water problems -sterling eccles ruby 2010

Adygolfman

Bought in Nov and having two problems.

1. Hot water only runs for 1 min then goes cold.

2. Only uses half the aqua roll then water stops.

Anyone else had these problems? - not getting anyway with delaer - they just said re hot water problem 'do not run the hot tap on full' -but this does not seem right. Must say the thot water tank does seem small. Thanks.