Hot water leak and bloackage

[jack]

The oil AGA was not heating the water in the indirect hot water cyl (which I replaced on Wednesday), the feed pipe was barely warm.

The AGA engineer suggested tieing the CWS tank ball valve up to see if there was a leak on the HW side which would explain why the AGA would not heat the hot water.

So I tied the CWS tank BV out of the way at 1130 today, by 1630 the CWS tank was empty, so this is why the AGA does not heat the water. A constant demand.

So I untied the BV and let the CWS tank refill to then look for leaks.

But when I refilled the CWS tank there is a feeble amount of pressure at the hot water tap or shower, which was not a problem before. I am pretty sure the HW cyl is full.

So I reckon there is a partial blockage somewhere on the pipes between the HW cyl and the taps, but no idea about the leak.

There is a new Mira shower valve which does not leak and a Franke mixer tap in the kitchen, the washing machine is cold feed only. so I am mystified as to where the leak is.

I may have dislodged some scale whilst soldering pipework for the HW cyl which has caused the blockage?

Thought about tracing the pipe routings and err I am not sure what next.
Lifting floor boards to look for leaks, although there are no obvious water leaks.

The pipe out of the HW cyl is 22mm and then goes down to 15 for taps so maybe that affects the blockage?

[oldplumber]

Just a thought do you have an air lock in your hot water feed to taps causing poor flow, blow mains cold back through hot via H/Ctaps, kitchen mixer to clear air lock.

does your cws tank also feed WC,s and cold taps hence why empty. Im pretty sure if my cold water tank emptied over a 5 hour period I would have noticed a drip some where.

Are your aga primaries to the cylinder gravity fed? if so you are probably air locked and need to bleed them out to get a flow going and do so pretty dam quick..Also you may want to turn off the aga if you are filling the primaries as it cant help if you are trying to prevent are locks introducing cold water into a rather hot heat exchanger. this may not have happened but I dont know the full story, only thinking of the worst points that come to mind.

[jack]

Thanks Oldplumber for your comments they are appreciated.
By fault finding the leak was under the quarry tiles in the shower room.
The structure of the floor from the top is:
1. Quarry tiles (Ruabon)
2. concrete.
3. scree
4. Concrete.

There is a wide section of DPC that the pipes are laid onto by the wall.

The copper pipes are wrapped in poly and hessian wrap round sleeve which I will replace with what ever the merchants recommend when I phone them tomorrow.
Got to wait for the area to dry out fully before I re concrete.