Hi,

I have no hot water coming out of the bathroom sink or bathtub. Hot water in the kitchen is absolutely fine.

I guessed it may be an air-lock in the hot-water system (or some crud build-up). To fix this, I linked the mains coldwater washing machine feed into the hotwater feed and let that run for a few minutes.
This works OK, and I do get hot water in the bathtub and sink - however, it only lasts a few days at a time before I have to go through the same routine over again.

I did notice that there is an overflow from cylinder tank to the feed tank which is filling up when I backfire the mains into the hot water pipes. Do I need to block this overflow to completely get rid of the lock, or is there another problem.

Could really do with some help here.

Thanks,
Harvey

Are all valves completely open? Have you checked areators for debris?

Yep, checked the valves are open.

The other thing to note is that the differnece in height between hot water tank and sink taps is about 1metre.
Could that be something to do with it - although I think not because it works for 48 hours at a time.

When you do the flush, what kind of crud comes out?