Worcester 350 Combi User Manual

1 0.5. FINAL INSTALLATION
Remove the automatic air vent cap. See Fig. 1 9. Replace the inner
casing
coVEr. See Fig. 22.
Check that all the gas and water connections on the manifold have
been
ti ghtened.
Remove the fa cia panel as described in Section 14.2 (a).
Facia Mounted Programmer
Unplug the Operating Switch connection at the control board.
Unscrew and retain the four nuts and washers securing the switch
mounting plate to the
facia . See Fig. 40 . Remove the plate. Fit the
programmer to the
facia and fix using the four nuts and washers.
Plug the lead into the connection X14 on the main driver board.
See Fig. 9b . The programmer can be set when the electricity sup·
ply has been turned on at the commissioning stage.
Connect the mains electricity supply to the appliance and connect
any room and/ or
frost thermostats. Refer to Section 9, Figs. 7 and
8.
The leads from the thermostats must pass through the holes
provided
in the control box at the right hand side and be clamped
using the strain
relief bushes provided in the pack. Check that the
control box can be withdrawn and
lowered before fixing any leads
outs
ide the appliance. To remove t he control box refer to Section
14.2 (b).
Refit the control box and facia.
Test the gas supply for soundness as indicated in BS 6891 .
If the appliance is not to be commissioned immediately, replace
the inner cover panel and the cabinet front pan
el. See Fig . 22 .
Check that the gas supply, the electrical supply and the water con -
nections are a ll turned off .
11 . Commissioning
11 . 1 The appliance is despatched with the controls set to provide
a maximum output for domestic hot water of 35. 2kW (120,000
Btu / h) and satisfy a central heating load up to 15kW (51 ,200
Btu / h) . The controls can be reset to increase the central heating
load capability up
to 25kW (85 ,300 Btu / h) . It is no t necessary to
set an output betw
ee n these figures.
Domestic Hot Water System
Confirm that the mains water supply has been fully flushed out at
installation.
If not, it will be necessary to disconnect the cold water
inlet
pipe from the appliance and thoroughly flush .
Central Heating System
Confirm that t he central he ating system has been fully flushed out
at
in stallation usin g a flushing agent. If not, after the addition of a
su it able flushing agent, drain whilst hot and immediately refill and
re-pressurise. A suitable proprietary inhibitor should be added
when
refilling.
Further information can be obtained from Worcester Heat Systems.
11.2 APPLIANCE AND SYSTEM PREPARATION.
Check that the gas service and the electrical supply to the appli-
ance are o ff .
Check that the Operating Sw itch (or progr ammer) is set to OFF . Se e
Fig . 20.
Check that all the water connections throughout the system are
tight.
Remove the cabinet fr ont panel by pu;lling forward at the
bottom and
lifting it off the top supports.
Remove the inner cover panel by uns crewin g the four screws. See
Fig. 22.
Unscrew the two screws at each en d of the control box. Pu ll for -
ward and low er the control box assemb ly . S ee Fig. 22.
Open the central heating system valves on the manifold. See Fig .
21. Open all the radiator valves and fill the system. The automatic
air vent
(fixed to the flow manifold) will vent the appliance. See Fig.
1 9. Remove the boiler inner casing co ve r to check that the air vent
16
Fig. 1 9. Automatic air vent.
Flue hood fixing hook
cap has been removed. Replace the cover immediately. See Fig . 22 .
Vent each radiator in tum to remove the air from the system.
Check that the pressure relie f valve operates by turning the knob
anti
-clockwise until it releases. Water should be expelled from the
discharge
pip. See Fig. 28.
Remove the plated cap at the front of each pump. 1\Jrn the ex-
posed shaft about half a tum using a flat bladed screw driver.
Replace the plated caps. See Fig. 25.
Set the System Pressure
Fill the system until the pressure shows 1 .5 bar and check for
water soundness.
Release water from the system (through the pressure relief valve )
until the
Initial System Design Pressure is obtained.
Syst
em Design Pressure in bar = Static Head in bar + 0.3.
Note. 1 bar is equivalent to 10.2 metres (33 .5 ft .) of water.
The minimum system design pressure should be 1 .0 bar.
Set the movable pointer on the pressure gauge to coincide with
the indicating pointer
giving a permanent record of the set system
pressure.
Set the Expansion Vessel Pressure
The charge pressure of the expansion vesse l, as supplied, is 0.5
bar wh ich is equivalent to a static head of 5 metres (17 feet) . The
charge pressure must not be less than the static head at the point
of connection
i.e. the height of the top point of the system above
the expansion vessel.
See Fig . 5. A Schraider type tyre valve is fit-
ted to the expansion vessel to allow the charge pressure to be
increased if necessary.
If the system volume is in excess of that accommodated by the
expansion vessel fitted to the appliance, then
an ex tra vessel must
be fitted as close as possible
to the central heating return connec-
tion of the appliance.
The appliance, as despatched, can accommodate a system val·
ume of about 72 litres. Refer to BS 707 4 Part 1, BS 5449 and Table
8. This volume must not be exceeded.
If the expansion vessel fails it must be replaced with the designa t-
ed spare part. See Section 14.4 and Section 15.
11.3 PROGRAMMER.
Any programmer fitted to the appliance should be set up at this
stage.
Detailed instructions are sent with the programmer.
11 .4 APPLIANCE START·UP.
Set the room thermostat (if fitted) to maximum. Set the Central
Heating Temp erature Control Knob on the facia to maximum. See
Fig . 20.
Loosen the screw and connect a pressure gauge to the burner
pressure test point on the gas
valve . See Fig . 26 .
1\Jm the gas on at the service cock. Access is from beneath the
appliance.
See Fig. 28.

Worcester 350 Combi Specifications

General

Brand	Worcester
Model	350 Combi
Category	Boiler
Language	English