ADVICE - Ferroli Optima 701 - No DHW or CH ?

[bilabonic]

Hi All

I have no DHW or CH from my Ferroli 701 combi boiler.

The fan is running fine, ihave looked at the led status for faults and it gives nothing.

The CH boiler pressure switch is working fine.

The pilot light ignites fine and stays lit so Thermocouple is ok.

The Overheat thermostst is working.
The DHW flow switch is working (led comes on when i open HW tap)
The CH pump is running.

There is a RED led that comes on after about 3 mins and swiyches a relay(RY4) which states 'fan' on the fault finding manual, is this the CH pump ?? As the fan runs as soon as boiler is turned on.

After the red led goes out and the RY4 relay energises i would expect the boiler to light as all comditions are met ?

Anyone got any ideas ?

Thanks

 

[bilabonic]

The problem is the air pressure switch not getting pressure, if i remove the tube that goes upto the fan and 'blow' slightly/apply air pressure to the switch the boiler lights.

What purpose does this switch serve ?

I have checked the pipes etc for blockages/splits but everthing looks fine ?

Cheers

 

[Agile]

It is a safety device to check that the fan is working.

But you have already opened the combustion chamber which we don't advise for a DIYer.

The best advice is to call a gas reg engineer to check the safety of the boiler and diagnose the fault.

Tony

 

[bilabonic]

I have spoken to my GSE and he stated he does not work/install many Ferroli's.

He is coming out to clean the inside and the 'Venturi' and issue me a Gas Safe Cert.

He did mention the PCB as well but i'm sure that is fine.

Does this sound correct ?

Thanks for reply.

 

[bilabonic]

Had GSE out and he has cleaned Venturi/fan blades etc.

He is still unsure whether the fan speed should increase when you call for HW/CH thus activating the APS ?

Can anyone confirm this and how he can check it ?

Would it alter the voltage going to the fan, how does it adjust the speed or should it even adjust it ?

Also how can he monitor if its trying to adjust the speed since he states it has 240v on it constant ?

Thanks

 

[bilabonic]

GSE has replaced the PCB and when it calls for HW/CH the fan now SPEEDS UP!!!

It was NOT doing this before....

It has 80v at normal speed and 230v when full speed calling for HW/CH.

BUT it is STILL not switching the APS ???

He has cleaned the Venturi/boiler etc, checked seals etc, cleaned fan blades.....

He has also tried 'tweaking' the APS setpoint so it fires the boiler BUT when you disconnect the tube from Venturi the boiler still stay lit

What pressure should you expect at the tube coming from the Venturi ?

He is not sure where to go next !!

 

[ollski]

I always replace those brass venturiis, they can be difficult to clean.

 

[Madrab]

Ermmm, maybe time to look at the pressure switch itself?

 

[bilabonic]

I always replace those brass venturiis, they can be difficult to clean.

He has a wire round wire brush thing and cleaned all the inside of it

 

[bilabonic]

Ermmm, maybe time to look at the pressure switch itself?

That what he said but stated that he has only ever replaced a couple of them in all his years plumbing.

He's staing it's either the fan or the APS and that the new APS or not adjustable ?

It's upto me what he wants to try next

 

[bilabonic]

Ermmm, maybe time to look at the pressure switch itself?

That what he said but stated that he has only ever replaced a couple of them in all his years plumbing.

He's staing it's either the fan or the APS and that the new APS or not adjustable ?

It's upto me what he wants to try next

I did ask what pressure should you expect at the APS but he did not know or have anything to test it........

 

[ollski]

He could have read the aps!, very simple to test an aps with a cheap syringe, 5mm silicon tube, a tee piece and a digital pressure tester.

 

[bilabonic]

He could have read the aps!, very simple to test an aps with a cheap syringe, 5mm silicon tube, a tee piece and a digital pressure tester.

The only pressure tester he had was a big thing fo gas testing pressure drop.

I have told him to go ahead and replace the APS as it is cheaper than replacing the fan......

I hope it works or i may as well get a new boiler fitted !!!

I think i understand what you mean by testing the APS, just 'T' off the input to it and measure with a gauge, but there again what should it need to be in order to operate the APS.

I just has a look on Ebay and there are pics of them them with a triangle and 8 or 12 PA, whhich i presume is Pascals.

 

[ollski]

A digital pressure guage can test what the differential is across the venturii which proves the fan and venturii as ok and the syringe kit proves the air pressure switch by gently introducing air via the syringe until the switch clicks the microswitch, then checking the pressure introduced by checking pressure guage. 1 millibar = 100 pascals.