Help needed - Ferroli falcon II boiler. Pump runs randomly

[zulfib]

The pump comes on randomly in summer.
There is no demand from hot water or central heating.
The CH standy light is off.
Uses a wireless timer which is off.

I thought it was the "microswitch" but don't know if these boilers have them. Certainly nothing in the manufacturers literature I could find about these.

Don't believe it is frost protection in summer as the burners remain off but the pump is on (as in overrun).

(I think the Falcon II is the same as the Modena).

 

[Agile]

It could be anything.

Without careful diagnosis its a waste of time to guess!

The PCBs on the Ferollis have not proved very reliable.

It will need someone experienced at diagnosing faults.

Tony

 

[Slugbabydotcom]

Its a feature of many modern boilers that the pump runs for a short while when not in use to avoid risk of it sticking.
Trawl through your instruction manual if this boiler has that feature. It will be mentioned somewhere.

EDIT
I had a trawl through myself and couldnt find such a feature on this model

Frost Protection
In cold weather the boiler may appear to run when there is no demand for heating (i.e. clocks or room thermostats
turned off). This is due to the central heating sensor going into frost protection mode. Once the boiler has
reached 14°C or more it will close down until either the temperature again falls below 7°C or the clock or
room thermostat is turned on.

A faulty CH sensor might cause the pump to run but as you say the burner doesn't fire then this points towards the pcb.

Knowing ferrolis fairly well I would be inclined to eliminate the CH sensor first.
Resistances can be checked as per the manual or for the price of a new one just change it. They do go wrong fairly often on ferollis.
MF03 pcbs are quite expensive and it might be better to live with it for a while if everything else works until the problem manifests itself into one thats easier to diagnose.

Falcon II manual

 

[zulfib]

Thanks guys for your replies.

As we will be needing the heating on in a few weeks, if not sooner - will not be such an issue, I will leave it and see if it develops, though it has not done ir (or we have not noticed it) since I switched the boiler off and started it again a few times (reset?)