Hello my name is Carl. This is my problem. Once or twice a week I lose hot water pressure,it slows down to a trickle. If I open and close the kitchen tap quickly sometimes that helps. A loud clunk is made and the hot water returns to normal. Any ideas?

Once or twice a week I lose hot water pressure,it slows down to a trickle. Would this involve the entire house or just one faucet?
If 5t6he entire house's affected then I would check the water heater inlet and outlet for heat trap nipples,(see image). If you have them installed replace them with 3/4" brass nipples. Good luck, Tom