Technical documentation
Technical documentation
STEM@ ed 06/01
23
EOLO MAIOR @
Central heating request with Remote Friendly Control (CAR)
If the conditions detected by the remote control (CAR) require operation in central-heating phase
(
SUM/WINT switch in WINTER position, request from time programmer, adjustment of room
temperature above that found
), the low-voltage circuit starts the circulator (M1) and powers the relay
K1.
If the contact of the system water pressure switch (S7) is closed and the temperature read by the NTC
central-heating sensor (B1) is below that set with the central-heating potentiometer of the remote control
(CAR), the low-voltage circuit excites the relay K2.
This results in the powering of the ignition unit (IGN. CARD) and starts the ignition cycle which
develops in the same way as the central-heating request with room thermostat.
During operation, the signal to the coil is changed in a way directly proportionate to the difference
between the temperature set with the central-heating potentiometer (C.H.) and that detected by the NTC
central-heating sensor (B1) and, if necessary, reaches the max figure set in 13.5 minutes
(max central-
heating output).
When the set temperature is exceeded, the contact of relay K2 is opened with the consequent switching
off of the burner. This cannot be started again for the same request for 180 s / 30 s.
Domestic hot water request
Once the d.h.w microswitch (S6) has been closed, burner ignition continues in the same way as in
heating.
During the first 5 seconds after the gas valve (Y1) has been engaged, power to the modulation coil is
restricted by the adjustment made using the soft ignition trimmer (IGN. POWER)
Subsequently, this power is increased so as to immediately achieve (
if requested
) the max set value.
During operation, modulation is performed with reference to the difference between the temperature set
using the d.h.w. potentiometer (D.H.W.) and the temperature read by the d.h.w. sensor (B2).
When the set temperature is reached, the burner is kept operating at minimum output and the contact of
relay K2 is opened (
burner switch-off
) when the d.h.w. sensor (B2) reads a temperature 5°C above that
requested.
It is closed again when the temperature drops by 1°C.
If, during operation, the central-heating sensor (B1) reads a temperature above 85°C, the contact of relay
K2 is opened. This is closed again as soon as the temperature drops back to 80°C.
NOTE
: the B&P modulation boards can be adjusted (
see d.h.w. modulation switch
) so that when the set
value is exceeded, the burner continues operating at minimum output and only switches off when the
d.h.w. sensor (B2) reads a temperature above 65 ºC .
The burner is switched back on when the temperature read by the d.h.w. sensor (B2) drops to 64 ºC .
Central-heating antifreeze request
When the temperature read by the NTC central-heating sensor (B1) drops below 4 ºC, the board gives
the ok for ignition and keeps the burner running at the output set by means of the minimum central-
heating output adjustment trimmer (C.H. MIN. POWER.) until a boiler temperature of 42°C is reached.
D.h.w. antifreeze request
When the temperature read by the NTC central-heating sensor (B1) drops below 4 ºC, the board gives
the ok for ignition and keeps the burner running at the output set by means of the minimum central-
heating output adjustment trimmer (C.H. MIN. POWER.) until the d.h.w. sensor reads a temperature of
8°C.
During operation, the water in the primary circuit is kept at a temperature below 42°C because when this
temperature is reached, the board switches off the burner.
