Ariston Microgenus Help Needed

I have a customer whom I installed an Ariston microgenus 31MFFI for a few years ago as part of a new system which has now developed a problem. The symptoms are tepid DHW and he had an RGI out who diagnosed a faulty diaphragm but now refuses (for some reason) to return to fit it. I have no idea why, there's nothing wrong with the customer.

Anyway, would I be right in thinking that there is no diaphragm on this boiler? From looking at the MI’s it would seem that there is a flow switch, an actuator and a three-way valve. So, without looking at the system (it’s a fair trip away) it appears that the flow switch is working so I would suspect the actuator or the valve itself.

Anyone got experience of repairing these boilers who could offer me some advice? Particularly in the area of checking the free movement of the valve or travel of the actuator.

Thanks

Never seen a 31 mffi so im assuming its the same as the others

If your losing power to the rads then id suspect the seals gone in the diverter rather than an actuator fault. However if you remove the the actuator you should be able to see if the pin is travelling as it should.

Dont these use a reed switch for HW? Either way it responds to demand every time then its ok ive never seen a faulty one either.

Pretty basic boiler though. So just the usual checks.

The plate HE on the smaller models are pretty cheap if you have any concerns there.

Just to add ive been to 3 jobs over the past weeks or so with poor HW all have been down to the reduced temp of the incoming mains!

It uses a standard Fugas manifold with the hall effect sensor.



I disconnected this one a couple of weeks ago - the fan had cooked and the flue wasn't fully connected (plus a host of other faults) - cowboy builders gone abroad.