blocked(?) hot water system

[sprig]

first post - seeking advice
3 level home with mains pressure HWS on lowest level.
all outlets are pretty well vertically above HWS on levels 2 and 3
hot water is generally unwilling to flow at any pressure unless able to turn nearby cold outlet on/off quickly, whilst hot outlet is on (but only dripping)
is this likely to be result of air getting INTO the system? if so, any suggestions on what to do to get it / keep it out ?
many thanks

[wonderplumb]

Check; Tempering valve if fitted, isolation valve on the inlet, wether it be a duo valve or seperate isolation and check valve, whats your normal water pressure like? Sounds like a valve/ancillary problem.

[sprig]

Thanks for suggestion. HWS is hard to get to - but I now know we've no tempering valve; but a Reliance isolating / NR valve on inlet followed by expansion control valve. Normal water pressure has always been good. Not sure how to check, but have turned NR on / off, and released some water thru chekc valve, so will see how we go. Thanks again.

[sprig]

Just to close the loop on this post ... it seems this problem caused by the non-return valve setting ie the NR valve was fully open (problems, incl much hammer when cold water turned on/off) but when I wound it back 1/4 and all seems fine. Not sure if the "fix" actually related to the problem, but we're enjoying hot water again. Thanks wonderplumb.

[Brickie]

Plumbers were around long before Jesus was a carpenter

So were hookers..

[wonderplumb]

Probably before pubs too, so you need a nerve settler after a days work