Saunier Duval Combi - Help!

[Antz]

No local plumbers are interested. They all hate Saunier Duval.

I inherited this thing when I bought my house 3 years ago.

Latest problem.

Pushed the on/off button on front of boiler to turn off. Went to turn on again and blew the 3amp fuse.

No good at this stuff. Local plumber looked. Changed to 5amp fuse and blew that. Called his Electrician mate.

Leccy mate says powers ok to boiler, but something in boiler is kicking back and doing the fuse. 'Don't know anything about boilers mate.'

I'm stuck.

Anyone come across this before by chance?

 

[kevplumb]

View media item 11303

 

[gas_man_gaz]

daft question but it ant been leaking has it? it's what they do best!

 

[Antz]

Leaking is about the only thing it hasn't done yet.

Something to look forward to I suppose.

No signs of leaking. Don't think thats shorting it out.

 

[mickyg]

whats the boiler model??????????????/

 

[Antz]

Isoffast 35e

 

[bengasman]

What is the pressure you normally keep it at, and how often do you need to top it up?

 

[Antz]

1.5 / 1.6 ish.

Hardly ever top up.

 

[bengasman]

In general, I would say the most likely culprits are:
1. pump
2. fan
3. pcb.

 

[Antz]

Thanks for that. I'll investigate further.

I actually have a spare pcb, bought it last year cos I was told it was the problem.

It wasn't, and the shop wouldn't take it back.

I'll try switching that.

Cheers.

 

[mickyg]

ok your number one suspect on this boiler with this fault is probably gonna be the diverter valve. You can access the water components for a look yourself without any tools needed. The white cover just slides straight up and off. The lower control panel lifts up the swings down. You will find the diverter valve motor just left of centre. It will have a thick black cable attached to it, and it will be a black box, held on to a brass fitting with a black clip that might say "ok" or "yes" on it. Pull the cable off the motor, pull out the clip and remove the motor. Have a look at the motor for water marks, and inside the valve where you pulled it off. Should take no more than 5 mins and no tools, and easily put back again. If thats not the cause then look around for general water leaks. After this, then the old favourites, pump, fan and pcb are next.

 

[Antz]

Pump looks ok.

The fuse on the pcb is intact as well.

No sign of water anywhere.

 

[bengasman]

Pump can look great, but still blow the fuse.
Fan would now be prime suspect.

 

[Antz]

Thanks all. I'll try the pump next.

 

[kevplumb]

disconnect the pump/fan/gas valve(has been known) in any order till it stops playing up

dont matter what it looks like as ben said