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EL.-control
Temperature range
selector
The A1 PC-board is supplied with 24V AC from the con ver ter PC-board A2, and it is controlling the oil
injection (Y1) into the boiler with a 24V sig nal of X2, 4 and 5. This on/off sig nal is e.g. con trol led by the
fl ow controllers B1 and B2, which are each equipped with a Reed switch making contact when there is
a fl ow through the mac hi ne.
If both fl ow controllers are not making contact at the same time (max. time dif fe ren ce approx. 4 sec.), the
signal for oil injection (Y1) will disconnect and close, until the machine is stopped and restarted.
The tem pe ra tu re regulation is getting in for ma ti on from the tem pe ra tu re sen sor B4 (PT500) placed in the
out let pipe from the boiler and from the adjustable po ten ti o me ter placed on the PC-board. The result is
to get her with B1 and B2 controlling the sig nal for oil injection (Y1).
A safety thermostat (priming safety) B7 is securing that the mac hi ne stops, if the tem pe ra tu re of the
boiler outlet pipe exceeds approx. 173°C. On some machines this additional safety is replaced by a
built-in resistance.
The fl ame su per vi si on circuit is connected to a light sensor B5 (X3.11 and X3.12) in the top of the boiler
and stops the machine under the following con dit ions:
a)
If a fl ame has not occured within 5-10 sec. after the thermostat out put has closed.
b)
If the fl ame disappears for more than 5-10 sec. while the thermostat output is closed.
c)
If the fl ame is present 15-30 sec after the thermostat output has opened.
d)
If a fl ame breaks out and stays for more than 15-30 sec. while the thermostat output is open.
e)
If the light sen sor is short-circuited or disconnected.
D_CON. 03GB.
A1
08
09
8 7 6 5 4 3 2 1
safe pump
12
B5
B7
Plug for test box no. 6420100, see page 32.
x2
oil
motor
24V
9
8
x3
B4
B2
B1
C
Function
x2
1
x3
15
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