Externally vented cooker hood?

blackstar

Hi alll

I had a post up not long ago about getting my kirchen cooker hood external vented.

its now getting done.
I have noticed two things and would like advice on this and how to solve.

1) escape of air blowing out the ducting pipes where it's not flush connected due to wall socket being in the way. The escape of air is where the white ducking meets the black pipe at the back, it is not straight and flush as socket on wall prevents a total flush fit. What sized flue would I need? The ducking is 150mm

2) Flue needed to prevent the kitchen fumes blowing downwards towards back door and window, especially when wind blows a certain direction. So please ask the guys to bring one tomorrow rather than have to come back. Please see the vent for it above lights. The white vent.

Two other pictures are not needed but just show how they have run the ducking. The only possible option really.

grumpy_codger

What do you mean by "flush connected"? Usually it's an adapter that fits a standard ducting pipe. 
Is the electric socket switched? If it's not, how are going to unplug the hood if needed? It would make more sense either to move the socket a little or add a fused switch and hardwire the hood into the existing box (ETA: or replace the socket with a switched fused spur and hardwire directly into it?). 
Also, for the vertical part you could use rectangular ducting with round-to-rectangular adapters. This creates a gap for the socket and the plug.

blackstar

At the moment it resembles the leaning tower of Pisa 

blackstar

Wpuld this work in terms of amps etc?

Also better this one or one without a switch?

https://www.toolstation.com/mk-13a-spur-unit/p44377

grumpy_codger

In terms of access side switch is possibly better, e.g.

 

In terms of amps - replace the fuse with the one from the plug. Most likely it's not 13A.

ETA: this one is 'low profile' -

FreeBear

So they replaced the surface mounted socket with a recessed back box. Why didn't they take the opportunity to move it over by a couple or three inches... Get it done properly, and the plug won't be pushing the pipe out. And when done right, a thin bead of silicone sealant between the black & white parts will fix any air leaks.

As for the vent, this one would have been much more suitable -> https://www.screwfix.com/p/manrose-flap-vent-white-125mm-x-125mm/59530 (other sizes available) - When the wind is blowing in the wrong direction, the flappy bits will stop a breeze coming through. Will also stop rain getting in.

WIAWSNB

blackstar said:

I have noticed two things and would like advice on this and how to solve.
1) escape of air blowing out the ducting pipes where it's not flush connected due to wall socket being in the way. The escape of air is where the white ducking meets the black pipe at the back, it is not straight and flush as socket on wall prevents a total flush fit. What sized flue would I need? The ducking is 150mm. Could you clarify - ideally with pics - where this joint is, please?

2) Flue needed to prevent the kitchen fumes blowing downwards towards back door and window, especially when wind blows a certain direction. So please ask the guys to bring one tomorrow rather than have to come back. Please see the vent for it above lights. The white vent. I don;t think this will be the problem you imagine. Usually, once vented out, the smells will dissipate quickly in any slight breeze.

Two other pictures are not needed but just show how they have run the ducking. The only possible option really.

Bits in bold above.

If you look at the bottom of this white pipe, and check the gap between it and the wall, that'll tell you if the FSU you linked to will be suitable. You'll likely need around 15mm.

Fitting a FSU won't be an ideal solution, as the switch could be awkward to get to, and the pipe may need removing should the fuse blow. But, in practice this is very unlikely to occur, so, yes, it's the easiest solution for you. Grumpy's low-profile version in his post will be better again. 

And you just replace the fuse in it for a 3 or 5A jobbie - read the hood's instructions, and go by what they state.

What type of ducting have you run from this round pipe one to the wall?

Mr.Generous

I presume the ducting is covered with a stainless chimney? If so very easy to change the ridgid pipe to a flexi pipe, this could allow access to the plug and seal better. They DO need an adaptor to fit the hood every time I've used one.

Under £4 from Toolstation.

The adaptor looks something like this

Under £2 at Toolstation

Hoods are always best vented, gets rid of condensation as well as smells. Best tip is turn it on a few minutes before required and leave it running 5 minutes after finished.

WIAWSNB

You could even mark the contact area on the duct adjacent to the plugtop, rotate the pipe, gently apply a blowtorch, and press a suitable indentation into it.