Biasi 24S NO HOT WATER - NOT diverter valve membrane

[honcere]

I have a Biasi24S that is ok for ch but not for dhw.
The story is that I had to turn off the water at the main to carry out some work in the bathroom. That completed I turned the water back on to discover that I could no longer get hot water from a tap and the flow was very slow from that tap as well.
I checked this forum and determined that the diverter valve membrane must have split (co-incidence I thought) so I ordered one and fitted it (not a real problem doing that except I forgot to turn water off and was drowned!) but on completion there has been no change - still no hot water and still very low flow.

The whole lot was working perfectly before I started messing - as I'm constantly being reminded!

HELP !! - It's rotten shaving in cold water (nearly a fortnight now) and my wife isn't very happy either

 

[Agile]

Its difficult to guess what you have done wrong but you dont give the impression that you are a very careful worker on boilers!

Possibly looking from underneath you need to see if the DHW demand microswitch is being operated by the diaphragm.

If not then remove diaphragm unit and push the pin and see if that moves and starts up the boiler.

Sometimes the diverter valve manifold gets seized up. Sometimes the gland on the right at the demand switch seizes but replacement is a registered engineer job as the gas valve needs to be removed.

If so then remove the two thin tubes from diaphragm unit AFTER turning off water into boiler. Then turn water back on for a second and see if water comes out of BOTH tubes!

If not then a tube is blocked OR the filter/restrictor is failed. This is accessed from the right of the gas valve and will need a registered engineer to remove the gas valve to gain access to the filter/restrictor.

Tony

 

[minstercourt]

Exactly same thing happend to me, i have stopped the mains and emptied the tank and changed the bathroom taps, once everything finished only little bit of water coming through the hot water, so i called plumber and charger 50 quid for 2 minutes of putting his hand under the hot water tap tightly and hot water came through quickly removing the airlock. so, you could give a try.

 

[bengasman]

What kind of work did you do that made you turn off the boiler?
Is it pure coincidence the boiler stopped, or could you have done something wrong?

 

[Agile]

Exactly same thing happend to me, i have stopped the mains and emptied the tank and changed the bathroom taps, once everything finished only little bit of water coming through the hot water, so i called plumber and charger 50 quid for 2 minutes of putting his hand under the hot water tap tightly and hot water came through quickly removing the airlock. so, you could give a try.

Your situation is completely different as you have a stored hot water system.

The OP has a combi boiler!

Tony

 

[honcere]

What kind of work did you do that made you turn off the boiler?
Is it pure coincidence the boiler stopped, or could you have done something wrong?

I thought the 'coincidence' thing was unlikely, but there could have been a 'surge of pressure' or something I suppose. The boiler has had no spare parts fitted in 5 years - hasn't gone wrong before - so I thought it was about time anyway.
I turned off the water, not the boiler. A plumber, some years ago when re-fitting the bath (had it turned) managed to pipe up the shower with the hot supply where the cold should be and vice-versa. I was re-piping it correctly. It has taken me that long (years) to get round to it because I rarely use the shower at home (NOT mucky! - use one at club)

That shouldn't have beggared it up - should it?

 

[bengasman]

Can you somehow have bridged the hot and cold in such a way that when you open the hot, it actually does not go through the boiler?

 

[honcere]

Turned out that pcb was at fault - new Biasi condensing combo is less than £500, so have decided to cut losses.
Thanks to everyone for responses

David

 

[Agile]

I would say that its MOST unlikely to be the PCB !

Who has diagnosed that and how did they do that? A plumber who looks at it and sucks throung his teeth?

A new PCB would be about £100 but as I said MOST unlikely.

A boiler might cot £500 but who is goiung to fit it?

Tony