Thermostat probes gen.

[x-z]

Thermostat probes are inside a junction box that is sealed with a screened opening to allow
air circulation

Термобаллоны термостата находятся в распределительной коробке герметизированной .... ?????

[johnstephenson]

Here are some examples of screened openings (screened vents):

* http://www.google.co.uk/imgres?imgurl=http://i.ebayimg.com/00/s/MTAyNFgxMDI0/z/og4AAOSwZtJW9Wk4/$_35.JPG&imgrefurl=http://www.ebay.ca/itm/Ideal-Air-Screened-Wall-Vent-12-inch-12-NEW-/201548855753&docid=G1Gn1e25qEj4dM&tbnid=dkommeMobgnc8M:&vet=1&w=300&h=300&itg=1&bih=512&biw=360&ved=0ahUKEwjvu4DeyOLQAhUhCsAKHTJ4BrcQMwhUKDAwMA&iact=mrc&uact=8

* http://www.google.co.uk/search?site=webhp&tbm=isch&source=hp&ei=UUFIWNz1B8T6Ur-2rLAJ&q="box"+"sealed"+"screened+opening"&oq="box"+"sealed"+"screened+opening"&gs_l=mobile-gws-hp.3...2711.26495.0.30270.34.34.0.1.1.0.209.4687.0j33j1.34.0....0...1c.1j4.64.mobile-gws-hp..0.21.2814.3..0j41j0i5i30k1j0i8i30k1j0i30k1j30i10k1.4m8s0sEaUTE#tbm=isch&q="screened+vent"&imgrc=wEB_HWLhihBWrM:

* http://www.google.co.uk/imgres?imgurl=http://www.ridacritter.com/Images/gallery/mice/mouse-entry-into-house-college-park-ga.jpg&imgrefurl=http://atlanta.ridacritter.com/mouse-control-atlanta.php&docid=oMPOjHO6YBh87M&tbnid=hIZbd20cMg-B4M:&vet=1&w=600&h=450&bih=512&biw=360&ved=0ahUKEwjvu4DeyOLQAhUhCsAKHTJ4BrcQMwgoKA4wDg&iact=mrc&uact=8

So they're openings/vents with a mesh or slats across them, designed to keep animals, birds etc out but allow air in.