Unvented to vented....do I need to change the boiler?

[Soots7t4]

Hi, I wonder if some one could offer some thoughts on the following....we've had a multi fuel stove fitted which has been joined into our existing central heating system. The system was unvented and used a Vaillant Thermocompact 628. The contractor did a great job of fitting the stove but I now have an issue with the boiler.

I had the boiler serviced recently and on completion the service engineer gave me a form stating that the boiler was not suitable to work on an open system and that it was dangerous. He then isolated the boiler...I contacted the stove contractor who told me to get a service engineer that knew what they were talking about, there is no problem with their installation...not very helpful and I'm not sure what to do next...

Could someone please explain why this model of boiler cannot be used on an open system i.e. is the service engineer giving me wrong information or the HETAS approved stove contractor?....

To add to my woes I've been quoted £3,500 to replace the boiler by one well known company and another well known company has said they won't do it because of the stove......

Any advice would be really appreciated. Thanks.

 

[hossacd]

Page 5 of the manual advises the boiler can not be used on an open vented system.

http://www.acwilgar.co.uk/Boiler-Manual-PDF/Vaillant/Thermo compact.pdf

 

[stardanny]

Need more info, photos etc.

Is the stove a solid fuel type, with coal and wood?

Did they fit a feed and expansion tank for stove?

The service engineer is correct, your boiler is only to be used on sealed system.

You could change it to Vaillant 400 series which is open vent boiler, to supply and fit, about £2000.

We need more info first.

Daniel.

 

[petit_pablo]

Had they connected to a thermal store then the boiler could have stayed sealed. Would have cost you much less.

The hetas guys haven't done a good job at all. It might look pretty but they have dropped a clanger there.

 

[Madrab]

I wouldn't be worrying about the cost of a new boiler If I was you. I'd say it's a pretty serious on the installers part not to check that a key component, and you don't get much more key than the CH boiler, is not suitable for the system they are installing.

I mean it was just a case of them reading information that is easily available to them.

I'd say it's clearly for them to correct at their cost, it's called a guarantee. The installation was guaranteed wasn't it? You had a working system before they installed their stove, now you don't, seems pretty clear cut who's liable here.

 

[Soots7t4]

Thank you for your responses, I am inclined to think that I need to take this further, the guys did a great job with the stove but they subcontracted the plumbing part to a HETAS approved person they use regularly..or so they said.

StarDanny, I'll try to get photos uploaded but to answer your questions it's a multi fuel stove and they did fit an expansion tank and feed to it.

I've sent an email to clarify that the HETAS engineer had done his homework and checked the suitability of our system before he started, it is guaranteed so I'll be following up with a more straight to the point request to sort it out. I found the same comments on page 5...seems pretty basic stuff to check for.

Can anyone tell me the technical reason why this type of boiler shouldn't be used for open vent..is it something to do with they way it is designed or more about specific components, the statement on page 5 of the manual is pretty specific but I'd like to be in a more informed place so that they can't pull the wool over my eyes...any responses would be most appreciated.

Thanks, Mark.