Commissioning The Appliance - Worcester Highflow 400 RSF Installation And Servicing Instructions

12. Commissioning The Appliance

12.1 The appliance is despatched with the controls set to
provide a maximum output for domestic hot water of 24 kW
(82,000 Btu/h) and satisfy a central heating load of 15 kW
(51,000 Btu/h).
The controls can be reset to increase or decrease the heat load
capability from 8.8 kW (30,000 Btu/h) to 24 kW (82,000 Btu/h).
Refer to Section 12.4 – Appliance Operation (Central Heating
Mode).
HOT WATER SYSTEM
Check that the mains water supply has been fully flushed out at
installation.
CENTRAL HEATING SYSTEM
Check that the central heating system has been fully flushed out
at installation.
GAS SERVICE
The complete system, including the meter, shall be inspected
and tested for soundness and purged as indicated in BS 6891.
12.2 APPLIANCE AND CENTRAL HEATING SYSTEM
PREPARATION.
If the cabinet front panel was replaced on final installation (Refer
to Section 11.8) remove the panel before starting the
commissioning procedure. See Fig. 14.
Check that the gas service and the electrical supply to the
appliance are turned off. See Fig. 3 and 17.
Raise the facia and control box into the Service Position. Refer to
Section 11.3 and Fig. 14.
Lower the expansion vessel into the Service Position and remove
the inner casing front cover. See Fig. 16.
Check that all the water connections throughout the system are tight.
Open the system valves at the appliance. See Figs. 3 and 17.
Open all the radiator valves, fill the system and vent each
radiator in turn.
Vent the heatbank from the manual air vent. See Figs. 16 and 17.
The automatic air vent (fixed to the flow manifold) will vent the
boiler section for sealed systems. Do not replace the inner casing
front cover until instructed in Section 12.4 Appliance Operation.
Check the pressure relief valve operates by turning the knob anti-
clockwise until it releases. Water should be expelled from the
discharge pipe. See Fig.15.
SEALED SYSTEMS ONLY.
SET THE EXPANSION VESSEL PRESSURE
The charge pressure of the expansion vessel (as supplied) is 0.5
bar, which is equivalent to a static head of 5 metres (17 ft). The
charge pressure must not be less than the static head at the
point of connection. See Fig 6. A Schraider type tyre valve is
fitted to the expansion vessel to allow the charge pressure to be
increased if necessary.
SET THE SYSTEM PRESSURE
Fill the system until the pressure gauge shows 2.5 bar (37 lb/in
and check for water soundness. Release water from the system
using the pressure relief valve test knob until the System Design
Pressure is obtained up to a maximum of 1.5 bar.
System Design Pressure in bar = Static Head of the System in
bar + 0.3
Note: 1 bar is equivalent 10.2 metres (33.5 ft) of water
Set the movable pointer on the pressure gauge to coincide with
the indicating pointer,giving a permanent record of the set
system pressure. See Fig. 16.
If the pressure indicated on the pressure gauge is greater than
2.5 bar when operating at the maximum central heating
temperature, an extra expansion vessel must be fitted to the
system as close to the appliance central heating return
connection as possible.
The appliance (as despatched) can accommodate a system
volume of about 104 litres. Refer to BS 7074 Part 1. If the system
volume is in excess of that accommodated by the expansion
vessel fitted to the appliance then an extra vessel must be fitted
as close as possible to the central heating return connection of
the appliance.
Any extra vessel fitted must be pressurised to the same figure as
the integral vessel. If the expansion vessel fails then the specified
replacement must be fitted .
12.3 PROGRAMMER.
Any programmer fitted to the appliance should be set up at this
stage following the instructions sent with the programmer.
12.4 APPLIANCE OPERATION.
Check that the electrical supply to the appliance is off.
Turn the room thermostat (if fitted) to maximum.
Set the Operating Switch (or Programmer) to OFF.
In order to thoroughly vent the appliance and system the
appliance may be operated without gas turned on as follows:
Switch on the electricity supply.
NOTE: Immediately the mains electricity is applied to the
appliance the electronic control board is energised causing the
pump to run for about five minutes. This occurs whether or not
the controls are calling for heat. The pump will subsequently
only run in the course of normal operation of the boiler.
Set the Operating switch (or Programmer) to Heating and Water
and the Hot Water thermostat to maximum. The pump and fan
will run, a continuous spark will occur at the pilot electrode, but
the pilot and main burner will not light.
Primary water will circulate around the appliance.
Allow the appliance to operate in this condition for a few
minutes before setting the Hot Water thermostat to the Off
position.
Set the Heating thermostat to maximum and room thermostat (if
fitted) to maximum. The water diverter will open to central
heating and the appliance will operate as previous. See Fig. 16.
Primary water will now circulate around the central heating
system. Allow the appliance to operate in this condition for a few
minutes. Vent all radiators during this period until air is cleared
from the system.
When the system has been vented sufficiently set the Heating
thermostat to the Off position.
Note: The water diverter valve, in the de-energised condition, is
always open to Hot Water. The controls give priority to reheating
the heatbank following a demand for hot water. If the valve fails
to open when energised to the central heating system, hot water
will still be available.
The valve does not have a manually open position.
Set the Operating Switch (or Programmer) to OFF.
Switch off the electrical supply.
The appliance and central heating system should now be vented.
Continue the appliance operation:
2
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Disconnect the electrical supply plug from the solenoid operator
on the gas valve adjacent to the Modureg actuator by
unscrewing the retaining screw. See Fig. 33.
Turn on the gas supply and reconnect the electricity supply.
Put the Operating Switch (or Programmer) to Heating and Water
and turn the Heating thermostat to Max.
A continuous spark will occur until the pilot is alight and sensed
by the control circuit. The fan and pump will run but the main
burner will not light. Test for gas soundness at the joint between
the pilot pipe and the burner with leak detection fluid. See Fig. 34.
Observe the pilot flame. It should be about 20mm (
envelope the spark electrode tip. See Fig. 34.
Put the Operating Switch (or Programmer) to OFF and disconnect
the electrical supply at the mains.
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3 / in) long and
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