Ariston SX20 Eurocombi no running hot water.

[davewizz]

Hi, this is the problem.

Ariston SX20 Eurocombi, c/h working fine but now no running hot water.
Boiler does not change over modes when hot tap is turned on from c/h to providing hot water.

If heating is off and burner unlit, when tap is turned on, burner does not ignite.

BUT works every now and then and when it is working if you turn the tap off it doesn't kick back in. eg works once every ten times.

The water diaphragm was last replaced in 2002 as it was perished.

Not relating to this problem, I have replaced the pump and the main circuit flow switch within the past 6 months on this unit. Flow switch contacts are working.

I'm thinking of first replacing the water divertor diaphragm and giving it a clean up.

Would appreciate any thoughts.

Thanks in advance

dave

 

[Paul Barker]

I've got news for you, a 2002 diaphragm is doing well if it still works. I only yesterday redid one that was done 4 years ago. Took me about 15minutes from entering house to saying goodbye with them having hot water.

 

[davewizz]

Hi thanks for the reply. Yes I think the part has lived a very useful life and now is due for replacing, start of week once I've got some prices.

How similar are the symptoms of your repair compared to my post ?

cheers

dave

 

[ChrisR]

Just look att he pin sticking out of the diverter valve to see if it's probably the diaphragm.

 

[davewizz]

Hi Chris, the pin from the top of the divertor into the block looks ok. Just a small amount of corrosion round the area where the pin comes out of the divertor.

What are you thinking about pin condition ?

I'll check the contacts though on the block above the divertor.

cheers

dave

 

[Agile]

He is thinking that its not moving when you turn on a hot water tap!!!

Tony

 

[davewizz]

Q the Homer Simpson (Peter Glaze) classic D'OH ! From myself.

I've not had a lot of sleep so thats my excuse.

I'll check it out.

dave

 

[davewizz]

Divertor pin moving up when tap turned on and back when turned off.

Diaphragm at fault ?

cheers

dave

 

[ChrisR]

Does it push the microswitch button(s) right in?
shouldn't need more than about 3 l/min at the hot tap.
If so, as ...

when tap is turned on, burner does not ignite.

check the switches.
If not, change the diaphragm.

 

[davewizz]

Thanks for the advice.

It doesn't push all the way into the switch block to activate the change over to ignite the burner for running hot water. Though goes up and down with relevant tap position.

If I manually push the the plastic connector that the pin controls up an extra millimeter or so it all kicks in fine. Try the tap again and it's the same with it not going that extra mill further.

A dodgy worn diaphragm ?

cheers

dave

 

[davewizz]

Worked out a temporary solution to the problem.

If the diaphragm is more than likely on the road out and worn. It's unable to push the pin high enough up to switch over from central heating to running hot water.

I placed a small piece of insulating tape between the pin and the plastic underneath the switch block.

By doing this it seems to have compensated for the wear in the diaphragm and allows the pin to once again switch between c/h and running hot water.

I'm still going to replace the diaphragm but am now curious as to how long this will work as its working fine just now and has been all day.

Cheers

dave

 

[Agile]

I placed a small piece of insulating tape between the pin and the plastic underneath the switch block.

I am sorry but you have done that wrongly too !

You should have glued a 5p coin on the top of the switch pusher!

Tony Glazier