Protherm 100 User Instructions - page 23
23
FAULT FINDING
Before fault finding, make sure that:
•
All gas cocks are open and there is an inlet gas pressure of 20 mbar.
•
The heating system pressure is at least 1 bar.
•
There is a permanent mains supply to the boiler.
•
The fuse on the PCB is intact.
•
All external controls are correctly wired and calling for heat.
WARNING:
Always isolate the boiler from the electrical supply before carrying out any electrical replacement work.
Always check for gas soundness after any service work.
Digital display shows:
– CHW temperature (no decimal point displayed)
– DHW temperature (decimal point lights)
– diagnostic error messages
As soon as the mains switch is on the display shows for a very short time the version of software used. It has no
importance for boiler operation.
Diagnostic error messages
In the event of a fault, the following diagnostic error messages will be displayed.
Message Fault
Action
Comments
F0
Flow rate sensor failure
Check sensor
Pump runs for one minute
Loss of system water
Refill system-check for leaks
Pump runs for one minute
Air lock in boiler.
Bleed boiler and system
Pump runs for one minute
Pump failure
Check the pump
F1
No flame detected
Check flame sense electrode
Boiler shuts down and
Check ignition electrode
pump runs if there is CH
Check ignition unit on gas valve
or DHW demand
Check fan operation
Overheating
Reset overheat thermostat
F2
Central heating thermistor failure
Check flow thermistor
Boiler shuts down
or
CH water temperature below 3 °C
Check if system is not frozen
F3
Heat exchanger blockage
Check main heat exchanger
Boiler shuts down and
Check domestic heat exchanger
pump runs
F4
Domestic hot water
Check thermistor/leads
Domestic hot water is
thermistor faulty
available but poor
Flashing decimal point when DHW temperature is displayed
This indicates that the domestic heat exchanger may be partially or fully blocked, the pump may be running too
slowly or the central heating flow rate is too low.