14
5. MAINTENANCE, SAFETY AND SERVICING
Maintenance must be carried out by a compe-
tent person.
5.1 Draining/flushing
1. Turn off mains supply.
2. Connect hose pipe to drain cock on cold wa-
ter supply pipework. If bottom immersion is
to be replaced then additionally open drain
cock at base of cylinder (21).
3. Open hot tap. Open temperature & pressure
relief valve.
4. Allow vessel to drain. Follow commissioning
instructions (above) to refill.
5.2 Recommissioning
Cold or tepid water discharge from tundish
The tundish should be installed away from electri-
cal devices.
1. Close cold water supply valve
2. Open a hot tap.
3. Repressurize the expansion vessel air charge
to its set level.
4. Close hot tap
5. Open the cold water supply valve
Hot water discharge from tundish: This indicates a
malfunction of a thermal cut-out, operating ther-
mostat or the combined temperature and pressure
relief valve. Turn off the electrical supply to the
immersion heater and also isolate an indirect unit
from the boiler.
Contact the installer or competent engineer.
5.3 Safety and maintenance
Safety cut-out
1. The safety cut-out operates if:
a). Wiring is incorrect.
b). The immersion heater thermostat or
cylinder thermostat fails.
c). Thermostat is set too high.
2. Remember before resetting the safety cut-
out or altering the thermostat setting, isolate
electrical supply to the unit prior to removal
of the electrical box lid.
3. Reduce thermostat setting and press the re-
set button. After adjustments are completed,
ensure the lid to the electrical box is replaced
correctly and the retaining screw is fitted.
4. If still out of operation, contact installer.
Pressure reducing valve
1. Isolate the cold water supply and open a
ground floor cold tap.
21
Reset button
Safety
cut-out
Working
thermostat
Temperature
adjustment
screw
RESET
RE
SET
M2
1
2
3
4
THERM-O-DISC
40°C
70°C
60°C
50°C
1
2
Power
supply
