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Once the heat exchanger has been suitably cooled (temperature
measured by the SR heating circuit probe lower than the T

re-

ignition temperature), the system can start operating normally
again.

Destratification gradient

Spacious rooms can be subject to air stratification phenomena: hot
air tends to rise above creating a considerable temperature
difference between the comfort zone and the room ceiling.

Higher temperature

Lower temperature

Comfort zone

Fig. 7 – Air stratification phenomenon

If the hot air generator is installed in a high position and an SA
local room temperature probe is used, the following directions will
have to be observed for a correct room temperature adjustment:

1) place the SA probe next to the comfort zone for a correct

room temperature detection (fig. 8a), or

2) use the

destratification gradient (0

10°C), which will be

deducted from the temperature measured where the hot
air generator is installed in order to calculate the
temperature of the comfort zone (fig. 8b).

Comfort zone

Generator

Probe (SA)

Comfort zone

Generator

Probe (SA)

Destratification
gradient

Fig. 8 – Solutions for a correct temperature adjustment

The destratification gradient factory setting is zero (0°C): different
parameter values can be set up on request.

!!!!

IMPORTANT NOTE
This parameter can be modified through BRAHMA serial interface type 810 and
management software.

Outside temperature probe function

As already mentioned before, the outside ambient temperature can
contribute  to  the  system  temperature  adjustment  process:  in  fact,
through a remote controller it is possible to reserve the SA input of
the  control  unit  no.  "n"  (in  case  of  a  cascade  system)  to  this
function,  enabling  all  units  to  adjust  the  modulation  power
according to the outside temperature measured.

TC340(P1) - OPERATION
In  this  case,  the  device  is  used  for  the  ignition,  the  flame  control
and  (if  available)  the  modulation  of  premix  burners  equipped  with
fan with PWM control.
To  better  understand  the  operation  of  the  system,  please  refer  to
the operating cycle diagrams in the next pages.
At  the  first  start-up,  the  device  is  in  stand-by  status  and  the  fan
control is disabled (point 1).
In case of heat demand (TC boiler thermostat closing, point 2), the
device  performs  the  start-up  cycle,  carrying  out  the  TP  pre-purge
time  at  TP1_speed  and  then  the  TP2  second  pre-purge  time  and
the TS safety time at start-up speed (TP2_TS_speed, point 3).
In  case  of  flame  signal  failure  at  the  end  of  the  safety  time,  the
system goes to lockout; else, the system goes on (point 4) carrying
out  the  modulation  delay  time  lasting  for  DELAY_RP_STAB  at
RP_STAB_speed in order to settle the burner flame.
At  the  end  of  this  phase  (which  can  be  set  up  to  "0"  if  it  is  not
necessary),  the  device  enters  the  real  operation  stage  (point  5,
running position), setting up the fan speed to the RP_speed value,
which  can  be  increased  (point  7)  or  decreased  (point  9)
dynamically through the IN(+) and IN(-) adjustment inputs within a
range  limited  by  the  RP_MAX_speed  and  RP_MIN_speed  values
(as  soon  as  these  two  values  are  reached,  as  shown  on  points  8
and 10, the adjustment inputs do not affect the PWM output signal
value).
In running status, the output modulation power can be increased to
a  predetermined  RP_T2_speed  value  by  means  of  the  T2
adjustment input (point 6): this function can be used if the burner is
provided with two flame stages or if you wish to obtain a temporary
modulation “boost”.
As soon as the heat demand stops (point 11), during operation the
system can:

−

go to stand-by position;

−

proceed to post-purge at POST_speed (in case of option P or

PT).

The  following  table  shows  the  modulation  parameters  of  the
device, which can be pre-set and modified through serial interface.
Upon  request  it  is  possible  to  mount  a  vertical  module  with
microcontroller  technology  which  enables  to  set  up  three  of  the
above-mentioned modulation parameters through a trimmer; these
parameters  can  be  factory-set  and  can  be modified  through  serial
interface and management software.

No.

Parameter

Range

Description

TP1_speed

100 %

PWM percentage during the first pre-purge time (TP1)

TP2_TS_speed

100 %

PWM percentage during the second pre-purge time (TP2) and the safety time (TS)

RP_STAB_speed

100 %