control system is equipped with an internal timer, which affects the set temperatures for
the boiler, mixing valve circulation and DHW. Boiler, mixer and DHW tank have separate
timer zones. For the boiler and mixer 4 time zones may be programmed per 24 hours (from
A to D), separately for weekdays and for Saturdays and Sundays. For each zone the start
time is set and the adjustment value added to the set value (calculated from the heating
curve or in the case of boiler determined by the user). Those adjustments can have positive
and negative values and thus they may either raise or lower the set value. However, the
temperature calculated for the boiler (including the adjustments) may not be lower than the
temperature determined in “Boiler minimum temperature” or higher than “Maximum
boiler temperature”.
T set = T curve + timer adjustment – thermostat reduction
If zone A of the timer (parameter “Mon-Fri.CH.ZoneA Start”) is programmed at 6:00 and
the adjustment (“Mon-Fri.CH.ZoneA Adjustment”) at -8°C, then the set temperature (cal-
culated from the curve) will be lowered by the adjustment value (8°C) beginning with that
time. If the adjustment value is +10°C, then the set temperature (e.g. calculated from the
curve) will be raised by the (10°C). The adjustment value shall remain unchanged until
another zone starts. If zone B is programmed to start at 14:00, then after this hour the
adjustment for A stops to apply and the adjustment for zone B is applied. The rule is the
same for other zones. If a given zone is not used, its value may be set at —:— (next after
23:50) and it will be ignored. Saturday and Sunday zones are programmed similarly to
weekdays.
In order to lower DHW set value by “DHW reduction” two time zones are used
both for weekdays and Saturdays/Sundays. The user decides on the reduction starting and
finishing time.
When the power is off, the timer operates on batteries for at least 48h. However it
must be power supply operated for at least 12 hours prior to this for the batteries to re-
charge.

Str. 9
4. CONTROLLER HANDLING
Four keys are used to operate the controller:
Press this key to switch between boiler operating modes.
Press the “?” key to start editing the parameters.
Press the “+” and “-” keys to view the parameter list and after
enabling the editing mode by pressing “?” – to change the parameter
values. In the START-UP mode the “+” key is used to start the
feeder and the “-” key is used to start the blower.
Output status is visualised through LEDs on the control panel:
- boiler pump in operation (P CH)
- DHW tank loading
- blower
- feeder
The controller operates in one of the following modes:
SWITCH-OFF mode – this mode is entered manually from either the OPERATION or the
MAINTENANCE mode when the “PRACA/STOP” [OPERATION/STOP] key has been
pressed and held for 3 seconds. The blower and feeder are switched off.
START-UP mode – this mode is entered manually from the SWITCH-OFF mode by press-
ing the “PRACA/STOP” [OPERATION/STOP] key. Both the blower and feeder can be
switched on manually by pressing the “+” and “-” keys. Press the “PRACA/STOP” [OP-
ERATION/STOP] key to leave the START-UP mode and the controller will switch to the
OPERATION or MAINTENANCE mode.

Str. 10
OPERATION mode – this mode is entered from the START-UP mode if boiler temperature
is lower than the set temperature. Having reached the set temperature the controller auto-
matically switches to the MAINTENANCE mode.
MAINTENANCE mode – this mode allows for maintaining the combustion only. When the
boiler temperature falls below the set temperature, the controller automatically switches to
the OPERATION mode.
BURN-OUT mode – the controller switches to BURN-OUT from the OPERATION mode
when for the time set in boiler shut down delay the boiler temperature is lower than the boiler
shut down temperature. The burn-out is signalled by switching on the emergency relay and
the EMERGENCY LED. Press the “PRACA/STOP” [OPERATION/STOP] key to switch to
the SWITCH-OFF mode.
After the power supply is on the dispay shows boiler measured temperature, set tempera-
ture and the current operating mode. Using the arrow keys we can navigate among the
readings. The last parameter on the list is “GRUPA” [GROUP]. In this window the next
group of parameters to be viewed can be selected and edited.
When code 99 is entered, “?” key is used to change between parameter value editting
function and parameter list scrolling function. The arrow keys may be used to change the
parameters. To change a parameter value:
1. Select CODE parameter using the arrow keys.
2. Press “?”. The display will show “?”, which means parameter value editing mode.
3. Set CODE at 99 using the arrow keys.
4. Press “?”. ? will disappear.
5. Pressing the down arrow key select “GROUP”
6. Press “?”. The display will show ?, which means parameter value editting function
is on.
7. Using the arrow keys select appropriate parameter in the group.
8. Press “?”. ? will disappear.
9. Using the arrow keys access the parameter you want to change.
10.Press “?”. ? will appear before the parameter value on the display.
11.Change the parameter value using the arrow keys.
12.Leave the editing mode by pressing “?”. “?” will disappear.
The arrow keys are used to scroll the list of parameters. It is not necessary to enter
the code again before changing another parameter. However, if for 4 minutes no key is
pressed, the code returns to 100 and the code must be re-enetered before another param-
eter can be changed.
Changes in the parameter values are automatically saved in the memory and do not
need to be accepted. The set values are stored in the controller’s memory for at least 10
years (with a switched-off controller).

