window glass scratches?

27 Sep 2007
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United Kingdom
I have recently had some upstairs windows installed which were fitted with ‘k glass’. All appeared ok until two days later one of them was misted up on the outside pane due to it being a cold morning and there being a boiler flue underneath. The misting revealed what appears to be scratches over the whole of the outside pane, although it is difficult to feel anything by hand. On cleaning, the window appears fine but if left for several days dust seems to settle in the scratches which then become visible again. Also, in heavy rain, the water appears to run down the channels created by the marks. The remaining windows were tested using a kettle and found to have the same results.
The installer is now going to turn the panes around as he says the coated glass is on the outside pane, (albeit on the inside face), and this should cure the problem. However it is my contention that the coating may be on the external face of the glass and this has been damaged when cleaning the windows after installation. If this is the case then dust would still eventually settle and the marks reappear. Even if this pane is normal glass surely the same results would occur.
I have attached a photo and any advice as to what this may be would be appreciated.
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Are you saying these so called invisible scratches are only apparent when the glass is misted up?

Sounds to me like you are moaning over nowt and that these 'scratches' are just wipe marks.
I doubt very much they are scratches, they just want a good clean not just a quick wipe the installers do when they're rushing to finish the job. Don't turn the units round either, although it wouldn't make much  difference they are designed to work best when fitted correctly, the outer pane steaming is normal and shows the unit is working, the dew or condensation is just highlighting areas that haven't been cleaned very well, it's common also to see where the glass sticker once was or circular marks from the glass suckers used when transporting glass way back at source
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Sorry I misread the post, if the units are the wrong way round then yes get him to turn them, I wrongly assumed he was going to turn them because the he thought he maybe fitted them the wrong way round and this was causing the outer pane to steam
Thanks for the replies. The windows have been cleaned several times and initially appear ok. However, after several days what I presume is dust seems to settle in the same marks and they become visible without steaming. Also, when raining, the water seems to run down the same channels. Please note I understand that condensation can occur with these windows but that is not my problem. I have other windows with the same glass from about 5 years ago and do not get any marks if condensation is present.
Tried mailing pilkingtons last week but no reply.
Thanks again for the replies.

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