Glow-worm hxi and Gas Valve - Manual (Page 47)

LPG MODELS - ONLY
Refer to diagram 2 and turn the gas valve throttle
fully clockwise, then turn the throttle anti-clockwise by the
number of turns shown in the table on the back page.
Please refer to the specific instruction relating to your
model.
1. Turn on the electrical supply.
2. Ensure external controls are calling for heat.
3. Turn on the gas supply.
4. Turn on the appliance.
5. The boiler should fire automatically.
NOTE: LPG MODELS
If the appliance does not light & goes to lockout (F1), turn
the throttle anti-clockwise 1 full turn. Reset the appliance.
The appliance will (after a short delay) again attempt to
fire. If necessary, repeat this procedure up to a total of 2
extra turns on the throttle screw, until the appliance lights.
Several ignition attempts may be needed, to purge gas
through the appliance, before a successful ignition is
achieved.
ALL MODELS
With the appliance cold.
Connect a CO2 combustion analyser to the appropriate
test point, see diagrams 1.
Maximum Rate Check and Adjustment
Refer to the instructions supplied with your appliance and set the
maximum rate.
Check and adjust CO2 as necessary.
NOTE: Adjustment is made by turning the throttle an
⅛ of a turn, waiting 1 minute to allow the appliance
to stabilise before checking or making further
adjustments.
● Rotate the “throttle”(anti-clockwise to increase), to the
required CO2, refer to diagram 2 and the “SETTING”
column in the table.
● Now proceed to check the minimum rate adjustment.
Set appliance to minimum rate.
Minimum Rate Check and Adjustment
Refer to the instructions supplied with your appliance and set the
minimum rate.
Check and adjust CO2 as necessary.
Adjustment is made by turning the offset adjustment, see
diagram 2.
If adjustment is necessary, proceed as follows:
NOTE: Adjustment of the CO2 at minimum rate is very
coarse and should not be adjusted more than an ⅛ of
a turn at a time. Wait 1 minute to allow the appliance
to stabilise before checking or making further
adjustments.
● Gradually rotate the “offset adjustment” (anti-clockwise
to decrease) to the required CO2, refer to diagram 2 and
the “SETTING” column in the table.
Re-Check CO2 and check the CO/CO2
combustion ratio.
● Re-check the maximum and minimum CO2 values to
ensure that they are within the “setting” limits in the table
then check the CO/CO2 combustion ratio does not exceed
the value in the CO/CO2 column of the table. If the CO/
CO2 setting exceeds the value in the table, a complete
servicing of the appliance will be necessary, refer to the
servicing instructions
Check the Gas Inlet Pressure and Gas Rate
On completion, test the gas installation for tightness using
the pressure drop method and suitable leak detection fluid,
purge in accordance with the above standard.
NOTE: Due to the modulating operation of the boiler and
the need to check the gas inlet pressure and measure the
gas rate at maximum rate, it will be necessary to force it to
maximum.
Operational Gas Inlet Pressure
With ALL other gas appliances operating, check the
operational supply pressure at the gas service isolation
valve test point, refer to your Installation literature supplied
with your appliance.
The nominal supply pressure for Natural Gas (G20) is
20mbar.
The nominal supply pressure for LPG (G31) is 37mbar.
Turn the taps and appliances off, then disconnect the
pressure gauge.
Additionally the safe nominal maximum heat input of the
appliance can be achieved at an inlet pressure down to
15mbar.
NOTE: The BURNER PRESSURE cannot be measured
and is not used to measure the gas rate.
Gas Rate
Make sure that ALL other gas burning appliances and pilot
lights are off.
Check the gas rate using the gas meter test dial and stop
watch, at least 10 minutes after the burner has lit, see
table below for approximate rates.
In communal or LPG installations where the gas rate
cannot be measured it is acceptable to measure the
combustion rate as described in the servicing section.
On completion, reset the boiler to normal operation by
referring to the Installation and Servicing Instructions.
Completion
If it is not possible to achieve the required results for
either the combustion or gas rates, it will be necessary to
complete a full service of the appliance and then repeat
the combustion check procedure. If after servicing and
adjustment of the appliance the combustion values are still
unacceptable and after further remedial work has been
carried out, the appliance must be disconnected until the
CO/CO2 ratio is acceptable. Advice can be sought from
the Glow-worm Technical Helpline.