Grant Spira Series - Boiler Overheat Thermostat Faults

85
12.4 Boiler Overheat Thermostat
Primary fault
Secondary follow on checks
BLANK DISPLAY SCREEN
Is the central
heating system
and boiler full of
water and vented of
any air locks?
Yes
No No No No
Is the heating
thermistor correctly
fitted in the pocket
(inside the boiler
control panel)?
Unclip and remove
lead from stat and
check
Is overheat stat
capillary in good
condition and not
damaged, kinked
or broken?
Press reset.
Is there now
continuity between
the overheat stat
terminals?
Is the system
circulating pump
operational?
Is there any
restriction to
water flow from
the boiler?
Remove any
restriction e.g.
open any valves,
or remove
blockage
preventing flow
Correctly fit
heating thermistor
in pocket and
reset overheat
stat
Replace faulty
overheat stat
Replace faulty
circulating pump
BOILER OVERHEAT STAT TRIPPED
Yes Yes
No
Note 1 Note 2 Note 3 Note 4 Note 5
Yes
Yes
Yes
Fill and vent
system