Str. 11
5LIST OF PARAMETERS:
NOTE: Inappropriate parameter settings may result in faulty boiler operation and in extreme
situations, in boiler failure.
When the power supply is on, the display will show information on the measured boiler
temperature, set temperature and the current operating mode. Using the arrow keys you
can view the measured temperature readings in the following order:
Controller operation mode, boiler measured temperature and
set temperature readings
Mode: OPERATION
Tch:55°C Tset:56°C
Outdoor temperature reading and information on the heating
season. “YES” will display if the boiler or mixer operate ac-
cording to the weather characteristics and outdoor tempera-
ture is lower than the shut down outdoor temperature
T ext. 10.0°C
Heat. season YES
Mixer temperature (set and measured) Mixer status:
M+opening, M0 inert, M- closing. PM – mixer pump status.
Mixer: 0 PM:0
Tm: 35°C Tms: 26°C
Measured and set hot water tank temperature.
T HW: 35°C
T HW set: 43°C
Measured feeder temperature.
T feeder: 65°C
Current time
Day: Tuesday
Time: 12:30:24
Parameter access code. In order to edit the parameters en-
ter 99.
CODE
100
Selecting a parameter group to be accessed for viewing and
editting. In order to change the parameter group press “?”
and use the arrow keys to select the desired group of param-
eters.
GROUP 1
Boiler param.
GROUP 1 – boiler parameters – accessible with user code 99
Desired blower speed setting (Setting range: 5 to 100%,
step 1%)
BLOWER
speed 70%
Feeder operating time in the OPERATION mode (Setting
range: 2 to 500s, step 2s).
t0:FeederOp. Time
OPERATION 5s

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Coal feeding break time in the OPERATION mode (Setting
range: 2 to 500s, step 2s).
t1:FeederBr. Time
OPERATION 30s
Feeder operating time in the MAINTENANCE mode (Setting
range: 2 to 500s, step 2s).
t2:FeederOp. Time
MAINTENANCE 5s
Coal feeding break time in the MAINTENANCE mode (Set-
ting range: 1 to 250min, step 1min).
t3:FeederBr. Time
MAINTENANCE 20min
Blower operating time after feeder is off (Setting time: 2 to
500s, step 2s).
t4:Blower oper.
time 20s
Blower operating time in the blow-through mode (Setting
range: 5 to 1250s, step 5s).
t5:Blow-through
time 5s
Feeder temperature limit, exceeding of which results in emer-
gency EMERGENCY SITUATIONS (Setting range: 0 to 99°C,
step 1°C).
Feeder maximum
temp. 80°C
C.H. circulation (directly from the boiler):
without timer – set temperature for the CH circulation is
obtained only from selected weather characteristics.
with timer – set temperature is adjusted by timer settings
reduction – set temperature is lowered by CH reduction pa-
rameter value
STOP – boiler pump (CH) is shut down. Set temperature
(boiler) drops to the temperature set for the mixer +
5°C (but not lower than boiler minimum temperature).
C.H. Operation
with timer
GROUP 2 – C.H. settings – accessible with user code 99
CH boiler set temperature at constant temperature value –
parameter visible only in CONSTANS mode (Setting range:
0 to 90°C, step 1°C).
Set temp.
C.H. 50°C
CH boiler set temperature at outdoor temperature +10°C –
parameter visible only in weather-dependent operation mode
(Setting range: 0 to 90°C, step 1°C).
At T ext = +10°C
Tch set = 50°C
CH boiler set temperature at outdoor temperature 0°C – pa-
rameter visible only in weather-dependent operation mode
(Setting range: 0 to 90°C, step 1°C).
At T ext = 0°C
Tch set = 50°C

