Viessmann boiler expert(s) wanted

[mangocrazy]

I have a Viessmann Vitodens 300 boiler fitted to my house in Stafford. It was fitted in summer 2003 and has been reliable for the most part. It's needed a couple of gas valves and a few years back it needed the control module - very spendy. I kept the faulty one, intending to hand it over to a friend of mine who is a bit of an electronics whizz, to see if he could find out what failed, fix it and thereby have a backup if the current one failed.

However actually getting at the circuit board has so far proved to be an impossibility. It has a plastic shroud on the back with lots of plastic clips and a couple of screws holding the cover in place. I can get three quarters of the perimeter of the cover loose and able to be withdrawn, but one corner stays stubbornly stuck and immovable. I don't want to apply brute force and ignorance, so was wondering if anyone knows how to remove the cover. I suspect there is some kind of jig or special tool involved. Either that, or a hidden screw.

Part 080 is the item in question:

https://viessmanndirect.co.uk/Boilers/7176539/Control

 

[Barking Mat]

Ouch £500.

I'd be looking for a dremel and being very careful cutting it open.

 

[sg66]

The instructions in the manual say drop down front panel and remove rear cover, lots of clips around plastic but can't see anything hiding, no real reason to make getting at the pcb difficult?

 

[Kayos]

As a heating engineer, brute force is exactly what you need

Also, reliable and needed a couple of gas valves plus a module is a contradiction of terms

 

[mangocrazy]

As a heating engineer, brute force is exactly what you need

Also, reliable and needed a couple of gas valves plus a module is a contradiction of terms

In nearly 20 years of service?

I'll use brute force if there really is no other way.

 

[Seadog]

My boiler was fitted in 2006. Apart from a problem recently, dry joints on the ignition module, it has been faultless. Two gas valves and a pcb are not what I would term "reliable."

 

[mangocrazy]

My boiler was fitted in 2006. Apart from a problem recently, dry joints on the ignition module, it has been faultless. Two gas valves and a pcb are not what I would term "reliable."

What make of boiler was that? In comparison with another ch boiler I've had experience of, this one has needed far less intervention, albeit it's been expensive when it has.

But then the 'other' boiler was a Keston Celsius...

 

[mangocrazy]

The instructions in the manual say drop down front panel and remove rear cover, lots of clips around plastic but can't see anything hiding, no real reason to make getting at the pcb difficult?

Getting the module itself out is straightforward, but getting at the pcb is a different matter. The module is replaced in its entirety - it appears that Viessmann don't want you getting at the pcb. It's certainly not available separately.

 

[sg66]

Sorry a thought you were on about plastic cover on rear

Have a look in the service pdf should tell you what to remove, pcbs often held in by a mix of plastic clips/screws and control knobs can grab.

 

[sg66]

Couple of parts over 20yrs is hardly unreliable, use, location, servicing can all play apart but sometimes parts fail, I worc make some incredibly un reliable boilers if we're using the part list above

 

[Seadog]

What make of boiler was that? In comparison with another ch boiler I've had experience of, this one has needed far less intervention, albeit it's been expensive when it has.

But then the 'other' boiler was a Keston Celsius...

Ravenheat.

 

[jenki]

Glued? perhaps, I am about to attack a mobile phone with initially a hair dryer you tube shows them using heat guns.

 

[Seadog]

Good luck. I wrecked last mobile trying to remove the armoured glass

 

[mangocrazy]

Sorry a thought you were on about plastic cover on rear

Have a look in the service pdf should tell you what to remove, pcbs often held in by a mix of plastic clips/screws and control knobs can grab.

I've looked in the service manual and there is no mention of dismantling the control module. It's just the one part comprising front, back and pcb, none of which are available separately. Here are photos of the front and back:

The part that is resisting all my attempts to remove it is around the on/off button (so bottom left on second photo). The other edges can all be freed by pressing the little plastic clips.

 

[jsf55]

Is that a fuse holder on the bottom left that needs pulling off first ?

 

[sg66]

Ahhhhh I'm with you now I take it they supply the whole thing including housing as a replacement.

Could be glued, clipped anything, would start at point that has most movement and work away from there look closely at any points where it's not moving.

 

[mangocrazy]

Is that a fuse holder on the bottom left that needs pulling off first ?

It is a fuse holder which unclips easily but doesn't appear to aid removal of the larger assembly. Good spot though...

 

[Seadog]

Check that there isn't a hidden screw under the part number label. Its a favourite trick of manufacturers.

 

[mangocrazy]

And today's star prize goes to @Seadog . An innocent little bar code sticker hid a secret - a torx screw underneath. It's a bit late to dig out my torx drivers tonight, but will report in the morning.

 

[Seadog]