Boiler permanently swicthed on - Help!

[SteveBate]

I have a serious problem somewhere in my central heating. This morning at around 04:00am I awoke to find both my heating and hot water switched on. I went to look at the controller - a Sunvic XL 207 - and sure enough both red lights were on. The digital display however is completely blank. There is no information being displayed whatsoever and even worse, none of the buttons are responding. I cannot turn off either the heating or the water.

The boiler is one of these: http://www.avantaplus.com/index.php?content=24s and was fitted 2 years ago.

However, the Sunvic XL 207 is the third one in that time. The previous two stopped working on the heating side though the water would still work. Now, this one having only been fitted 3 weeks ago is giving me a new problem i.e. turning on both heating and water and not allowing me to turn them off.

I am at a complete loss as to what the problem might be. Could it be a wiring problem? Surely these Sunvic controllers should last a little longer than they have done?

There is a wire coming out of (what I think is) a 3-port mid position valve (made by honeywell) that goes to the Sunvic. Could it be this valve?

More pressingly, I need to turn the boiler off. Will I do any damage if I just flick the mains switch next to the boiler?

I am desperate for some pointers. Please help.

Thanks

 

[bengasman]

you can for the time being make sure your cylinder stat is set correctly and turn your roomstat lower when you don't need the heating.
all wires from any part should go to a wiring centre, not directly to each other, sounds like someone has been cutting corners

 

[Azazel]

Hello,

Firstly you will not damage anything if you turn the switch off at the side of the boiler. This should electrically isolate all the components in your house that are to do with the central heating. (programmer, motorised valve, boiler)

Secondly I assume that you have not changed the programmer yourself?

If thats so, why not get whoever changed it for you back? Especially if its only lasted 3 weeks.

However if you have changed it yourself, then why not contact the person(s) you have bought it from. It will still be under warranty as its only 3 weeks old.

I don't imagine the wiring to be at fault. As your heating/hot water must have been working correctly the previous 3 weeks? Although thats only a guess, because I can't say 100% without seeing the system wiring.

Perhaps it time to have another brand of programmer. I like the Drayton Lifestyle range of programmers.

Hope that helps.

 

[SteveBate]

Thanks for your responses.

@ bengasman:
It appears that my room stat is having no effect whatsoever after having turned it as low as it will go. Could this be part of the problem?

@ Azazel:
As for the fitting of the controller, well it was wired up for me at the time the system was fitted but I replaced it three weeks ago but it only clips onto a backing plate (I'm sure you know) so I don't think I could have messed up anything there (though you never know!).

Each time the controller has been replaced the system has worked correctly in the beginning. The first one lasted about 12 months. The second nearly the same but this one, three weeks!

Somebody else recommended the Drayton to me a while back but I believe it required the wiring to change and I decided to just get a straight replacement. If I'm going to have to call someone out then I think I'll ask them to fit me one.

 

[D_Hailsham]

The Honeywell Wiring Guide has step by step instructions for diagnosing faults in programmers, thermostats, motorized valves etc. They can be applied to virtually any make of equipment.

If you have a multimeter, you should be able to identify the faulty component.

If you do not have them, here are the Sunvic 207XL Installation Instructions

 

[MANDATE]

Steve! I note in the instructions, it mentions pressing the reset button using a non metalic tool. I know you said non of the buttons was responding, but you didn't mention the re-set button in particular.

 

[bengasman]

if your roomstat has no influence, it IS part of the problem