By Runner44a
United Kingdom 
Hi...I've just bought a small Acer & re-potted it using ericaceous compost in a bright but not full on sunny part of our deck roof terrace. It's relatively sheltered from wind. Since re-potting the Acer, an 'Orange Dream' variety has gone from largely yellow green with a hint of orange on tips of leaves to mainly orange/terracotta colour. Some of the smaller leaves have also shrivelled & dried up. I have watered well but not over done it. All this has happened within a week. Are things ok?
15 Jun, 2014
Answers
So long as you have it in a pot with holes in the bottom, and you don't leave the plant sitting in water in any outer tray, you can't over water, so water more, but remember to empty any tray or outer container after 30 minutes or so.
The colour change might be because of water shortage (early autumning) or it might be the natural change that takes place over the growing season with this variety.
16 Jun, 2014
Hi - was it from Morrison's? I bought three a couple of months ago and they're doing really well! I put mine into 4" pots and didn't bother with ericaceous compost. They're in a very sheltered corner protected by larger plant pots, but I've done nothing else other than water them when we've had a couple of dry days.
You know your roof but I would suspect that it may not be as sheltered in plant terms as you think and it may get that extra bit of sunshine which coupled with a drying wind is just deadly to tender baby plants.
15 Jun, 2014