Ferolli optima 701 not firing up

[bes]

Hi,
I,ve got gas combi boiler that is not igniting so no DHW or CH. Power supply is OK, but fan does not start at all. Fan relay RY4 is checked and is OK, also fan is fine on its own - if relay bypassed combi starts OK. Pressure is 2-2.5 bar. Any help please?

 

[Agile]

I would ask which relay you "bypass" ?

At this time, and after some Dumisani, I dont remember if your boiler has a flow switch or not. If it has one, then that is the first thing to check!

There seem to be a disproportionate number of questions posted here about this make of boiler.

Tony

 

[bes]

I bypass fan relay (RY4) and then boiler starts properly but only for as long as relay is out of action. Relay tested and OK even tried new one but still the same. It looks like there is no proper command from PCB to switch the relay on - should fan come on after boiler is switched on or there must be some other conditions fulfilled before the fan starts?

 

[Agile]

Most boilers, but not necessarily yours, require a system water flow switch to be made first and then a NC contact on the APS to be made before the fan is started.

I dont remember your boiler in detail so I cannot say what your model does.

You have to understand that when I repair a boiler, I dont use the instructions, but work out how it operates by an inspection of the components and wiring.

Tony

 

[bes]

Hi

Yes there is DHW flow switch and it is activated (can hear clicking and appropriate LED on PCB lights up) when hot water is demanded. I don't know of any other flow switches.
It looks like a job for a corgi man ?

Many thanks for response

 

[Agile]

I said a "system water flow switch" . Thats not the same as the DHW demand switch!

Tony