boiler doesnt heat water for very long

[notaplumber96]

I'm new to this sort of thing so if anyone has an answer can you please write it so its easy for me to understand, I'm definitely not a plumber!

I recently bled the radiators in my house, one of them was completely full of air so I bled it completely, this dropped the pressure in the system. I only bled small amounts at a time and then re pressurised before bleeding again all in the same afternoon.

Since then the boiler has not been heating water well at all. The flame comes on but goes off again quickly and doesnt heat the water. The only way so far I have found to get hot water from the taps is to run them very slowly.

the boiler is a gas combi boiler with no emursion or tank.

Sorry for my spelling and thanks for any help.

 

[Dan Robinson]

Crystal ball time agin

 

[45yearsagasman]

Let me guess, it has a white case.

 

[JohnD]

I reckon its a Fulvio Lanchetta 150G, installed in 1994 and not serviced for 6 years, and the radiators are also cold. The pressure was at 1.5 bar but has slowly dropped to 0.5bar over the last two days. There is a wet patch on the outside wall.

Am I right?

 

[notaplumber96]

Sorry for not putting in the model, should have seen that coming.

The boiler is an Alpha 280e.

 

[Dan Robinson]

Is the pin on the dhw flow valve staying out when the tap is running?

If it is then you could have a clogged HEX or faulty thermisters.

 

[Simon35]

Had same problem on my Worcester combi just last week, OK at low flow, but when I ran the bath tap the temperature indicated on the boiler went up and up, and then burner cut off as did the hot water.

Turned out that the heat exchanger in the boiler was blocked as was a load of other bits of pipe etc.

£400 quid later all is cleaned, new HEX and working as new.

 

[notaplumber96]

Thanks for the advise. I'm not so fond of the £400 later part though! Is this something I would need a plumber for or is there a way to do it myself?

 

[Simon35]

Thanks for the advise. I'm not so fond of the £400 later part though! Is this something I would need a plumber for or is there a way to do it myself?

Dunno, I got British Gas out to do mine, probably not the cheapest option, cheaper than Worcester though. I wasn't too keen on the £400 myself , but one of those things that needed fixing ASAP unfortunately.