Instructions. V1.01
Page 15
JULY / 2013
Fault
Possible cause
Solution
Over temperature cut-out
operates.
The thermostat has failed.
Reset and if the cut-out oper-
ates again, isolate the unit and
contact the installer.
NB. Isolate the electrical
supply before removing the
cover and ensure that the
cover is correctly replaced and
secured before reconnecting.
The thermostat is set at too
high a temperature.
Regular, intermittent water
discharge from the tundish.
Loss of pressure from the
expansion vessel.
Isolate the heating system and
the mains cold water supply.
Partly drain the unit. Recharge
the expansion vessel to the
specified pressure and re-
commission.
Thermostat failure.
Isolate the heating system and
check the thermal controls
when discharge ceases. Replace
the thermostat if faulty
.
Continuous water discharge
from tundish.
Pressure reducing valve not
operating correctly.
Check with pressure gauge and
replace as necessary.
T&P relief valve not operat-
ing correctly.
Check and replace if faulty.
Expansion relief valve not
operating correctly.
Check and replace if faulty.
No water flow from hot taps.
Cold water mains is isolated.
Check and switch on.
Integral line strainer in
pressure reducing valve is
blocked.
Check and clean as necessary.
Pressure reducing valve is
incorrectly fitted.
Refit correctly with arrows in the
direction of flow.
Water from hot taps is cold.
Power supply not switched
on
Check and switch on.
Over temperature cut-out
has operated.
See fault ‘Over temperature cut-
out operates’ above.
Faulty element.
Check and replace as necessary.
Thermostat failure.
Check and replace as necessary.
Fault Finding