Ariston genus combi running continually

[BillHook]

My Ariston Genus combi is continually heating the rads, and reading a water temperature of 70, when it normally only goes up to 40. Hot water is still heating normally, and to the normal heat. The bar pressure is within the recommended range. The boiler is set to 'summer', ie there should be no ch operating. The only way I can stop this happening is to turn the boiler off with the mains switch. I have done this to reset and turned it back on again, but the same thing happened.

Any ideas, anyone

 

[bengasman]

duff diverter

 

[BillHook]

Cheers Ben, it looks like they cost about £75, any idea how long the job takes and rough cost?

 

[Wirral_guy]

BillHook

A long shot admittedly but this caught out the engineer on my boiler (worcester 24CDi) a couple of years ago:

He was trying to locate a fault and switched the gas valve mode switch to max (which makes it run continuously) to run tests. After doing the repair and re-commissioning the system he couldn't work out why the boiler wouldn't cycle and it took him about an hour extra to get to the DOH! moment. Fair play, he didn't charge for it though! (and to all those now laughing - what's the bet that some/most/all of us have done the same kind of thing sometime in their career )

Fairly certain it won't be the case here but has anyone done any servicing just before this happened!

Dave

 

[BillHook]

Thanks for that, unfortunately I don't think it's that simple! I think it's probably the diverter.

Thanks for all your help guys.

 

[bengasman]

Cheers Ben, it looks like they cost about £75, any idea how long the job takes and rough cost?

Hard to say, can be quite a pig to get it out because the connectors can be very stuck in which case you have to take half the machine apart to get enough leverage.

 

[Mark Br]

Do you still get flames at the burner when it is in summer mode and without a call for heat from the hot tap being run?

 

[BillHook]

Yes I do, with no h/w taps open and the heating switched to off, ie 'summer', the burner firesand heats all the time, heating rads

 

[Agile]

Whilst the internals of the diverter valve may be jammed in the DHW position its likely to be much more simple.

Either the DHW demand switch itself is failed closed circuit.

OR

The gland is failed stiff and not allowing the pin to retract and turn off the DHW demand switch.

I dont remember them being that difficult to access although there are a lot of different Ariston models for me to visualise.

Tony

 

[BillHook]

Turned out to be the spring on the switch, new one ordered for Monday!

Thanks a lot for all your help!