Ariston microgenus boiler:

[jimmy1979]

Hi there can someone please advise me on this problem i am having. Last week my partner asked me to have a look at her mums boiler which was installed three years ago. apparently the boiler is working fine on central heating but when you turn the hot tap on to ask for water, the water is coming out cold. The boiler is trying to fire but keeps going off after 3 seconds or so and then trying to fire again after 5 seconds. I have changed the main flow switch but still no joy. Can someone tell me what it could be as my partners mum cannot really afford a new boiler. Many thanks.

MOD 2

please don't hijack threads it causes confusion

your post has been split

 

[ChrisR]

PLease start a new thread. Exactly what boiler is it?

MOD 2

split

 

[jimmy1979]

Hi I have been looking on the internet and it is very similiar to the TX 23 MI model but ours has the temperature lights on it as well. I am looking for the booklet as we speak.

 

[steffan]

secondary heat exchanger blocked?? Try cleaning it.

or, thermosistor faulty, or rubber membrane controlling flow switch worn out

 

[jimmy1979]

hello again, I have found the manual for the boiler and can now tell you that it is the 23/27 mffi model. I have changed the main flow switch and membrane but still only a bit of hot water comes through then it goes cold and back to square one. I think I need to change the D.H.W flow switch now behind the pump but i need advice if this will sort it.

 

[Agile]

Why not read Stephans post about your blocked plate HE ?

Tony

 

[jimmy1979]

Is the secondary heat exchanger easy to clean out>whats the best way to clean it out and what with exactly. i.e plain water or put something in it.

 

[kevplumb]

see this for a few tips

 

[jimmy1979]

Hello again i have cleaned out the secondary heat exchanger and changed the d.h.w flow switch and d.h.w temperature sensor. Unfortunately still no joy. I did ring ariston and they sdaid it could be the air pressure switch but i am a bit unsure as now we are getting hot water when the central heating is on and no hot water when it is off.

 

[booghalamoon]

Jimmy, I think that most probaly your diverter valve is not operating coorectly, hence leading to the overheating of your system and shutting it off. I had the same problem with the same symptoms. The stupid Ariston guy couldn't find out after visiting twice finally I asked him to check that one, and there it was!