I turnhot water taps on for 5 seconds and water comes out warm and then after that it goes freezing cold, and suggestions??

Martin Speedie, February 2009

try turning your heating off and start from cold..
does your boiler fire up or make any noise ?
if it doesnt and you can get heating it is likley to be your water flow switch or divertor valve depends what model you have.
if it does make a noise ie fan start or similar then you could be looking at fan pressure switch or if it actually sparks ( heard tick tick) it could be gas valve

tech boilers svs, February 2009