Navigation Menu

Ferroli Optimax repairs

Are you experiencing a fault with your Optimax boiler? Book a fixed price boiler repair today by called 0844 272 0941 and we’ll send you a Gas Safe registered engineer to repair it.

Why choose us to repair your boiler?

✔  A fixed price repair
✔  With no call out fee’s
✔  A call out time convenient for you, mornings, afternoons or weekends
✔  12 months guarantee on parts fitted

Call for more information on 0844 272 0941, 

Our lines are open 24 hours a day, 7 days a week.



Below are examples of faults people have experienced with their Ferroli Optimax boiler.


I thought the house was cold this morning when I woke up and it seems my system boiler (Ferroli Optimax HE25S) has a problem. Clearly it wasn’t heating the house, but rather than showing a fault code, the screen was just blank.

I checked the power supply, and also a couple of fuses I found on the main PCB thanks to the wiring diagram in the manual, so nothing obviously wrong in terms of just not having power. Once the cover was off, there was some sign of life – the transformer on the PCB hums (so power there) and there’s a faint hum from something higher up in the boiler, but the main pump isn’t running.

So has anyone else had a similar problem, and is the only solution a replacement PCB? Incidentally, does anyone know the part number for this? There are plenty of online spares places, but I haven’t found a PCB for an Optimax HE25S on their sites.

Many thanks,

Hi. I have a Ferroli Optimax 25c boiler which has been installed about 6 years. I have arrived back from work today and noticed we have no hot water but the rads were warm. I have turned the boiler off, then on after a minute to reset the clock etc. On turning the boiler back on, the following displays were shown, 88 (I presume the LED matrix display test), dp, 26, LU. and then two dashes which means that the boiler is off I think. Since resetting the boiler the rads have now gone cold (or the boiler had just packed up as I returned from work). The fan is on constantly. We have a gas supply, and the hot water seems to flow through the boiler as I can hear it running through the pipes when I turn the taps on. I have now tested the three way valve to the left of the lower components, and have no power at the change over motor(Diverting valve); (Using a voltmeter at the motor terminals). The wires to the motor enters a unit which I think is the CVBC PCB unit situated under what looks like a gas valve assembly, and after taking the cover off, I have noticed a heavy duty resistor burnt out next to a blue capacitor (about 6mm in diameter). This unit looks like it could be a CVBC part DCF02.1 made by Honeywell.

I have since tried to manually operate the change over valve (Diverting valve?) but this has no effect and the boiler won’t light now, and the fan is constantly on. any ideas?