You appear to be repeating yourself - this was the answer I gave to your first...
You need to say more Tammy.
What sort of boiler make & model ?
What's happening when it goes hot cold hot cold ? Running a kitchen tap or the bath.
There are some smart cookies on here who may be able to help you - put in another question with the boiler type in the title line.
Good luck...
Peccavi, March 2013