Str. 13
CH boiler set temperature at outdoor temperature -10°C –
parameter visible only in weather-dependent operation mode
(Setting range: 0 to 90°C, step 1°C).
At T ext = -10°C
Tch set = 50°C
CH boiler set temperature at outdoor temperature -20°C –
parameter visible only in weather-dependent operation mode
(Setting range: 0 to 90°C, step 1°C).
At T ext = -20°C
Tch set = 50°C
The value by which boiler set temperature will be lowered
after thermostat input terminal has been opened (Setting
range: 0 to 50°C, step 1°C).
Boiler reduction
10°C
------------------------ CH circulation timer (boiler) ---------------------
Zone A start time on weekdays for CH boiler
Mon-Fri.CH.ZoneA
start 06:00
Set temperature adjustment for zone A on weekdays for CH
boiler (-40 to +40 °C).
Mon-Fri.CH.ZoneA
adjustment 0°C
Other zones for weekdays (including D) and appropriate adjustments are set in the same
way as for zone A.
Zone A start time on Saturdays and Sundays.
Sat/Sun.CH.ZoneA
start 08:00
Set temperature adjustment for zone A on Saturdays and
Sundays for CH boiler (-40 to +40 °C).
Sat/Sun.CH.ZoneA
adjustment 0°C
Other zones for Saturday and Sunday (including D) and appropriate adjustments are set in
the same way as for zone A.
NOTE!!! If a zone is not used it should be disabled by setting the time at —:—. It is displayed
after 23:50. A, B, C and D zones must appear sequentially after one another.
GROUP 3 – mixer settings accessible with user code 99
Mixer circulation:
without timer - set temperature for the mixer is obtained
only from weather characteristics.
with timer – set temperature is adjusted by timer settings
reduction – set temperature is lowered by mixer reduction
parameter value
STOP – mixer pump is switched off. Set temperature drops
to 0°C.
NOTE!!! If there is no mixer, mixer operating mode in the
control unit should be switched to STOP.
Mixer operation
with timer

Str. 14
Mixer set temperature at constant temperature value - pa-
rameter visible only in CONSTANS mode (Setting range: 0
to 90°C, step 1°C).
Mixer set temp.
30°C
Mixer set temperature at outdoor temperature +10°C – pa-
rameter visible only in weather-dependent operation mode
(Setting range: 0 to 90°C, step 1°C).
At T ext = +10°C
Tmix. set = 35°C
Mixer set temperature at outdoor temperature 0°C – param-
eter visible only in weather-dependent operation mode (Set-
ting range: 0 to 90°C, step 1°C).
At T ext = 0°C
Tmix. set = 35°C
Mixer set temperature at outdoor temperature -10°C – pa-
rameter visible only in weather-dependent operation mode
(Setting range: 0 to 90°C, step 1°C).
At T ext = -10°C
Tmix. set = 35°C
Mixer set temperature at outdoor temperature -20°C – pa-
rameter visible only in weather-dependent operation mode
(Setting range: 0 to 90°C, step 1°C).
At T ext = -20°C
Tmix. set = 35°C
The value by which mixer set temperature will be lowered
after thermostat input terminal has been opened (Setting
range: 0 to 50°C, step 1°C).
Mixer reduction
8°C
Mixer dynamics. Parameter determining valve response time.
The value selected should be suitable for controls require-
ments. (Setting range: 1 to 30, step 1).
Mixer Dynamics
6
------------------------ Mixer timer ---------------------
Zone A start time on weekdays for mixer
Mon-Fri.MixZoneA
start 06:00
Set temperature adjustment for zone A on weekdays for mixer
(-40 to +40 °C)
Mon-Fri.MixZoneA
adjustment 0°C
Zone A start time on Saturdays and Sundays
Sat/Sun.MixZone A
start 8:00
Set temperature adjustment for zone A on Saturdays and
Sundays for mixer (-40 to +40 °C)
Sat/Sun.MixZone A
adjustment 0°C
Other zones for weekdays (including D) and appropriate adjustments are set in
the same way as for zone A
Other zones for Saturday and Sunday (including D) and appropriate adjustments are set in
the same way as for zone A. NOTE!!! If a zone is not used it should be disabled by setting
the time at --:--. It is displayed after 23:50. A, B, C and D zones must appear sequentially
after one another.

