Sime Format C Combi Boiler - PCB problems?

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Hello guys,

My combi bolier isn't working correctly and it is only 17 months old.

When I turn the thermostat up, nothing happens. It only seems to work when I manually turn the selector switch summer/winter to "gas flame" position. Even then it runs for approximately 10 minutes and then cuts out. The fault finding indicator flashes bi-colour orange and this seems to indicate insufficent system pressure. However, the pressure is fine - 1.5 to be exact.

On further inspection, I opened up the front panel to inspect the PCB control board and found some black suity material. It appears that a transistor may have blown. On making a temp circuit to bridge the gap between the transistor points, to test if this is case, the boiler kicks into action.

I have a few questions and hope someone can help.

Have I diagnosed the correct fault?
Do I need to purchase a new PCB board (hope not)?
If I don't need to replace it, can it be soldered?
What caused this to happen to a new boiler?

Cheers,

Big Yin
 
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Doesn't look like a transistor...appears to have only two pins. You sure it's not a fuseable link that's blown or a rectifier. Either way you should not be linking it out.

The cause for failure should be found (ie any faults with the other boiler components) and a new board obtained. You can't just swap the board...ignition and heating pressures need to be set.

Have you contacted Sime or the origional installer? Don't know what the warranty is on these.
 
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For a start thats a two terminal device whereas a transistor is a three terminal device!

Then I thought that a Sime Format C was a non condensing boiler about 10 years old?

Burnt components on a PCB are often as a result of faulty external components.

As you probably want to "save money" by buying and fitting a replacement PCB yourself, just how would you feel if you watched the new one burn up in the first 10 seconds after you powered it?

Tony
 
Thank you for the quick replies. There doesn't appear to be any surge protection on the outside of the boiler. It looks like the power to the boiler is coming directly from the mains. :eek: This cannot be right? Could this be the cause of the problem?

...it appears that diode had blown rather than a transistor. My mistake.

Sime technical support is only open mon-fri. It had a one year warranty. I've tried phoning the installer but to no avail - non return of phone calls.
 
Is it a condensing boiler?

What do you think that Sime can tell you that we cannot ( better ) ?

Tony
 
That's sime for you, and the installer is quite happy to fit a load of shyte but not to fix it. :rolleyes:
 
If it's under guarantee wait until Monday.

Surge protection isn't usually provided for a boiler.

If the manufacturer cosidered it a risk they could design it into their pcb's. There are these blue disk shaped things in sensetive equipment which clamp down spikes.

Who knows what has happened?

Tony has warned if there is a short circuit item in the boiler next pcb will be broken also.

So fan pump solenoids motrised head (if one) need their windings checking in respect of insulation resistance to ground and resistance of coil length compared to known normals.

it could be simply a matter of changing the diode. It could not.
 
I have repeatedly asked if this is a condensing boiler but the OP chooses not to reply.

If its not then its the wrong boiler to have been fitted. Even Sime have a two year guaranty on their Band A boilers.

Whilst another component on the PCB could have failed and blown, that burnt component it is very likely to be damaged by something else in the boiler at fault.

Tony
 
Hi Tony,

I mentioned earlier that it was combi. Why would it be the wrong boiler to be fitted?

Cheers,

Victor
 
AFAIR the requirement for condensing boilers in Scotland became mandatory on the 1st May 2007 so there was no need for your boiler to be condensing.
 
Hi Tony,

I mentioned earlier that it was combi. Why would it be the wrong boiler to be fitted?

Cheers,

Victor

We know that it is a combi but we dont know if it was a condensing combi. As Geof has pointed out if it was fitted after 1st May 2007 it should have been a condensing boiler.

Tony
 

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