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4
Boiler installation sequence
4.15.3 Connection details for external time switches
and boiler terminal strip
20 VDC
7
8
9
N
L
3 A FUSE
MAINS
SUPPLY
230 V
50 Hz
Fig. 4.18 Connection details for time switches
If a room thermostat is to be connected in addition to a
time switch the wire between the time switch "ON"
terminal and boiler terminal 4 should be broken by the
contacts of the room thermostat (see schematic layout,
Fig. 4.18).
4.15.4 Vaillant optional plug in timer accessories
Refer to the instructions supplied with the optional
accessories for connection details. Upon completion of
all electrical connections refit the terminal box cover by
pushing into place. The cover is secured by two locking
clips.
4.15.5 Connection details using the VR 65 Control
Center
The VR 65 Control Center is an eBUS system component.
In a storage unit installation, it is responsible for the
communication between the storage unit, the
ecoTEC plus system boilers and external 2- or 3-way-
valves. Connect the VR 65 Controll Center as described
in the enclosed manual.
4.16
Thermostatic radiator valves
The boiler has a built in automatic by-pass valve making
it ideal for use in systems with thermostatic radiator
valves (no separate system by-pass is required). For opti-
mum fuel economy where TRV's are used they must be
used in conjunction with a boiler control interlock. A pro-
grammable room thermostat or separate timer and
room thermostat will ensure complete boiler shut down
when the heating demand is satisfied. (The radiator in
38
(DO NOT USE 7 , 8, 9 IN UK!)
L N
5
3
4
ROOM
SWITCH
THERMOSTAT
CONTACTS
L
CLOCK
N
N
the room containing the room thermostat should not be
fitted with a TRV).
4.17
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 addi-
tional 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.
i
External frost protection cannot be used
when plug in timers are utilised.
4.18
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.
4.19
Anticycling 'economiser' control
The boiler incorporates a built in anticycling control to
ensure that energy wasteful short cycling of the boiler
cannot occur. This control prevents the boiler from
reigniting for a preset period after central heating
operation (the hot water operation is unaffected by this
control and hot water can be drawn at any time).
i
To temporarily override the anticycling con-
trol turn the main boiler on/off switch to the
off position "0" and then back to the on posi-
tion "I" after a few seconds.
4.20
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 (ecoTEC combination boilers only) once in a
23 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.
Instructions for installation and servicing ecoTEC 839592_13
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