Air Valve Control On Bcu; Purge; Cooling In Start-Up Position/Standby; Burner Start - Honeywell Krom Schroeder BCU 480 Manual

Parameters
4 . 7 Air valve control on BCU . .L
Parameter 30, Behaviour of the air valve during opera-
tion.
Parameter 31, Behaviour of the air valve during start-up.
Parameter 32, Behaviour of the air valve in the event of
a fault lock-out.
The BCU..L features an adjustable air valve control. The
display shows that purging is currently being carried
P 0 A
out with . indicates that the air valve is being ac-
tivated for cooling or heating.
The BCU..L supports the following functions:

– Purge

– Cooling in start-up position/standby

– Switching of the burner between low and high burner
capacity during operation via the air valve
– To start up the burner as intended, external activation
of the air valve can be blocked during start-up (pre-
vents synchronization problems between the BCU
and the central control system).
– Setting the air valve parameters, so that it
– opens with valve V1
– opens with valve V2
– opens once the main burner has reached its operat-
ing position
– Low fire over-run time t
down
BCU 480 · Edition 03.16l
after a controlled shut-
KN
4 . 7 .1 Purge
In the case of multiple burner applications, burners with
mechanical combustion air supply are used. The air for
combustion and pre-purge is supplied by a central fan
controlled by a separate logic. This logic determines the
purging time.
The BCU..L..E1 with adapted power management sup-
ports centrally-controlled pre-purge or post-purge.
The BCU..L is informed that purging is currently being
performed by input 22. It then opens the air valve, re-
gardless of the status of the other inputs (purging has
priority). The display indicates
On BCUs without power management, input 22 and in-
put 5 (safety interlocks) must be activated for purging,
see connection diagrams on pages 14 (BCU 480), 16
(BCU 480..B1) and 18 (BCU 480..P with industrial plug
connector).
4 . 7 .2 Cooling in start-up position/standby
The air valve can be activated externally via input 23 for
cooling in the start-up position. During activation of the
air valve the display shows
currently being carried out.

4 . 7 .3 Burner start

Parameters 30 and 31 determine the behaviour of the
air valve during burner start.
P 0
.
A 0
, indicating that cooling is
48