Compit R551 User manual

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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

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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.

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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

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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

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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.

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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.

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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.

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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.

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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).