Kromschroder FCU 500 - Assignment of Connection Terminals

FCU 500, FCU 505 · Edition 02.17 17
Function
3.1.3 Assignment of connection terminals
Terminal Type Designation Function
1
24 V DC input
Start-up signal Signal applied: FCU start; no signal: FCU stop
2 Controlled air flow
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 (FCU start).
3 Remote reset Input for external signal (button) to reset the unit after a fault lock-out
4 Operating signal
Signal from the burner control units to inform the FCU that a sufficient number of burners is
available for temperature control
5, 6
and
7, 8
Double
thermocouple
Safety temperature monitor and/or
safety temperature limiter
Monitor the spontaneous ignition temperature of the gas/air mixture in High temperature
mode and/or the maximum furnace or flue gas temperature using the integrated
temperature module of the FCU..H1
11, 12 V AC input Supply voltage
Voltage to operate the FCU,
11 = phase (L1), 12 = neutral conductor (N)
13
Safety circuit output
Gas valve V1 Connection of phase for gas valve V1
14 Gas valve V2 Connection of phase for gas valve V2
15 Gas valve V3 Connection of phase for gas valve V3
57 Safety interlocks (limits) Safety enable signal to the burner control units
16 Safety limits (limits during start-up)
To ensure that the correct air volume is available for ignition (start fuel flow rate) when
starting the burners, the FCU sends the burner start enable signal to the burner control
units via this output.
17 Purge Signal to FCU 505 or burner control units to inform them that purge is in process
18 High temperature operation Enable signal from the FCU indicating that the furnace system is in High temperature mode
41
24 V DC output
Fault Fault signalling output, 24 V DC, max. 0.1 A
42 Operating signal Operation signalling output, 24 V DC, max. 0.1 A
44 24 V DC input Fan ready for operation Feedback signal from fan indicating readiness for operation, see Parameter 31
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