Zanussi ULTRA COMBI 35 Installation And Servicing page 32

27 INTERNAL WIRING
DIAGRAM A
Internal Timer or
Programmable Room Stat
ROOM
STAT/
TIMER
L
N
FROST
STAT
( )
OPTIONAL
28 REPLACING PRE-FITTED MAINS CABLE
If it is necessary to use an alternative mains cable to the one pre-fitted then use the
following guide.
Replacement wiring should comply with notes in Frame 31 and be caried out by a qualified
person to avoid a hazard.
1. Isolate the mains supply to the boiler.
2. Remove the front panel. Refer to Frame 37.
3. Swing the control box down into the service position. Refer to Frame 43.
4. Remove the live, neutral and earth wires from the terminal block.
5. Loosen the cable clamp and withdraw the mains cable.
6. Route replacement cable back through the cable clamp and grommet and re-tighten to
provide cord anchorage.
7. Connect the live, neutral and earth wires to the terminal strip. When making the mains
electrical connections to the boiler it is important that the wires are prepared in such a
way that the earth conductor is longer than the current carrying conductors, such that if
the cord anchorage should slip, the current carrying conductors become taut before the
earthing conductor.
8. Swing the control box back up into the operating position and re-fit the front panel
ensuring a good seal is made.
29 EXTERNAL ELECTRICAL CONTROLS
Wiring External to the Boiler
The fuse rating should be 3A.
Wiring external to the boiler MUST be in accordance with the current
I.E.E. (BS.7671) Wiring Regulations and any local regulations.
Frost Protection
If parts of the pipework run outside the house or if the boiler will be left off
for more than a day or so then a frost thermostat should be wired into the
system.
This is usually done at the programmer, in which case the programmer
selector switches are set to OFF and all the other controls MUST be left in
the running position.
The frost thermostat should be sited in a cold place but where it can
sense heat from the system.
Note. If the boiler is installed in a garage it may be necessary to fit a pipe
thermostat, preferably on the return pipework.
32
INSTALLATION
DIAGRAM B
N
Room External
Stat or
Timer
Prog.
Room
Stat
Optional
Frost Stat
Separate Timer and Room Stat
Programmable Room Stat
Use of General Live for Room Stat
Earths are not shown for clarity but must
never be omitted.
ROOM
STAT/
TIMER
L
N
FROST
STAT
( )
OPTIONAL
Timer Room stat
5
Mains In
L N
Room Stat
Programmable
Room
Stat
Mains In
L N
Room Stat
Room
Stat
Mains In
L N
Room Stat
Installation and Servicing
N
Room
Stat
Optional
Frost Stat
Optional
Frost Stat
4
Frost Stat
Optional
Frost Stat
Frost Stat
Optional
Frost Stat
Frost Stat
3G9503