Mamiya C28 Boiler User Manual


 
INSTALLATION
mini HE --- Installation & Servicing
28
33 EXTERNAL ELECTRICAL CONTROLS
Wiring external to the boiler MUST be in accordance with the
current I.E.E. (BS.7671) Wiring Regulations.
For Ireland reference should be made to the current ETCI
rules for electrical installations.
The external fuse rating should be 3A.
Route the electrical supply flexible cord and the external
control flexible cord as illustrated.
Lock the flexible cords in place with the clamps provided.
230V supply
ELECTRICAL CONNECTIONS FOR A
COMBI BOILER
Optional Programmer Kits
Optional digital programmer kits are available with their
relevant instructions.
Bot h 2 4hr and 7day kits are available.
Note: the switch contacts of any external programmer,
room or frost thermostat must be volt free.
Connecting a switched live feed to external controls
terminal block may be dangerous and will result in
serious damage to the boiler.
Room Thermostat
This should be wired as shown in diagrams A.
Frost protection
Central heating systems fitted wholly inside the house do not
normally require frost protect ion as the house acts as a
‘storage heater’ and can normally be left at least 24 hours
without frost damage.
This appliance is provided with a built in anti---freeze system
that operates the boiler when the temperature is bel ow 5 ûC.
Therefore, when the boiler is not lit and used in cold weather,
with cons equent risk of freezing do not isolate the boiler
from the electricity supply or close the gas inlet cock.
However, if parts of the pipework run outside the house or if
theboilerwillbeleftoffformorethanadayorsothenafrost
thermostat should be wired into the system.
To maintain frost protection with the programmer selector
switches set to OFF, all the 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.
Wiring should be as shown, with minimal disturbance to other
wiring.
External Programmers
On the combi boilers, this should be of the single channel
type (as this boiler does not incorporate a pre---heat facility for
the instant aneous hot water service).
Programmers with room thermostat --- see diagram B.
Note. lf the boiler is installed in a garage it may be necessary
to fit a pipe thermostat, prefera bl y on the return pipework.
Earths are not shown for clarity but must never be omitted.
A
Power supply
terminal block
External c ontrols
terminal block
T
Room thermostat
T
Optional frost’stat
12
LN
3
B
Power supply
terminal block
External c ontrols
terminal block
T
Room thermostat
T
Optional frost’stat
12
LN
3
External programmer
N.B. These diagrams are schematic only and do not show
external terminal strips etc.
INSTALLATION