vented hot and cold feeds

[bass]

fitted bath mixer tap (single lever) in one of two bathrooms both consisting of bidet w.c bath and basin. drained f/e tank which feeds both hot and cold in both bathrooms and when filling back up noticed water pressure not the same on both hot and cold in same bathroom. went in loft and noticed three tanks (one central heating) and two for cold and hot feeds.one tank has the ball valve feeding as normal but second tank gets fed via feeds to hot water cylinder(two 22 fromf+e tanks teeing into 28mm pipe) feeding cylinder. the pressure in other bathroom is fine (did not drain tanks from this bathroom. I suspect the system is air locked and tried backfilling from downstairs washing machine connections without any joy. I am after any advice as i have no hair left. I also checked for any crap in taps.Would i be better draining system again on both sides and leaving mixers in central position when filling up? I am asking the question for pointers as this is going to cost me money independantly backfilling all feeds .

 

[BournemouthPlumber]

... i think you may need to clarify the position before anyone can reply.

F&E tank usually refers to the small feed & expansion tank used to feed the vented central heating system.

Ignoring the central heating F&E tank:

You say the second tank gets fed from feeds to the DHWC - does this mean that where the first CWSC feeds down to the cylinder - these pipes are tee'd off from to feed the second tank?

Does the first CWSC supply the cylinder and the second CWSC supply the non mains cold taps around the property?