Fault Finding
NB All servicing and repairs must be undertaken by a competent person,
familiar with unvented systems.
Fault
Possible Cause
Solution
Over temperature
The thermostat has failed
Reset. If the cut-out operates
cut-out operates
again isolate the unit and
The thermostat is set at
contact the installer.
too high a temperature
NB Isolate the electrical supply
before removing the electrical
cover panel and ensure that the
panel is correctly replaced and
secured before reconnecting
Regular,
Loss of pressure from
Isolate the heating system and
intermittent water
the expansion vessel
the mains cold water supply.
discharge from
Partly drain the unit. Recharge
tundish
the expansion vessel to the
specified pressure and
re-commission.
Thermostat failure
Isolate the heating system and
check thermal controls when
discharge ceases. Replace
thermostat if faulty.
Continuous water
Pressure reducing valve
Check with pressure gauge and
discharge from
not operating correctly
replace as necessary
the tundish
P&T relief valve not
Check and replace if faulty
operating correctly
Expansion relief valve not
Check and replace if faulty
operating correctly
No water flow
Cold water mains supply
Restore mains supply to the
from hot taps
isolated
heater
Integral line strainer in
Check and clean as necessary
pressure reducing valve
has become blocked
Pressure reducing valve
Refit correctly with arrows in
incorrectly fitted
direction of flow
Water from hot
Power supply not
Check and switch on
taps is cold
switched on
Over temperature
See fault “Over temperature
cut-out has operated
cut-out operates” above
Faulty element
Check and replace as necessary
Thermostat failure
Check and replace as necessary
14
Zip Varipoint III Installation, Maintenance and User Instructions - August 2008
Varipoint qxd:Varipoint qxd 22/8/08 11:09 Page 12
