5.18 Anti-cycling ‘economiser’ control
The boiler incorporates a built in anti-cycling control to
ensure that energy wasteful short cycling of the boiler
cannot occur. This control prevents the boiler from re-
igniting for a preset period of 5 minutes after central
heating operation (the hot water operation is unaffected
by this control and hot water can be drawn at any time).
5.19 Automatic pump spin control (APS)
The boiler incorporates a built in control which will spin
the built in circulating pump and operate the diverter
valve once in a 24 hour period. This control helps to
prevent seizure when the boiler is not operated for a
period of time. This control is not active when the power
supply to the appliance is turned off.
5.20 Anti legionella protection
If the temperature in the
power store
does not rise
above a certain limit in a set time period, the boiler will
operate and charge the store to protect against
legionella.
5 Boiler Installation Sequence 5
Fig. 5.14
5.15 Thermostatic radiator valves
The boiler has a built-in automatic bypass valve making
it ideal for use in systems with thermostatic radiator
valves (no separate system bypass is required).
For optimum fuel economy it is recommended that
where TRV’s are used they are used in conjunction with
a programmable room thermostat or separate timer and
room thermostat to ensure complete boiler shut down
when the heating demand is satisfied. (The radiator in
the room containing the room thermostat should not be
fitted with a TRV).
5.16 Frost protection
The boiler has an integral frost thermostat which is
designed for protection of the boiler.
To protect remote or exposed parts of the heating
system or property additional frost protection measures
must be taken such as the installation of an external
frost thermostat. This frost thermostat should be
connected across the boiler terminals 3 and 4, in parallel
with any external heating controls.
Note: External frost protection cannot be used when
plug in timers have been fitted.
5.17 Circulating pump
The boiler incorporates a built in circulating pump that
is fully prewired (no additional wiring is necessary). The
pump incorporates an automatic overrun period after
the boiler switches off.
3
9
8
7
MAINS
SUPPLY
230 V
50 Hz
L
L
L N
N
N
N
20 VDC
DO NOT USE IN UK!
3 A FUSE
SWITCH
CONTACTS
ROOM
THERMOSTAT
CLOCK
4 5
Instructions for installation and servicing aquaPLUS VUI 362-7
22
Note:
To temporarily override the anti-cycling control
turn the main boiler on/off switch to the off position "0"
and then back to the on position "I" after a few seconds.
Note:
Very hot water will be discharged during tapping
after this operation.
834702_33GB_012005.qxd 09.03.2005 16:26 Uhr Seite 22
