Ferolli Modena 80E - Lukewarm water

[dangermouse]

Looking for any inputs at all. The boiler is approx 7 years old.Has and is pretty much working ok except that regardless of the position of the dial for DHW temp, the water is at best 'lukewarm'. If the hot water tap is turned on slow, the water heats up slightly but then when the flow is increased, this dies off. This is even with the dial at MAX. I appreciate that the outside temp is almost below freezing but it seems pretty poor to me. CH is working fine

 

[REDSAW]

seems like the thermistors /electrodes have gone?

 

[migoplumber]

as above

 

[Puddle]

can go with thermistor
but any problem with electrodes would show up on heating side as well

 

[dangermouse]

I am not saying for 1 minute I have anywhere the same expertise as a Gas Engineer, but I have been an Eletronic Technician for around 17 years. Would I be able to replace these or would it be outwith my capabilities? Is this an expensive part?

 

[moogwai]

does the burner go on and off whilst using the hot water?? I had a problem like this on a ferroli f30 where the hot water would only get luke warm with burner firing for a short time then go out then do it again.
Turns out it was the fan venturi,changed that and problem was solved.

 

[RoryD]

Usually the thermistors, with Ferrolis you should always change both. I always do the basics first i.e. Burner pressures etc.. have had a couple recently with sulphidation. But all the aforementioned are valid points.
May you all have a Safe, Happy.... and of course, a prosperous New Year

 

[dangermouse]

(to earlier post) The burner remains on, just the water doesnt appear to be anywhere near the temp I would expect especially with the dial at 'max'

Thanks for all the advice. I have to be honest.The boiler has been very reliable up to this point and it hasnt been serviced routinely.just one of those things that I havent bothered with

 

[payney1974]

if your burner stays on but your waters not very warm i should get it serviced as gas pressures need to be checked

 

[Blackcatgas]

Looking for any inputs at all. The boiler is approx 7 years old.Has and is pretty much working ok except that regardless of the position of the dial for DHW temp, the water is at best 'lukewarm'. If the hot water tap is turned on slow, the water heats up slightly but then when the flow is increased, this dies off. This is even with the dial at MAX. I appreciate that the outside temp is almost below freezing but it seems pretty poor to me. CH is working fine

Run the hot water, locate the hot water heat exchanger, put your hand on the primary flow pipe (the pipe from the boiler going into the heat exchanger), is it red hot? if it is and the water coming out of the tap is still luke warm then your hw heat exchanger is scaled/sludged up.

 

[payney1974]

Run the hot water, locate the hot water heat exchanger, put your hand on the primary flow pipe (the pipe from the boiler going into the heat exchanger), is it red hot? if it is and the water coming out of the tap is still luke warm then your hw heat exchanger is scaled/sludged up.

Does this model have a seperate h/exchanger for dhw?

 

[Puddle]

Run the hot water, locate the hot water heat exchanger, put your hand on the primary flow pipe (the pipe from the boiler going into the heat exchanger), is it red hot? if it is and the water coming out of the tap is still luke warm then your hw heat exchanger is scaled/sludged up.

The Modena does not have a seperate plate heat exchanger for hot water,heating and domestic hot water both go through and are heated through the main heat exchanger

 

[Blackcatgas]

The Modena does not have a seperate plate heat exchanger for hot water,heating and domestic hot water both go through and are heated through the main heat exchanger

ahhhhh..... Thats told me then, I always try to only post about somthing if Iam sure! lol.
perhaps then with the temp outside being -2 the 7yr old modena 80 is strugling a little.

 

[RoryD]

Run the hot water, locate the hot water heat exchanger, put your hand on the primary flow pipe (the pipe from the boiler going into the heat exchanger), is it red hot? if it is and the water coming out of the tap is still luke warm then your hw heat exchanger is scaled/sludged up.

It'll be the main heat exchanger - no plate to plate on this model. could inject fernox cleaner thru the filling loop, it will definitely help short term