What size are the tails? if they are less than 15mm that is your problem
Is the pipe airlocked? if there is a high spot the air will collect there &
restrict the flow.
A crude but effective way of sorting this is to blast the air out with the
The simplest way to do that is to [on the assumption there is a nearby
washing machine] use a washing machine hose, one end to hot washing machine
valve, one end to cold washing machine valve, turn on hot washing machine
valve, then slowly turn on cold washing machine valve.
You should hear the air rushing up to the cylinder. after about a minute
shut off both machine valves & try the hot tap, this may need to be done
There is a danger that a badly plumbed cylinder will rupture under mains
pressure so DO NOT TRY THIS AT HOME. Unless you have an umbrella handy ;-))
Saying that it has always worked for me.
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