How can I fix low water pressure from loft storage tank?

Question

Since removing all pipes from our loft storage tank in order to replace the deck it was on and had soaked, I've successfully reconnected everything and fixed the leak in the tank. But now the water pressure from cold water taps upstairs is much less than it used to be.

Could there be a bubble in the pipes now? Do I need to flush that out somehow?

I should add, for the troubleshooters, that the tank is in exactly the same place as before, with the same pipes (unmodified) and as high as it was before. I replaced the boards that made the "deck" and reconnected the same pipes. The tank is as full as it was before (a lot of water in there).

Answer 1

Given that the tank position etc. is the same the most likely explanation is that you have a blockage or narrowing somewhere in the pipes - probably from some sediment you dislodged while removing the tank.

Is it just one tap, all the upstairs taps or are the kitchen taps also affected?

If it's the latter then the obstruction will be nearer the tank before the pipes split. If it's the former then the obstruction will be after the split or (more likely) at the tap itself.

If there's nothing blocking the affected tap(s) then you will need to flush the system somehow, but it will depend on what's causing the obstruction. You might be able to clear it by emptying the tank again, leaving the taps open and then using a hosepipe to force water through the pipes - but if it's a piece of grit this won't really help.

If the taps have a filter on their outlet then you could try removing that and cleaning it. Before replacing the filter run the tap to see if that dislodges anything, this might dislodge any grit.

Answer 2

You might try disassembling the tap in question - it could be that something from the tank is now lodged in the tap itself (either in the valve, or in the spout). It might be further upstream, but I'd start with the tap.