Glow-worm cxi and Gas Valve - Manual (Page 30)

30 0020013349-02
11 Commissioning
11.3 Preparation for Lighting
Isolate the boiler from the mains electrical supply.
Test for gas soundness and purge air from the gas supply. Turn
on the gas service cock, see diagram 7.1.
11.4 Initial Lighting
The lighting procedure of the boiler is fully automated.
Check that all external controls are calling for heat. If the integral
programmer is fitted check that it is correctly programmed and
if necessary overridden to provide heat.
Ensure that both the central heating water temperature and the
hot water temperature control knobs are turned OFF (0).
Turn on the mains electrical supply and the mains reset knob to
(I) on the controls fascia.
Turn the central heating water temperature control knob to (I)
MINIMUM.
The digital display will show water temperature in central
heating demand.
The fan should start and after a few seconds the ignition will
commence
If the burner fails to light the fan will stop. Initially this may be due
to air in the gas supply line. The boiler will automatically have
three attempts at ignition.
If necessary turn the reset switch to the off position (0), then
back to the on position (I) and the boiler will restart.
After the boiler has lit, allow to warm at MINIMUM temperature
setting to purge any air from the system.
NOTE: If the appliance is operated above MINIMUM on initial
lighting, there is a possibility that the overheat thermostat will
trip and "F5" will be displayed on controls fascia, this is due to
air not having been completly purged. See diagram 11.3 for
reset switch.
Once the system has been purged of air turn the Hot water
temperature control knob to the desired position and open a hot
water tap. The diverter valve motor will move to hot water supply
and the display will read system pressure. Check that hot water
is available and then close the hot water tap.
Turn the Central heating water temperature control knob to the
desired temperature.
The appliance will then continue to fire in central heating until
the user controls are satisfied or there is another demand made
for hot water.
NOTE: After first power up the firing sequence for central
heating changes. After one minute stabilisation time the boiler
will ramp slowly to full rate rather than going immediately to full
rate. This is an adaptive feature to cope with small system
requirements.
Diagram 11.4
ELECTRICAL
PLUG
GAS
VALVE
INLET PRESSURE
TEST POINT
12402
Diagram 11.3
OVERHEAT
THERMOSTAT
RESET
SWITCH
THROTTLE
OFFSET
ADJUSTMENT
11.5 Testing - Natural Gas ONLY
Should any doubt exist about the gas rate, check it using the
gas meter test dial and stop watch at least 10 minutes after the
burner has lit, making sure that all other gas burning appliances
and pilot lights are off.
The approximate gas rates: 24cxi : 2.24m 3 /h (79ft 3 /h)
30cxi : 2.8m 3 /h (99ft 3 /h)
38cxi : 3.6m 3 /h (127ft 3 /h)
The gas valve is factory set for natural gas (G20) and should
need no adjustment. (LPG (G31) should be adjusted as described
on the previous page). It should be checked that the supply
pressure is 20mbar when the boiler is firing at full rate. This can
be achieved by turning on several hot water taps and checking
the inlet pressure at the inlet pressure test point on the gas valve
shown in diagram 11.4. Turn taps off and disconnect pressure
gauge.
In the unlikely event that the gas valve needs adjusting, refer to
section 12.6. Re-setting of the gas valve requires a combustion
analyser and any adjustment should only be carried out by a
competent person.
Note that the burner pressure cannot be measured at the gas
valve as it is altered by the suction of the fan and modulated
according to demand.
11.6 Testing - Heating System
Check that all remote controls are calling for heat. The boiler will
fire automatically. Fully open all radiator valves, flow control
valve 'A', if fitted, see diagram 4.1.
Balance the radiators as required and if fitted adjust valve 'A' to
give the required system differential. Turn off all radiators that
can be shut off by the user and check to see if less than the
maximum differential allowed of 20
o C can be achieved across
flow and return.
This boiler has a built in bypass, see diagram 11.5.
The boiler is supplied with the bypass open half a turn. It should
not be necessary to adjust the bypass, but if required turn the
adjustment screw clockwise to close the valve, see diagram
11.5.
Allow the system to reach maximum temperature then switch
off the boiler by isolating from the electrical supply.
Drain the entire system rapidly whilst hot, using the drain tap at
the lowest part of the system. Fill and vent the system as
described previously in section 11.2.
Lock or remove the handle from control valve 'A', if fitted.
Replace inner casing panel and front casing panel.