The company reserve the right to alter size, shape and specification without prior notice
TMS-UT-0804-Z01-4
page 20
RCCB switch cannot
be switched ON
Check existance
of resistance
between terminals N,3,5,7
or RCCB switch and PE
Find component which has
contact between earth (PE) and
change it.
YES
Please check the following
before going through Fault
finding chart.
Check the installation is
correct.
All isolating valves are open.
The system is full of water
(pressurised) and purged of
air.
Programmer and controls
outside of boiler are on.
Check the electrical supply is
connected correctly and
present
Check the
status of safety
thermostat, try to
reset it
Switch on RCCB switch
YES
NO
Change the RCCB switch
NO
Boiler ''roars''
while heating
Check the
water pressure
and vent the
central heating
system
Defective immersion heaters
- change the heaters
YES
Please check the following
before going through fault
finding chart:
Check the installation is
correct.
All isolating valves are open.
The system is full of water
(pressurised) and purged of
air.
Programmer and controls
outside of boiler are on.
Check the electrical supply is
connected correctly and
present
Central heating
system was not
vented properly
Lower the speed on
central heating pump
(see guide below)
YES
NO
9. After Sales service information
If after using the fault-finding guide above the problem cannot be rectified by the installation engineer on site, a
qualified Oso Service Engineer is available during normal office hours to attend a breakdown.
A charge will be made if:
There is not a fault with the Termo boiler or the breakdown was caused by incorrect installation of the product that
does not conform to the installation manual.
Components fitted on the system that were not supplied by Oso are preventing the satisfactory operation of the
Termo boiler.
