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19
Commissioning - Page 19
FIG. 26 MAIN BURNER PRESSURES ADJUSTMENT
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. When the
pressure and rate are correct, replace the adjustment
screw cover.
Shut down the boiler remove the pressure gauge and refit
the screw in the test nipple ensuring that a gas tight seal is
made.
Remove the self-adhesive arrow from the inspection ticket
tied to the burner supply pipe and stick it to the Data Plate
inside the controls cover to indicate the appropriate burner
setting pressure.
Refit the controls cover, and secure with screw.
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 3, PILOT BURNER, Page
22.
Boiler Thermostat
At its minimum and maximum settings, the thermostat
should control the water flow temperature at approximately
55ºC-82ºC (130ºC-180ºF).
The thermostat has been calibrated by the makers and no
attempt should be made to re-calibrate it on site. Turn on
the boiler thermostat and ensure that the main burner is
alight. Turn the thermostat to the ‘O’ 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 preset 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 80ºC.
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 80ºC.
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. 2.
NOTE:
Interruption of the electrical supply to the boiler may
also cause the overheat limit thermostat to operate.
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.
External Controls
Check that any other external control connected in the
system, such as clocks and thermostats, control the boiler
as required.
User’s Instructions
A User’s Instructions leaflet is provided with this boiler but
the householder must have the operation of the boiler and
system explained by the Installer. The householder must
also be advised of the importance of annual servicing and
of the precautions necessary to prevent damage to the
system and building, in the event of the system remaining
out of commission in frost conditions.
