The Hot water comes out hot then suddenly turns cold and then very hot burning hot. Could someone give me an idea of what it could be . Thank you

master, January 2010

My boiler switches on for 10 seconds then off, hot wate takes ages and when it does come through it goes cold after about 5 litres worth and then warm again. I have had all the sensors replaced. The gasman thought it might be the PCB but dont want to waste £200 if its something else.
Any ideas?
Thought it might be the gas flow into the house as my cooker has no different between full gas and half, only a difference if you turn down to low.
If anyone who a goo dgasman than can sort this in the Lichfield, Staffs area would be helpful

jer, October 2014

hot water only runs warm unless heatings on can,t get more than 6mb gas at test point but have 20mb inlet pressure. any ideas

dixie, March 2013

People, DONT try to fix your own boiler!! Why put your life at risk, gas boilers can be dangerous in the hands of unskilled people. Do the right thing and call in a boiler engineer who will have better experience of these problems.

combicare, October 2011

trying to run shower and bath off ferroli modena 102 keeps going luke warm/cold then hot again?? is it dhw sensor??i had problem few years ago and i cleaned spade connector for earth wire going to fan as this was all scummed up and hot water ran okay but problem back now??

Steve Collins, October 2011

I had the same problem with my boiler, the hot water would run fine and after running for sometime would cut off. The problem was solved by changing a small part called the ventura. This is found near the fan.

Billy, June 2011

An add on to Nicks answer about taking off the internal cover. I just tried this and didnt need to take off the cover just took out the2 bottom screws and my problem which is as old as the boiler has gone!!
Ferolli help line did not have a clue

Andyb, January 2011

24 v ferroli boiler sf and L2 230v external pump cause pump needs to come on when boiler comes on so do i connect it ? please help

Nick, July 2010

i was told it is the fan
cheap fix on top of the boiler are 2 round holes that have caps on them remove one to the side and the fan will work easier, other wise a new fan is around 200 quid

jayne mason, April 2010

I have changed the hot water temp sensor and the venturi but the problem is still the same, ferroli not very helpful with this one i am afraid, they just go through the parts that it could possibly be.

Nick, April 2010

dont be fooled into thinking the problem is only the dhw or ch thermosts or the water flow meter, it could be something to do with air flow and all, which could be unessacay expensive repairs, i have problems with bath going cold after 15 secs and inconsistent heating.I take the sealed casing off wich cotains fan,etc which strangely relieves the air flow,thus allowing me to have a warm bath and work normal.(BUT I DONT RECCOMEND THIS, AS IT IS DANGEROUS,BUT I DO IT THROUGH DESPERATION,AND GO,S AGAINST ALL HEALTH AND SAFETY).

DAZ, February 2010

as youve had your ch on at over 65 degrees the hw gets to that temp too because of the design of heat exchanger .the water which is boiling hot was stored in boiler and the cold is the mains cold water not heated up yet .the is normal if burners stay on a fault if they go off .advise dont wash or shave in water off combi boilers while taps running ,fill abowl and add cold water to suit

engineer at ferroli, January 2010

hot water thermister sounds like the most possible fault had this problem with ferroli falcon if its the same setup if the modena has a plate heat exchanger this might be the problem

burns heating, January 2010