Supplied By www.heating spares.co Tel. 0161 620 6677
28
UNICA BHE
8.1
EXTERNAL WIRING
The appliance comes with a factory fitted (TA)
link to allow basic operation of the boiler via the
mode selector switch. If external controls are to
be added to the system, they must be connected
to the appliance as shown in the following dia-
grams. For advice on controls that are not fea-
tured in this book, please contact Vokera techni-
cal on 0844 391 0999.
8.1.1
EXTERNAL WIRING LIMITATIONS
Any external wiring must remain within the limits
as detailed in the table below:
CONNECTION
MAX. LENGTH
External sensor
30-metres
Room thermostat
30-metres
OT+ connection
30-metres
8.2
TYPICAL CONTROL APPLICATIONS
The appliance can be used with the following con-
trols:
•
single-channel, voltage-free time clocks (fig.
39).
•
programmable room thermostats (fig. 40).
•
OT+ control, please contact Vokera technical
for detailed instruction on specific OT+ controls.
•
vokera external sensor.
8.3
OTHER DEVICES
Contact the controls manufacturer and/or Vokera
technical department should you require more
specific information on the suitability of a particu-
lar control. Further guidance on the recommended
practice for the installation of external controls,
can be found in CHeSS – HC5/HC6
(www.energyefficiency.gov.uk).
SECTION 8
WIRING DIAGRAMS
IMPORTANT
•
The boiler must always be supplied with a per-
manent 230V electrical supply.
•
Always remove the link between TA & TA on the
appliance high-voltage terminal strip whenever
additional controls are connected to the appli-
ance.
•
Do not connect any controls or auxiliary equip-
ment to the low-voltage terminal strip, other than
that approved/supplied by Vokera Ltd.
Fig. 39
Fig. 41
U.H.T.
= underfloor heating thermostat
C.P.A.
= condensate pump alarm
E.S.
=
external sensor
OT+
=
ope connection
OPTIONAL DEVICE (24V) TERMINAL BLOCK
Fig. 40
CH
Time clock
Room
thermostat
F= fuse 3.15AF
CH
Time clock
F= fuse 3.15AF
E.S.
OT+
UHT/CPA