Supplied By www.heating spares.co Tel. 0161 620 6677
16
The slow ignition pressure level can be set during the first
10 seconds following burner ignition.
After setting the pressure level upon ignition (STEP)
according to the type of gas, check that the pressure
for heating is still at the value previously set.
4.4
SETTING THE D.H.W. FLOWRATE
A restrictor nut is fitted into the diverting valve to reduce the
D.H.W. flow to that which will give an acceptable D.H.W. tem-
perature. To set the D.H.W. flow, procede as follows:
– select Summer position “
” and turn the D.H.W. thermo-
stat to max.;
– fully open the D.H.W. tap furthest from the boiler;
– check that the boiler is firing at maximum burner pressure;
– adjust the D.H.W. flowrate by turning the restrictor lever
on the divertor valve until a D.H.W. temperature rise of
appr ox 35° C is achieved. This corr esponds t o t he
flowrates shown in
Table 4;
– turn off the tap;
– remove the pressure gauge and refit the sealing screw;
Remember that the flow rates and corresponding temperatures
of use of hot water, given in
Table 4, have been obtained by posi-
tioning the selector of the circulation pump on the maximum value.
Should there be any reduction in the D.H.W. flow rate, the filter
installed on the inlet to the pressure switch valve may need
cleaning. To gain access to the filter, first close the cold water
isolation valve (20, figure 2), drain the D.H.W. circuit via the low-
est tap, make provision to collect a small discharge of water,
then loosen the brass swivel connection to access the filter.
4.5
FINAL CHECKS
– Re-light and test for gas soundness.
– Re-fit the casing front panel and securing brackets.
– Set the C.H. and D.H.W. potentiometers to the required
settings.
– Ensure that the time clock is set at the desired time peri-
ods. Set the room thermostat (if fitted) to the required
setting.
4.6
USER’S INSTRUCTIONS
Upon completion of commissioning and testing the system,
the installer should:
– Give the “Users Instructions” to the householder and
emphasise their responsibilities under the “Gas Safety
(Installation and Use) Regulations 1996 (as amended)”.
– Explain and demonstrate the lighting and shutdown proce-
dures.
– Advise the householder on the efficient use of the system,
including the use and adjustment of all system controls
for both D.H.W. and C.H.
– Advise the user of the precautions necessary to prevent
damage to the system, and to the building, in the event of
the system remaining inoperative during frost conditions.
– Explain the function of the boiler overheat thermostat, and
how to reset it. Emphasise that if cut-out persists, the boil-
er should be turned off and the installer or service engi-
neer consulted.
– Stress the importance of an annual service by a regis-
tered heating engineer.
