Assignment Of Connection Terminals - Honeywell BCU 370 Technical Information

Function

3 .1 .5 Assignment of connection terminals

Terminal Type
1, 2 V AC input
3 V AC output
4
Safety circuit
5
output
6
7
Inputs for
9
pressure switches
11
8, 10 and
V AC outputs
12
13
14
Flame control
15
16
17, 18 1) 2)
Floating contact
19, 20 1) 2)
21 1) 2)
22 1) 2)
V AC input
23 1) 2)
24
25 2)
Connection for
external three-
26 2)
point step
27 2)
controller
28 2)
▼
BCU 370 · Edition 01.19
Designation
Supply voltage
Fan
Gas valve V1
Gas valve V2
Gas valve V3
Minimum air pressure
Minimum gas pressure
Maximum gas pressure
Mains supply
Flame amplifier input
Supply voltage to UV sensor
Burner ground
Ignition transformer output
Signalling contact for operating
signals
Signalling contact for faults
Start-up signal
Controlled air flow
Remote reset
Controller enable/emergency stop Connection for higher-level safety devices and interlocks (e.g. emergency stop)
Controller enable
Y- (to ignition position)
Y- (to min. position)
Y+ (to max. position)
Function
Voltage to operate the BCU,
1 = phase (L1), 2 = neutral conductor (N)
Connection for fan control
Connection of phase for gas valve V1
Connection of phase for gas valve V2
Connection of phase for gas valve V3
Connection for pressure switch to monitor the minimum air pressure
Connection for pressure switch to monitor the minimum gas pressure
Connection for pressure switch to monitor the maximum gas pressure
Phase for pressure switch mains supply
Input for flame amplifier
Output for supply voltage to UV sensor
Burner ground input for UV sensor
Output for (external) ignition transformer
Contact between terminals 17 and 18 closes once the operating signal has been
received from the burner
Contact between terminals 19 and 20 closes in the event of a BCU fault signal
Signal applied: BCU start; no signal: BCU stop
Signal applied: fan is started to supply air to the combustion chamber for cooling, for
example. Only functional in standby. The function is deactivated as soon as a signal is
received at terminal 1 (BCU start).
Input for external signal (button) to reset the unit after a fault lock-out
Output signal for controller enable for the three-point step controller. The actuator can
be set to various positions.
Connection for the signal to activate the ignition position
Connection for the signal to activate the position for minimum capacity
Connection for the signal to activate the position for maximum capacity
17