High & Low Combustion Setting Procedure; Gas Inlet Ptn; Pcb Fan Speed Jumper - Keston Celsius 25 Installation And Servicing Instructions

WD209/1/2000
10. HIGH & LOW COMBUSTION SETTING PROCEDURE
It is important that the combustion at both high and low fire is checked and
set when conducting any work on the combustion circuit, especially gas valve
replacement.
The procedure below details this setting using an electronic means of locking the
boiler on high or low fire rate. Where the instruction requires that the electrical
supply to the appliance is isolated, correct isolation procedures shall be followed.
Always verify safe electrical isolation before working on an appliance.
1. Electrically isolate the appliance, verify that the electrical supply has been isolated then
removethe appliance case by first removing the securing screws at the top and bottom of
the appliance.
2. Once the casing has been removed
keeping your hands away from exposed
electrical components and connections,
switch the electrial power supply to the
appliance back on.
Prior to commencing the adjustment
procedure, the boiler should be brought
up to the normal working temperature, a
gas working pressure of at least 18mbar
should be present at the gas inlet test
nipple (see Figure 1) and the thin
neoprene plastic pipe between the
venturi and gas valve should be in
place/sound.
3. Turn off the boiler via the fascia control knob and electrically isolate the boiler. Verify
that the electrical supply has been
isolated.
4. The facia panel containing the on/off
knob should be removed via the four
retaining screws. Fascia PCB should
have the electrical lead still connected
and the knob left to the off position.
5. Please be aware that some of the
C25 boilers are fitted with a plastic
translucent moisture cover over the top
of the gas valve, this cover is held in
place by a Phillips screw on the gas
valve. Prior to adjustment this shield
should be removed.
6. On the right hand board as you look at the boiler face on, you will locate a small
electrical bridging jumper attached to the board. The jumper is red in colour, approx
18mm in from the front edge and 12mm up from the bottom edge of the board (see
Figure 2).
Installation & Servicing Instructions
Chapter 10 : Setting Procedure The Keston Celsius 25 & 25P

Gas Inlet PTN

Figure 1 - Gas Inlet PTN
Figure 2 - PCB Fan Speed Jumper
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