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Building Technologies CC1N7761en
HVAC Products 19.02.2007
Function (cont´d)
In principle, the program sequence is the same as with burner startup without ignition
spark proving.
Exceptions:
- If the UV flame detector does not receive any input signal during the short preigni-
tion time (UL2 on «Short preignition»), lockout occurs before any gas is released,
i.e. safety time TSA = 0 seconds
- With ignition spark proving, the safety time for the pilot burner can only be adjusted
between 0...6 seconds (in the time diagram of the programming mechanism: TSA´)
... after a controlled shutdown
Controlled shutdown occurs as soon as one one of the control or supervision devices in
the control loop between terminal 8 and 9 opens its contact. In that case, the fuel
valves will immediately be shut. The programming mechanism starts again and now
programs postpurging, if required. On completion of the postpurge time, the program-
ming mechanism has again reached its start position where it remains until the next
switch on command is received. The flame supervision restarts again during the post-
purge time. Therefore, any flame signal during that period of time will lead to lockout.
... after resetting the LEC1...
After pressing the built-in or the external lockout reset button, the programming mecha-
nism will return to its start position. The only burner plant component that is operated
during that period time is a fan motor connected to terminal 17. As the control thermo-
stat or pressurestat normally continues to call for heat, the programming mechanism
will initiate a restart after reaching the start position.
Program indicator
LANDIS & GYR
Type Serie ts s
V~ c/s Hz VA
4A
V~ 2A
3
5 6 7 101117202122
1
23
t1
A
B
C
D
E
G
= 8...63 s
(1)
7761z01/1102
40
30
The program indicator continuously shows the respective phase of the burner startup
sequence. The letters correspond to those of the programming mechanism diagram
next to the viewing window. The figures indicate the remaining prepurge time. If lock-
out occurs, the programming mechanism and the program indicator stop, thus indicat-
ing the operating phase during which lockout occurred.
Examples:
40
30
← Prepurge time will last another 35 seconds
Valve 2 at terminal 7 is opened →
D
F
E
Burner startup with
ignition spark proving
Control sequence...
Reading the program
indicator
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