3
excel HE -
User’s
Legend
A.
Boiler ON/OFF switch
B.
Main switch & CH thermostat knob
C.
DHW thermostat knob
D.
Pressure gauge
E.
Operational lights (1 & 3) / Fault indication light (2)
F.
Optional programmer
G.
Condensate drain
1
BOILER CONTROLS
Adjustment of the DHW temperature is completely separate
from that of the CH circuit.
The adjustment system integrated within the boiler
automatically controls the flow of gas to the burner in order to
keep the temperature of DHW delivered constant, between the
limits of maximum and minimum output.
Where the demand is at a low level or with the temperature set
to the minimum, it is normal to see a cycle of lighting and
extinguishing of the burner when running.
Adjustment
It is advisable to adjust the DHW temperature to a level suitable
for the demand, minimising the need to mix with cold water. In
this way, the automatic control facilities will be fully exploited.
Moreover, where the amount of limescale present in the water
may be particularly great, not exceeding the position as shown
in the following illustration (about 50
o
C) minimises annoying
incidence of scale deposits and clogging.
In these cases, however, it is advisable to install a small water
treatment device or softener. With such a device you should
avoid periodic descaling.
Consequently, the DHW heat exchanger will keep its
performance consistent for a longer period of time with
resulting gas savings.
To Shut Down the Boiler
For Short Periods
To turn the boiler off set the main switch (B) to the '0' position.
For long periods
When you do not expect to use the boiler for a long period:
1.
Set the boiler 'ON/OFF' switch (A) to 'OFF' and switch the
electricity supply off.
2.
For longer periods the entire system should be drained.
To Relight the Boiler
Repeat the procedure detailed in 'To Light The Boiler'.
Frost protection
excel HE
appliances are provided with a built in anti-freeze
system that operates the boiler when the temperature is below
5
o
C. Internal frost protection operates regardless of the position
of the main switch and CH heating thermostat knob (B).
Therefore, when the boiler is not lit and used in cold weather,
with consequent risk of freezing, the supply to the boiler should
be left switched on.
If the system includes a frost thermostat then, during cold
weather, the boiler should ONLY be turned OFF at the time
switch (if fitted). The mains supply should be left switched ON,
with the boiler thermostat left in the normal running position.
Loss of system water pressure
The gauge (D) indicates the central heating system pressure. If
the pressure is seen to fall below the original installation
pressure of 1-2 bar over a period of time then a water leak is
indicated. In this event a CORGI registered installer or in Ireland
a competent person should be consulted.
Note.
THE BOILER WILL NOT FIRE IF THE PRESSURE HAS
REDUCED TO ZERO FROM THE ORIGINAL SETTING.
Condensate Drain
The condensate drain (G) must not be modified or blocked.
Blockage of the condensate drain, caused by debris or freezing,
can cause automatic shutdown of the boiler.
If freezing is suspected and the pipe run is accessible an
attempt may be made to free the obstruction by pouring hot
water over the exposed pipe and clearing any blockage from the
end of the pipe. If this fails to remedy the problem the
assistance of a CORGI registered installer or in Ireland a
competent person should be sought.
Escape of gas
Should a gas leak or fault be suspected, contact your local gas
supplier without delay.
Do NOT search for gas leaks with a naked flame.
C l e a n i n g
For normal cleaning simply dust with a dry cloth.
To remove stubborn marks and stains, wipe with a damp cloth
and finish off with a dry cloth.
DO NOT use abrasive cleaning materials.
M a i n t e n a n c e
The appliance should be serviced at least once a year by a
CORGI registered installer or in Ireland a competent person.
if7383
3
2
1
C
B
A
F
D
G
E
C
Minimum (40
o
C)
Maximum (65
o
C)
CAUTION. To avoid the possibility of injury during the installation, servicing or cleaning
of this appliance care should be taken when handling edges of sheet steel components
OK
3
2
1
C
201279-6.pmd
02/11/2007, 07:42
63
