Combi boiler no heating or hot water


22 Sep 2004
Reaction score
United Kingdom
I have a Ferroli Optima 901 combi boiler which was working fine giving both hot water and heating. I bled a radiator yesterday and found this morning that I had no hot water or heating. I realised that the pressure had dropped to below the minimum of 1 bar and looked on the forum and found how to increase this. I have now increased the pressure to 1 bar but I still have no hot water or heating. Can anyone help? Thanks.
Sponsored Links
Is the pilot alight ?

if not these boilers have a wierd relight up sequence

check selector is set to continuous heating an hot water.
check the electric is on
check system pressure (1 bar)
(if fitted set room thermostat on high)
set boiler thermostst to its maximum setting. after waiting a max of 3 minutes the fan in boiler will run wait another 20 seconds
press the gas control knob fully (this should operate the electronic ignitor).when the pilot flame is seen keep the control knob pressed for 15 secs approx then release it.
should the pilot fail to light wait 3 mins try again.
Yes the pilot light is lit and the boiler seems to be working fine apart from the fact that there is no hot water or heating.
I have a combi boiler, and was fiddling with a rad the other night. the pressure went just below 1 bar.

How do i get the pressure back?

No hot water and no heating - but boiler works(fires up)

call me on 07840436712 please please help!!!
Sponsored Links
I fixed the problem and the boiler is working fine with hot water & heating. I spoke to a plumber who told me that I needed to reset the boiler, done by switching it off and then back on, relighting the pilot light as mentioned above. This worked!

(Answer on how to increase pressure, I turned a valve located next to the boiler, see elsewhere on forum).

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local