Boiler installer left old flue hole open

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Hi, I recently had a gas boiler replaced in a 2nd floor flat. In discussions with the company afterwards, I found out that they had to drill a new flue hole (I wasn't there when the work was being done - it didn't seem like they would have taken the initiative to tell me!). This hadn't been planned - the possibility that this would be necessary hadn't been discussed beforehand. From the outside, the old flue hole appears open (see image) - they've not told me yet if there was any sealing done on the inside. The hole is covered over by the boiler, so it can't be seen from the inside. The cupboard where the boiler was installed is a tight space with only just enough clearance, which is why I think the position of the flue needed to be changed to fit the new boiler. I'm also going to have to discuss this with my freeholder, as I think their permission would normally be needed beforehand for changing a flue hole.

I was wondering is it acceptable for the old flue hole to have been left like this? And is it reasonable for the installers not to have raised beforehand that the need to move the flue hole was a possibility given the amount of available space, given there is not generally freedom to drill through external walls in a leasehold flat? Is it urgent to get the hole repaired, or is it not a big deal if it's left like this for a few weeks? Does anyone here know what would be the most cost-effective approach to getting the hole repaired?

Thanks very much to anyone who can help.

IMG_1814.jpeg
 
Not acceptable at all, leaves Cavity open to ingress of Birds, Wasps, Bees, anything in fact that takes a fancy to making a home in there, never mind the weather.

Have an idea the new Flue needs to be sealed externally as well, but hopefully one of the Gas Safe Guys can confirm that.
 
Have an idea the new Flue needs to be sealed externally as well, but hopefully one of the Gas Safe Guys can confirm that.
Yes it does because it's an opening in the building, so similar to an air vent, most mi's I've read state 300mm away, which that clearly isn't. There’s no sealing around the outside if the flue and no weather collar.

Also the flue could be considered too close to the eaves and eaves ventilation and possibly the window, but that may be ok. A lot depends on the manufacturer of the boiler, perhaps @fyj can confirm this?
 
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Yes it does because it's an opening in the building, so similar to an air vent, most mi's I've read state 300mm away, which that clearly isn't. There’s no sealing around the outside if the flue and no weather collar.

Also the flue could be considered too close to the eaves and eaves ventilation and possibly the window, but that may be ok. A lot depends on the manufacturer of the boiler, perhaps @fyj can confirm this?

Thanks. Do you mean it currently doesn't appear compliant with regulations if the new flue isn't sealed? What does it need to be 300mm away from?

The new boiler is a Vaillant Ecofit.
 
Do you mean it currently doesn't appear compliant with regulations if the new flue isn't sealed?
If it’s not sealed inside or out, then no it doesn’t. Should be sealed to the building fabric, but mi’s will stipulate what they want.
What does it need to be 300mm away from?
Any opening to the building, such as an air vent, ventilation, holes et al. The flue should be 25mm away, might be more from the soffits, again would be in the mi’s.
 
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If it’s not sealed inside or out, then no it doesn’t. Should be sealed to the building fabric, but mi’s will stipulate what they want.

If it's sealed on the inside alone, would it be compliant with regulations then? Does it only need to be sealed on the outside if the "mi's" say so?
 
Thanks. Sorry but just to check, what are "mi's"? Manufacturer's instructions?
Sorry should have said, yes manufacturers instructions
If it's sealed on the inside alone, would it be compliant with regulations then? Does it only need to be sealed on the outside if the "mi's" say so?
I can't remember tbh, there was a gas safe technical bulletin regarding being sealed to the building fabric. I'll try and find out. It should have a weather collar though and still doesn't negate the fact of the hole.
 
If it's sealed on the inside alone, would it be compliant with regulations then? Does it only need to be sealed on the outside if the "mi's" say so?
Screenshot taken from the mi's, steps 2 and 4 should answer this
 

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what is the white pipe sticking out the wall is this from the boiler ?
 

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