Publication No. 5105703
22 Commissioning
Refer to Fault Finding Chart Fig. 31
Turn the boiler thermostat on and to a high setting and
after a period of time the main burner will light, this can
be observed through the sight glass in the front cover of
the boiler. The time period can vary upwards of 45
seconds, depending on the amount of air in the pipework.
Test for gas soundness around the boiler components
using leak detection fluid.
Turn the boiler thermostat to ‘0’. Note: There could be a
delay in lighting if the control knob is switched on and off
and then on again rapidly.
Setting and Checking of Controls
With the controls cover removed.
Fit a pressure gauge to the pressure test nipple in burner
supply pipe. See Fig. 1.
Turn on the boiler thermostat and ensure that the main
burner is alight. Check that the burner pressure is in
accordance with values stated on the Data Badge.
The gas valve is factory set, but if adjustment is required
follow section 4.8.
With the burner set to its correct pressure, the firing rate
given in Technical Data should also be obtained and
this should be checked by meter reading at least 10
minutes after the main burner has been lit.
Shut down the boiler, remove the pressure gauge and
refit the screw in the test nipple ensuring that a tight seal
is made.
Refit the controls cover.
Relight the boiler and heat the system to maximum.
Check for water leaks, turn the boiler off, drain the
system whilst hot.
Refill the system and on sealed systems adjust to the
correct cold fill pressure. Set the pressure gauge pointer
to the system design pressure.
If a by-pass circuit is fitted the by-pass valve should be
adjusted with the boiler operating under minimum load
conditions to maintain sufficient water flow through the
boiler to ensure that the overheat thermostat does not
operate under normal operating conditions.
Pilot Burner
The pilot is pre-set and no adjustment is required. The
pilot flame envelope should cover the electrode tip and
spark earthing strip, see Fig. 30. If the pilot flame is not
as illustrated, remove and clean the pilot as described
in the Servicing Instructions Section 4.3, Pilot Burner,
Page 26.
Boiler Thermostat
At its minimum and maximum settings, the thermostat
should control the water flow temperature at approximately
55 °C - 82 °C (130 °F - 180 °F).
The thermostat has been calibrated by the makers and
no attempt should be made to re-calibrate it on site. Turn
the thermostat to the ‘0’ position and check that the main
burner shuts down.
Gravity Hot Water/Pump Over-Run Thermostat
The function of this thermostat is determined by the
position in which the GRAVITY/FULLY PUMPED
SYSTEM selection switch is set. The thermostat is pre-
set and no adjustment is possible.
On the FULLY PUMPED switch position it will operate
as a pump over-run thermostat and will keep the pump
running after the boiler has shut down, as long as the
water temperature within the boiler is above approximately
80 °C.
On the GRAVITY switch position it will operate in series
with the boiler thermostat when only the gravity domestic
hot water circuit is in operation.
It will over-ride the boiler thermostat when the water
temperature within the boiler is above 80 °C.
Overheat Thermostat
The overheat thermostat is pre-set and no adjustment is
possible. It will require manually resetting if an overheat
condition occurs. Access to the reset button is through
a hole in the underside of the controls cover, see Fig. 1.
Other Boiler Controls
All boiler mounted controls are designed so that if any
fault should occur they will fail safe. No further setting
or checking is necessary.