Str. 15
GROUP 4 – DHW tank settings accessible with user code
DHW tank operation:
without timer – DHW set temperature is determined by “T
dhw set” parameter.
with timer – set temperature is adjusted by timer settings
reduction – set temperature is lowered by DHW reduction
parameter value
STOP – DHW circulation is off.
DHW operation
with timer
DHW tank set temperature (Setting range: 0 to 80°C,
step 1°C).
T DHW set
50°C
The value by which DHW tank set temperature is lowered by
the timer (Setting range: 0 to 80°C, step 1°C).
T DHW reduction
10°C
Zone A start time on weekdays (reduction start time) – DHW
operation with reduced temperature
Mon-Fri.HW ZoneA
Start Red. 08:00
Zone A end time on weekdays (reduction end time) – DHW
operation with set temperature
Mon-Fri.HW ZoneA
Stop Red. 14:00
Zone B start time on weekdays – DHW operation with set
temperature
Mon-Fri.HW ZoneB
Start Red. 22:00
Zone B end time on weekdays – DHW operation with tem-
perature lowered by DHW reduction
Mon-Fri.HW ZoneB
Stop Red. 6:00
Sat/Sun.HW ZoneA
Start Red. 08:00
Sat/Sun.HW ZoneA
Stop Red. 14:00
Sat/Sun.HW ZoneB
Start Red. 22:00
Sat/Sun.HW ZoneB
Stop Red. 6:00
Zone A start time onSaturdays and Sundays (reduction start
time) – DHW operation with reduced temperature
Zone A end time on Saturdays and Sundays (reduction end
time) – DHW operation with set temperature
Zone B start time on Saturdays and Sundays – DHW opera-
tion with set temperature
Zone B end time on Saturdays and Sundays – DHW opera-
tion with temperature lowered by DHW reduction

Str. 16
GROUP 5 - SYSTEM accessible with user code 99
Minute setting.
Minutes
30
Current hour setting.
Hours:
12
Current day setting.
Day:
Tuesday
Outdoor temperature, the exceeding of which by 2°C results
in switching off weather-dependent circulations (CH or mixer).
Heating is resumed when T ext drops below the value (Set-
ting range: 0 to 40°C, step 1°C).
Shut Down outdoor
temp. 16°C
User interface language
Language:
ENGLISH
GROUP 6 - SERVIS accessible with SERVICE CODE !
CH operating mode: weather-dependent or at constant tem-
perature (CONSTANS)
CH operation
WEATHER DEPENDENT
Mixer operation mode: weather-dependent or with constant
temperature (CONSTANS)
Mixer operation
WEATHER DEPENDENT
Maximum mixer temperature to be obtained from the curve
(Setting range: 0 to 90°C, step 1°C).
Maximum mixer temp.
85°C
Set boiler temperature in DHW tank loading mode (Setting
range : 0 to 90°C, step 1°C).
Boiler Temp. to
DHW load 70°C
Amplitude of DHW tank loading pump (Setting range: 1 to
20°C, step 1°C).
DHW amplitude
4°C
0 – priority off
1 – priority on
DHW priority
1
Maximum boiler temperature to be obtained from the curve
or set manually (Setting range: 0 to 95°C, step 1°C).
Boiler maximum
temp. 85°C

