Biasi boiler making banging, whistling noises

Hi Guys,

My Biasi Combi boiler is making banging, whistling noises. Central heating works properly, but when it comes to hot water it comes in waves hot/cold, hot/cold. Noise is being observed only when there is a demand for hot water. What is the issue?



Hi Oliver,

I think detail investigation is needed. You should contact GasSafe Registered technician, as it may be a pump, burner/igniter issue or even PCB. GasSafe technicial will be able to tell after 5 min what’s wrong and you end up replacing only this part which is faulty, not all the parts that may be faulty. At the end it is probably cheaper solution

Biasi Combi boiler doesn’t light


I have a Biasi Prisma 24SE combi boiler, and I tried to release the air from the system and then refill with water. Everything went fine- at last I thought so till I tired to light the boiler. It didn’t work for the first time so i restated and then restarted and then…. again. Now boiler doesn’t work. Any idea on what may have gone wrong and how to correct it?
Any help appreciated


Hi Bruce

How many times did you press the reset button? Did you let the boiler to cool down between pressing? Each time boiler tried to light (lighting sequence started) but failed? My guess would be that the air is locked inside of the boiler, replacing air vent should solve the issue.

Biasi s24 red light on


I have just moved to a house. There is Biasi S24 boiler. I tried to switch it on and red light appeared. I restarted- no improvement. Boiler is not working. Can someone help me?


Hi Andrew

If house was not used for a while, first of all I would check the water system pressure. It should be somewhere between 1.5-2 bar. If lower re-pressurize the system, and then restart your boiler again. If you have no idea how to re-pressurize call GasSafe engineer in our area and he will be able to help you


Biasi GARDA HE MK2 no hot water


I have a I have a Biasi GARDA HE Combi boiler model MK2 M96A.28SM/B. It produces hot water for very short time only- not enough time to have a shower. I observed that in those cases boiler flame goes on and off, not staying on for long enough. Central heating works normally. Any idea what happened? Restarting does not solve the issue.


Hi Alan,

I would suggest simple heat exchanger replacement. You will find the description in the “troubleshooting” section of this page, and can buy the part in the shop. Naturally you should be using qualified personnel for this. 

Biasi M90 24S fails to ignite


My Biasi M90 24S permanently fails to ignite. I can hear that the ignition sequence starts  goes for few seconds and then stops just before sparking. What is wrong and can I fix it myself?

Best Regars


Hi Tim

There are many parts that can be responsible for ignition failure like:  burner, temperature sensors, PCB, different electrodes, cables or even an air pressure switch or a pump. I would advice calling GasSafe registered boiler specialist or Biasi customer service and request a visit/repair. You need someone experienced to fix this kind of issue.

Biasi 24s Combi no hot water

Hi Folks,

I have a Biasi Combi boiler model 24s, that I have purchased 7 years ago, and it was doing a very good job so far. I use it for both central heating and hot water. Yesterday hot water finished… I restarted the boiler- no luck. Does anyone know what may be the issue?

Best Regards


Hi Robert

Your issue can be solved by replacing either diaphragm split in the diverter valve (simply exchange the whole diverter valve) or/and DWH temperature sensor . I would probably replace both- just to stay on the safe side. Let us know if it worked

Biasi Riva Compact HE


I own a Biasi Riva Compact HE boiler and sometimes it has an issue with lightening/providing hot water. There is no special error message associated with it. What I do is simple reset the boiler and it goes back to normal operation, just recently is happens every week, so I started to wonder what is causing it. Does anyone have an idea?


Hi Euan,

It is actually quite a common issue with Biasi Riva Compact and as you discovered yourself simple resetting fixes the issue, however if it occurs to often I would recommend replacing PCB. That should permanently fix ignition/no hot water issue.