VOKERA Linea Installation & Servicing Instructions Manual - page 23
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19
Linea Max
6.6.8
Setting the Maximum Rate for Central
Heating
The maximum heat input for the central
heating mode is not adjustable.
6.7
Checking the Flue System
6.7.1
The flue system should be visually checked
for soundness. Check all clamps and fixings
are secure and tight.
6.8
Checking the Heating Thermistor
6.8.1
Allow the system to warm up and manipu-
late the c/h control knob to ensure that the
burner modulates between high and low
and then to off and vice versa (scale range
covers approx. 45° - 85°C).
6.9
Regulating the Central Heating System
6.9.1
Fully open all radiator and circuit valves and
run the appliance in the central heating
mode until heated water is circulating. If
conditions are warm, remove any thermo-
static valve heads.
6.9.2
If the burner will not light, ensure that water
is in fact circulating. See 4.6.3.
6.9.3
Adjust radiator return valves and any branch
circuit return valves until the individual
return temperatures are correct and are
approximately equal.
6.9.4
When all is adjusted, progressively close all
radiator valves to ensure that the appliance
still operates when flow through the system
is limited.
If the burner cuts out prematurely due to
lack of water flow through the appliance, the
system should be regulated to ensure a flow
rate of at least 350 litres/h (78 gals/h). This
may mean the addition of a small manual
by-pass being fitted to the system if a fully
TRV system is used.
6.10
Final Flushing of the Heating System
6.10.1
The system should be flushed in accord-
ance with BS7593:1992. Turn on the boiler
for central heating and allow the boiler and
system to reach temperature. Turn off the
boiler and drain the system whilst hot.
Refill the boiler and heating system as
described in 6.3.3.
Although not necessary for correct operation
of the boiler an inhibitor may be added at
this point. Contact the inhibitor manufacturer
for further information concerning applica-
tion and required dose.
6.10.2
Inspect the system for soundness. Turn the
appliance off at the mode selector switch.
6.11
Filling, Testing and Regulating the
Domestic Hot Water System
6.11.1
Start with the appliance switched on having
completed the procedures described in 6.4
to 6.10.
6.11.2
Open a domestic hot water tap (Preferably
the bath tap).
Ensure cold water inlet stopcock is fully
open (horizontally to the right) and the dhw
control knob is set at maximum.
6.11.3
The flow of water should activate the do-
mestic hot water flow switch (13) and drive
the diverting valve (21) to its hot water
position thus heating the domestic water
flowing through the dhw heat exchanger. At
the same time the pump and fan are acti-
vated lighting the burner on maximum rate.
6.11.4
If the burner does not light, check that the
water flow rate is above the minimum
required to operate the domestic hot water
flow switch (13) 2.0 litres/min (0.45 gals/
min).
6.11.5
The temperature of the water will depend on
the rate at which it flows and the amount of
energy stored in the primary store.
The temperature of water at the tap can be
varied by adjusting the water flow rate at the
tap up to the maximum predetermined
quantity.The hot water temperature control
knob will govern the maximum temperature.
When the appliance is being used in hot
water mode the temperature indicator
indicates the temperature of the hot water
leaving the appliance.
6.11.6
It is best to set for the lowest acceptable
temperature since the user can gain higher
temperatures by restricting flow at the tap.
N.B. If the cold supply is subject to large
fluctuations or is above the permitted maxi-
mum a suitable pressure/flow regulator
should be fitted in the cold water supply to
the appliance.
6.11.7
Turn the appliance mode selector switch to
the position.
Slowly close the tap to reduce the rate of
draw to above the minimum approx. 2.0
litres/min., (0.45 gal/min.) Rotate the dhw
control knob to ensure the appliance modu-
lates at its various setting.
6.11.8
Close the draw-off tap still further. The
burner should stop when the rate falls below
approximately 2.0 litres/min. (0.45 gal/min.),
and the primary store temperature is replen-
ished.
6.11.9
The appliance incorporates a hot water
preheat facility. The appliance will therefore
ignite periodically to maintain heat within the
thermal store of the appliance.
6.12
Final Check for Operations
Turn mode selector switch to the OFF/
RESET position, disconnect pressure
gauge, re-tighten screw. Relight boiler.
6.12.1
Re-check for gas soundness
6.12.2
Re examine heating and hot water systems
and cold water supply for water soundness.
6.12.3
Check the appearance of the gas flame to
assess adequacy of combustion air supply.