Ferroli Combi

[nabby68]

Hi Guys i have a ferroli domina 80e combi boiler, the problem is that the burners wont ignite. my question is, is there a sequence that all combi's follow in order to ignite, such as fan ,pressure switch, gas valve etc? because the fan is not working and i have tested the voltage to it and it measures 160v, is this correct, should it be gettin 240v?
please help, many thanks.

 

[geoff@cetltd]

If the fan's not running, then nothing much is going to happen

You need to look for things like low system pressure,
overheat stat open circuit
temperature sensor drifted off
it should be XXkohms where you will have to measure it and report back (I had my knuckles rapped for posting the resistance today)
Are you sure thee's a demand for heat?

 

[nabby68]

thanks for reply, there is demand for heat because there is no room stats and so if the fan is not working, will nothing else work?

 

[geoff@cetltd]

If the fan is not working, it won't operate the air pressure switch which is there s[ecifically to prevent the boiler going any further through it's sequence unless the fan isn't working properly

I think the pcb is an MF03 - look in your manual and find out what will prevent it from starting the fan - such as what I posted above

 

[nabby68]

hi raden, looked in manual, but not much information about what starts the fan, just a bit puzzled why the voltage is only 160v at the fan?

 

[geoff@cetltd]

the fan runs on 240 volts

Are you sure you're measuring it correctly?
across the fan terminals - not with reference to earth or something

The fan is driven by a relay on the pcb and so shouldn't be able to be at other than 230v or 0v (I don't think there is a slow fan speed to vent the chamber)

Does the fan actually run ? I would have thought that it should still run slowly at 160 volts

 

[nabby68]

i am measuring across live and neutral and the fan does not run at all. could it be a defective fan?

 

[geoff@cetltd]

I would say so

there's a cooling fan underneath the motor which you can spin to get some idea how freely the fan rotates

have a fondle and see how easily it turns

 

[nabby68]

have done that and it turns very freely, so not sticking at all. still puzzled by the 160v at the fan though. will call ferroli tomorrow and find out if it should recieve more voltage. dont want to pay £100 plus for a fan and find out it still wont work!
what do you think?

 

[Agile]

Better still, disconnect one lead and measure the fan coil resistance and report the result back to us.

You do the measurements and we will reach the conclusions!

Some one elsewhere here today was convinced a switch was "fine" in spite of my strong advice that the symptoms indicated that the switch was faulty. That cost him £85 to have an engineer tell him it was the switch!

Client who I visited today has just been given an OBE, congratulations! Not only did I correctly diagnose her boiler faults but also that she was a Libran too! Not that being a Libran is a fault ! We are all very nice well balanced people!

Tony

 

[geoff@cetltd]

have done that and it turns very freely, so not sticking at all. still puzzled by the 160v at the fan though. will call ferroli tomorrow and find out if it should recieve more voltage. dont want to pay £100 plus for a fan and find out it still wont work!
what do you think?

Well ...

I can't see a reason for the fan voltage being 160 volts. The mains trassformer is on the pcb and has no intermediate tap for a low fan speed not IIRC is there a dropper resistor on the pcb (unfortunately I don't have one to hand)

What is the resistance of the fan coil?

 

[ChrisR]

Check the fan for continuity with it disconnected and power off. No idea about that one in particular but fans usually measure 50 Ohms or so. If you got jiggy with a mains lead and some caution, you could apply mains to it separately.

 

[nabby68]

to measure the fan coil resistance then i measure across live and neutral with my ohmeter?

 

[geoff@cetltd]

Yes,

disconnect it first

Where have all the CORGIs gone ?

be quick - they might not notice

 

[nabby68]

chris r, i do have a megger that will do continuity test but what will this show if measured across the fan terminals?