Dodgy Ferroli Modena 102

[pootas]

Hi,

Before I even start explaining the problem can I just say I've no idea about any "technical terms" regarding boilers so you will have to make any replies "Idiot Proof".

Basically I've got a Ferroli Modena 102 that won't fire up properly. If I use the reset switch the boiler will fire up for about 5 seconds and then cut out however the boiler shutdown light DOES NOT come on. Throughout the day the boiler may then keep firing up and then down but sometimes it stays on all day.

The main pain is the DHW. If the boiler is on the central heating is fine however as soon as I turn a hot water tap on the boiler will turn off and not fire up again.

The weird thing is that intermittently the boiler works perfectly. Last week both CH and DHW worked fine yet I haven't changed anything and now it is not working again...

Any ideas before I call out a engineer??

Thanks in advance...

 

[HarrogateGas]

A change of both thermistors only about £15 a pair sorts most strange and intermittant faults on these boilers.

 

[chrishutt]

Check that the diaphragm is operating and pushing the lever arm enough to operate the electrical switch.

 

[HarrogateGas]

Check that the diaphragm is operating and pushing the lever arm enough to operate the electrical switch.

diaphragm on a modena???? it has none!

 

[chrishutt]

You're right . I was working on two boilers on Friday, the Modena and a Vokera - got them mixed up!

 

[Agile]

Its usually Chris who has to tell me that!

Can also be problem with the fan/aps.

Tony

 

[pootas]

A change of both thermistors only about £15 a pair sorts most strange and intermittant faults on these boilers.

Thanks for your replies...Like I say I'm not very experienced with working on boilers at all. When you say thermistors do you mean these:

http://cgi.ebay.co.uk/Ferroli-80032...oryZ3191QQssPageNameZWD1VQQrdZ1QQcmdZViewItem

Are these easy to replace? Any chance of a quick guide on how to replace them or shall I just call an engineer out and if I did any idea on how much I should be looking at for the job?

Thanks...

 

[croydoncorgi]

They look like the ones:you need to replace both to avoid messing about! Ferroli sell them in pairs anyway.

They're 'wet' sensors: you need to turn off the electricity supply and the cold water supply to the boiler and isolate it from the rest of the CH (valves underneath), then drain it before unscrewing the sensors. Also, because of the position of the CH sensor, any water left in the boiler will run all over the electronics if you're not careful!