Str. 17
Minimum boiler temperature to be obtained from the curve
or set manually (Setting range: 0 to 90°C, step 1°C).
Boiler minimum
temp. 42°C
Boiler switching amplitude between OPERATION and MAIN-
TENANCE modes (Setting range: 1 to 30°C, step 1°C).
Boiler amplitude
4°C
When boiler temperature drops below this value boiler shut
down time countdown begins (Setting range: 0 to 90°C,
step 1°C).
Boiler shut down
temp. 35°C
Time for which boiler temperature must be lower than shut
down temperature for the boiler to switch off (Setting range:
1 to 250min, step 1min).
Boiler shut down
delay 60min
Temperature the exceeding of which turns on CH pump, mixer
pump and DHW pump. Turning off the pump below this value
is to facilitate boiler heating above the dew point which re-
sults in longer boiler life (Setting range: 0 to 90°C, step 1°C).
Pumps turn-on
temp. 38°C
Time after which CH pump is shut down after room thermo-
stat input is open. While in “no shut down” mode the pump is
working independently of the thermostat.
(Setting range: 0 to 30min, step 1min).
CH pump overrun
time 2m
Time after which HW pump is shut down after the
HW tank loading is finished.
(Setting range: 0 to 1000s, step 1s).
HW pump overrun
time 2s
FACTORY DEFAULTS
If the control system operation is disturbed due to faulty settings it is possible to set default
parameters. To do this:
- set the code to 70
- press both arrow buttons simultaneously
The controller will remember the values given in the field next to parameter numbers.

Str. 18
6WIRING DIAGRAMS
65
4
3
12 7
BA
T1
9810
1211 13 15
14 16
T2
18
17 19 21
20 22
3031 29 2728 26 2425 233940 38 3637 35 3334 32
T5
T4 W2
T3
RS 485
W1
Display panel
connection
1, 2 - power supply 230 V~ (1 - L, 2 - N)
3, 4 - fuse - max. 6.4A quick-blow
5 - mixer closing
6 - mixer opening
7 - mixer N wire
8, 11 - mixer pump
9, 10 - emergency output (no-voltage)
12, 13 - DHW pump
14, 15 - CH pump (boiler)
16, 17 - blower and feeder safety device - max. 4A quick-blow, safety strobe device should
be connected in series
18, 19 - feeder
20, 21 - blower
40, 39 - T1 sensor – outdoor temperature
38, 37 - T2 sensor – mixer temperature
36, 35 - T3 sensor – boiler temperature
34, 33 - T4 sensor – DHW tank temperature
32, 31 - T5 sensor – feeder temperature
30, 29 - W1 – mixer thermostat
28, 27 - W2 – CH thermostat (boiler)
23, 24, 25, 26 - Interface for conneccting COMPIT room module

Str. 19
7MOUNTING
The control system consists of 2 modules: control panel and operating module E551. The
operating module is placed in a housing to be mounted on a 35 mm DIN rail and it has the
width of 9 S301 modules. The contour is presented in the drawing below:
59 mm
90 mm
45 mm
Display panel is fitted on the boiler with four metal screws. The size of the panel and the
position of mounting screws is presented below:

Str. 20
In order to install the panel, the following panel mounting hole should be cut:
MOUNTING HOLE
The control panel is connected with the operating module by means of a 20-wire cable
included in the set.
8CONNECTING SENSORS AND ON/OFF INPUTS:
R551 control system works with five sensors. Outdoor temperature and mixer sensors are
Pt1000 series sensors. They can be connected to the controller with a 30m long cable with
diameter from 0.5 mm2 to 1.5 mm2. Remember that connection resistance of 3.9 ohm
gives a 1°C reading error.
Boiler, feeder and DHW tank sensors are T2001 series water immersion sensors. It is pos-
sible to extend the sensor up to 30 cm using a 0.5mm2 to 1.5 mm2 cable. T2001 sensors
cannot be replaced with T1001, T1002 or T1006 sensors!
A minimum spacing of 30cm between the sensor cables and parallel live network cables
should be kept. A smaller spacing may result in unstable temperature readings.
When mounting the sensors it is important to ensure their good contact with the surface.
While fixing the boiler and DHW tank sensors fill the pocket with silicon thermal grease, if
possible. The sensor cannot come in contact with water! While mounting the feeder sensor,
apply thermal grease on the contact place of the sensor and the screw. The sensor should
be insulated if possible. The same rules apply while mounting a clamp-on sensor behind the
mixer. While mounting the outdoor sensor the following rules must be observed:
- mount the sensor 2 – 2.5 m above the ground level
- mount the sensor on the north or western-north wall
- mount the sensor at least 1.5m from windows and doors
- you mustn’t mount the sensor above windows or doors!
- the sensor should not be covered when fitted!
On/off input terminals (of room thermostats) may only be connected to no-voltage
contatcs. These could be contacts of a relay, bimetal thermostat or electronic room thermo-