Can I remove these large wall-mounted ventilation boxes?

Terminatrix

Hello everyone!

I own a house built around 1960 and it has these ventilation boxes on the wall. A larger one in the living room, which is wired into the mains (see 1st pic below) and blows fresh air into the house. And then 3 smaller units in the bedrooms that are mounted higher up and don't have any wires or switches (see 2nd pic).

I assume that back in the day, they were just an alternative to opening a window and allowing fresh air in?

Could I simply remove them and place a ventilation grill over them? Does anyone know why the smaller bedroom units have no visible wires or switches? How would they work?

Thanks in advance!

FreeBear

Do you have any open fires (gas, wood/coal) in any of the rooms ?

If so, you should have some ventilation from outside to prevent the build up of carbon monoxide (CO). If there are no fires, I'd personally block off the vents as they would be a source of cold draughts and annoy the heck out of me.

Alderbank

I can't see your pictures but they do sound like PIV (positive input ventilation) units, probably Drimasters since these have been around for 50 years or so. They are usually regarded favourably by users as being effective in eliminating nuisance condensation within a property.

The bedroom ones without user controls are controlled by sensors and draw dry air in from the loft space where it has often been warmed by solar radiation on the roof tiles or heat leaking from ceilings. The claim is that this delivers a bit of 'free' heat to the bedrooms.

Section62

Terminatrix said:

Could I simply remove them and place a ventilation grill over them? Does anyone know why the smaller bedroom units have no visible wires or switches? How would they work?

You might want to get an electrician in to make sure they are all safely disconnected from the mains.

The bedroom one looks like there is a part already removed from the underside which could have been where the electrical supply entered, but an alternative is the supply could enter the unit from the rear via a cable in the wall.

There is no indication they provide heat, but if the removal process reveals a gas supply as well then this needs to be disconnected by a gas safe engineer.


The other thing to be careful of is this is the kind of equipment and era where asbestos ropes and gaskets were commonly used for sealing things.  Whether you do the work or get someone else to do it for you, you need to be aware of a potential risk of there being asbestos present, and what precautions you should take.

edgex

Well, Airprime went bust in 1982, so I doubt the thing has been serviced for quite some time. Does it still work?

You still need ventilation, there's standards for it;
https://www.gov.uk/government/publications/ventilation-approved-document-f

Are there 'trickle vents' on the windows? Is there an extractor fan in the bathrooms?


Are you in a radon gas area?
https://www.ukradon.org/

Another_Level

Seen those ventilators in a lot of council / la properties. sometimes near busy roads,airports & or pollution  .  There is a reason why they were fitted instead of a standard cheap air brick/grille.

As already mentioned they may contain some type of asbestos.  

Fitting a new ventilator with draught baffles will reduce wind blasts entering the room, giggle 'stadium blackhole' 

  

Terminatrix

Thanks for everyone's replies so far. A few more details...

There are no open fires in the property but there probably was one in the past, since the old chimney exists (blocked & vented).
The living room unit still works and just blows in fresh air when switched on.
These units only use electricity (not gas). It is possible (and quite likely) that the bedroom units have probably had the wire removed.
The windows are double-glazed but do not have trickle vents. The bathroom has an extractor fan.
I'm not in a radon gas area but am very close to Heathrow airport (1 mile).
I don't recall seeing any of these units in neighbouring homes, so I suspect that over time, they have just removed them and placed a vent over the hole. But as the property is rented out, it seems like I would be better off replacing the whole unit with something like the Stadium Black Hole Core Vent (as Another_Level suggests), to prevent tenants from blocking it with tissues!! 

Section62

Terminatrix said:

...but am very close to Heathrow airport (1 mile).

So possibly provided because airport noise means opening windows for ventilation is not an option?