MBD200
8
14/02/04
Carry out electrical tests as stated in Electrical
Connections if not already done so.
With all valves fully open, and the filling loop con-
nected, fill from the mains supply, then follow the
procedure below.
Check for water soundness and rectify where neces-
sary.
Check that there is a leakfree working connection from
the boiler to the drain. The simplest way to do this is to
carefully pour some water into the boiler flue and
check it emerges at the drain.
DO NOT TURN ON GAS
Drain the system by opening all draincocks. This
will flush the system of flux and swarf.
Pour in all the inhibitor, and fill to required pressure
plus 0.3 bar to allow for venting.
Switch on the electrical supply to the boiler and
switch the Thermostat/Timeswitch ON.
Switch off after about five seconds and vent all
points again.
Repeat this for 5 minutes.
Re-pressurise if required.
Turn on pump (do not turn on gas) and run for at
least 30 minutes with all valves open.
Stop pump at five minute intervals and vent until no
more air can be removed and air noises are no
longer produced at the boiler. While the system is
venting check again for water soundness.
TURN ON THE GAS
Check for gas soundness (BS 6891) in pipework to
boiler using a manometer.
Select each boiler in turn, open the gas cock and
after purging the system, the boiler will light auto-
matically.
Run system at maximum thermostat setting.
Gas soundness within the boiler should be checked
using sense of smell and/or leak detection fluid.
Continue running for 15 minutes, venting every 5
minutes.
The Pilot is factory set.
The Main Gas Valve, GV2, gradually raises the
pressure to the set point. Allow at least 60 seconds
for the final pressure to stabilise.
IMPORTANT. It is essential when setting the
burner pressure that the inlet pressure is at
least 20 mbar (NG), 37 mbar (LPG) with the
boiler and any other connected appliances
running.
Set the burner pressures to the correct pressure by
using a manometer connected to the control and
adjusting the regulator to the desired input. (see the
charts below and Fig.1)
Low water content, fabricated boilers are vulnerable
to damage by air, particularly when the system water
is ‘hard’. (Contains a lot of dissolved calcium salts).
The result of this damage is evident in noisy boilers
and reduced service life.
Removal of air from a system mainly takes place
when the water is stopping, starting or not moving at
all. It is removed most easily when it is in large
bubbles, but the action of the pump is to chop it up so
that it becomes a foam, which is extremely difficult to
remove.
Two or three second bursts on the pump at the initial
stage will reduce the risk of foam formation.
Sloping the pipe runs towards the vent points will
greatly aid air removal. Sloping pipes are not just a
feature of gravity systems but can greatly aid the
pumped system because air can move towards a
vent when the pump stops.
Air is dissolved in water but is released when heated.
Always run a system at maximum temperature for at
least 15 minutes to enable this potential problem to be
removed during commissioning.
Commissioning Procedure
The boiler is fitted with automatic ignition and will start
when the gas cock is open, mains is connected to the
boiler and the controls calling for heat.
NOTE:
If the boiler has just been filled with very cold
water, the built in Frost Thermostat will attempt to fire
it if it has a permanent live and no switched live, this
is completely normal. It is recommended that the gas
cock is turned off during this early stage. Because of
a built in delay, the boiler is always held off for a
minimum of 120 seconds. However, for commission-
ing purposes, switch off using the System Isolating
Switch will avoid the delay.
It is strongly suggested that the following stages of
commissioning are followed, and not an immediate
connection of all services. This procedure prevents
substantial amounts of air being dispersed through
the system as small bubbles.