23
Fig. 29
7.3.6 FAN SPEED TABLE
Use the following table to set the corresponding fan speeds
that are relative to the appliance you are working on.
FAN SPEED (rpm) TABLE
MODEL
MAX
MIN
HTG
IGN
20HE
5.400
1.700
5.400
3.700
7.3 APPLIANCE FAN SPEEDS
The appliance fan speeds require to be checked and/or
adjusted prior to making any adjustments to the gas valve
or if the main PCB has been replaced.
ATTENTION
Gas type and appliance fan speed (output)
must be set
according to the specific appliance specification. Vokera
accepts no responsibility if the gas type and/or fan speed
is not correctly adjusted according to the respective
appliance specification as detailed on the appliance data
badge.
7.3.1 CHECKING/ADJUSTING THE APPLIANCE FAN
SPEEDS
Move the selector switch to the OFF position and remove
the 3-selector knobs.
7.3.2 ABSOLUTE MAX FAN SPEED
Locate the MAX trimmer (fig. 29) and gently adjust
clockwise or counter clockwise to achieve the correct fan
speed (see table 7.3.6). NOTE, the display shows the fan
RPM in multiples of 100, i.e. 25 = 2500RPM.
7.3.3 ABSOLUTE MIN FAN SPEED
Locate the MIN trimmer (fig. 36) and gently adjust
clockwise or counter clockwise to achieve the correct fan
speed (see table 7.3.6). NOTE, the display shows the fan
RPM in multiples of 100, i.e. 25 = 2500RPM.
7.3.4 IGNITION FAN SPEED
Locate the IGN trimmer (fig. 29) and gently adjust
clockwise or counter clockwise to achieve the correct fan
speed (see table 7.3.6). NOTE, the display shows the fan
RPM in multiples of 100, i.e. 25 = 2500RPM.
7.3.5 HEATING FAN SPEED
Locate the HTG trimmer (fig. 29) and gently adjust
clockwise or counter clockwise to achieve the correct fan
speed (see table 7.3.6). NOTE, the display shows the fan
RPM in multiples of 100, i.e. 25 = 2500RPM.
7.4 CHECKING THE CO
2
AND ADJUSTING THE GAS
VALVE
THE GAS VALVE MUST BE SET-UP OR ADJUSTED
WITH THE AID OF A PROPERLY CALIBRATED FLUE
GAS ANALYSER.
Isolate the appliance from the electrical supply and remove
the appliance casing as described in 4.7.1. Set the flue gas
analyser to read CO
2
and insert the probe into the flue
analysis test point (
A, B
fig. 28). Restore the electrical
supply to the boiler and switch the boiler to the OFF mode.
To adjust the gas valve you must first ensure that the fan
Fig. 30
Maximum
screw
Minimum
screw
Compensation
pipe connection
7.4.2 GAS VALVE MINIMUM SETTING
Locate and gently turn the HTG trimmer till the minimum
value (fan speed) is obtained and check that it corresponds
with the appropriate CO
2
value (Minimum) for the respective
appliance. If the CO
2
reading is correct, rotate the HTG
trimmer until the correct value is obtained for the respective
appliance (see fan speed table) and proceed to 7.4.3.
However, if the CO
2
reading is incorrect, the minimum gas
pressure must be adjusted as follows:
•
Using a 2,5mm Allen key, very slowly turn the minimum
adjustment screw (see fig. 30) – clockwise to increase,
counter clockwise to decrease - until the correct value is
displayed on the CO
2
analyser (allow time for the
analyser to stabilise).
7.4.3 COMPLETION
On completion of the combustion analysis check and/or
any gas valve adjustment, set the HTG trimmer to the
corresponding value as detailed in the fan speed table.
Refit the 3-selector knobs and move the mode selector to
the OFF position. Remove the test probe from the test
point and refit the sealing screw/s and/or cap.
IMPORTANT
A GAS SOUNDNESS CHECK MUST BE CARRIED OUT
IF ANY GAS CARRYING COMPONENTS HAVE BEEN
REMOVED, REPLACED, OR DISTURBED.
speed potentiometers (trimmers) have been set correctly
(see 7.3).
When carrying out a combustion analysis test and/or
adjusting the gas valve, you must ensure that all radiators
and heating circuits are fully open in order to dissipate
heat.
Remove the 3-selector knobs, locate and press the CO
button (see fig. 29). The appliance will now operate in CO
mode for approximately 15-minutes (see 7.10).
7.4.1 GAS VALVE MAXIMUM SETTING
Locate and gently turn the HTG trimmer till the maximum
value (fan speed) is obtained and check that it corresponds
with the appropriate CO
2
value (Maximum) for the
respective appliance. If the CO
2
reading is correct, proceed
to gas valve minimum setting (7.4.2).
However, if the CO
2
reading is incorrect, the maximum gas
pressure must be adjusted as follows:
•
Using a suitable screwdriver, very slowly turn the
maximum adjustment screw (see fig. 30) – clockwise to
decrease, counter clockwise to increase – until the
correct value is displayed on the CO
2
analyser (allow
time for the analyser to stabilise).
UNUSED
