Technical

I have just opened a brand new, never used Dwight D. Eisenhower locomotive. On first steaming I managed to get it to run for a very short time, but a lot of water came out of the water overflow into the tender areas behind the coal as it heated. The water then seemed to have run out, as the alarm when on and heating stopped. On a second time around, after letting it cool and refilling it, on heating again the water overflowed into the tender area behind the coal, and then a constant steam of steam from the water overflow. I do not get steam popping from the safety value at all, barely a wisp of steam from time to time, it just steam from this water overflow until it runs out of steam and then when the water runs out the alarm goes off and it is time to cool and back we go...

Any thoughts? This is my first foray into Hornby's live steam, but this is definitely not right...