46
Installation and Servicing
SECTION 3 - SERVICING
3.19 PCB REPLACEMENT
CENTRAL HEATING CIRCUIT
1.
Refer to Section 3.9.
2.
Close all the CH water isolating valves on the
boiler inlet.
3.
To drain the primary heat exchanger circuit:
Open the drain valve and attach a length of hose
to the CH drain point.
4.
After replacing any component on the boiler,
remove the hose, close the drain valve and
open all system isolating valves (re-pressurise
as appropriate) before proceeding to check
operation of the boiler.
5.
Check operation of the boiler. Refer to Sections
2.25 & 2.26.
CH
Circuit
Drain
3.20 DRAINING THE BOILER
Note.
Fit the earth strap provided with the PCB to your wrist and
secure to a suitable earth on the boiler chassis.
1.
Refer to Section 3.9.
2.
Ensure the control knobs are in the 12 o clock position.
3.
Carefully release the six retaining clips and remove control
box cover.
4.
Unplug all lead connections to the PCB.
5.
Remove the 2 screws, if applicable.
6.
Spring out the four side retaining clips and pull the PCB
upwards to clear the corner retaining posts.
7.
Take the new PCB.
8.
Re-connect all plug connections.
9.
Reassemble in reverse order.
10.
a. Turn power on, display shows uP.
Rotate both dials fully
anti-clockwise.
b. Press
RESTART, display shows oF
c. Turn power off
d. Turn power on, display shows F9
e. Using central heating knob, rotate clockwise or
anticlockwise to show “Su” for System, then press
RESTART button.
f. Using central heating knob, rotate clockwise or
anticlockwise to show “n” for Natural Gas, then press
restart button.
g. Using central heating knob rotate clockwise or
anticlockwise to show boiler size, select correct 18 or 30,
then press RESTART button.
h. Display shows “Su”, “n”, Boiler size, internal number.
j. Press restart. New PCB is now programmed.
11.
Check that the boiler operates in both DHW and CH modes.
3
IMPORTANT.
IT IS CRITICAL FOR SAFE
OPERATION THAT THE CORRECT BOILER SIZE
AND FUEL TYPE IS ENTERED INTO THE BOILER.
SER
VICING SER
VICING
6
4
4
5
5
Summary of Contents for LOGIC+ SYSTEM S18
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