Intermittent DHW (Ferroli Modena Boiler)

[cellarboy]

When running the hot tap continuously, the boiler fires up the hot water and runs perfect for about 60 seconds, then the burner shuts off and the DHW light goes out. After about 10 seconds it fires up again and the DHW light comes on. This causes the hot water to fluctuate hot & cold. This all happens while running the tap continuously.

We have just had the heat exchanger and venturi replaced and this is now what's happening.

Any advice welcome & will be passed on to our heating engineer.

 

[twgas]

why were these parts changed?
did you have this problem before the parts were changed?

 

[cellarboy]

why were these parts changed?
did you have this problem before the parts were changed?

Yes, the hot water was not firing at all and hot tap was no more than a trickle before the heat exchanger was replaced. The venturi was broken whilst examining (britle due to age), so was also replaced.

 

[twgas]

what is the HW flow rate?
which model of modena have you got?

 

[cellarboy]

Sorry, I have a correction to make...

The TAP light stays on when the FLAME cuts out (FLAME light goes off).

 

[cellarboy]

what is the HW flow rate?
which model of modena have you got?

Not sure of Flow Rate, but it's a Modena 80E (03)

 

[cellarboy]

Our engineer's just been out and taken a look. He thinks it could be the Test Point, as it's also showing signs of breaking up (britle). For the sake of a couple of quid, we'll see when it's replaced what happens.

 

[Dan Robinson]

Test Point

?????

 

[cellarboy]

Test Point

?????

See here: http://www.akgas.co.uk/Ferroli-Fan/Ferroli-Domina-Modena-Test-Point-39805600.html

 

[Dan Robinson]

Still none the wiser.

How does he think this is affecting your boiler.

 

[sandybeach]

When the flame drops off during hot water demand, get your engineer to remove one of the caps that sits on top of the outer combustion box.

If the boiler fires up after removing the cap then the problem will definitely be with the fan venturi or the test point.

If this is the problem,make sure your engineer gives the fan blades a good clean. I've had a few problems in the past where the new venturi's haven't worked until i'd cleaned the fan and other call outs where i had to replace the fan unit.

 

[paulandfrodo]

I had a ferroli fitted in a refurb 2009. It broke down (DHW) within the warrantee period. It took them 2+ months to fix it, in the end replacing the whole unit. It was the biggest pain in the arse I have ever experienced. 1 service engineer in an area of a million square miles (well, not quite, but you know what I am getting at).

I have never interacted with such an incompetent finger pointing bunch of idiots in my life. I will never skimp on a boiler again.

Yes, as you guess, i was not happy with them.

But, I did persevere and get my boiler fixed. But it was hard. Next time it goes wrong, its going in the bin.