No hot water to downstairs bathroom

simo28

Hi, looking for some help with getting hot water to a downstairs bathroom problem that is wrecking my head.

Background is the hot water tank was downstairs but buried behind the kitchen cabinets so I had that moved upstairs. While doing that I decided run the pipes differently to how they were installed when I bought the house. The flow of the water was originally going from the downstairs tank up to the attic across the attic floor and down to the upstairs bathroom then back up out of there to the attic, back across the attic before going back down to the downstairs bathroom. What I was finding was that there was minimal pressure in the hot tap in the upstairs bathroom but that while the pressure was fine downstairs it took a while to get going due to the distance it had to travel I assume.

Right so now I've changed it I have the water from the tank upstairs to the attic and across and down to the upstairs bathroom. This has improved the flow greatly. Its not brilliant but its ok.

For the downstairs bathroom I have it coming from the expansion pipe and across the attic (about 20 foot) and then it drops down. There is no flow at all and it is driving me mad as I just did up the bathroom and its pointless without hot water. I have an access point to the pipes downstairs and I have swopped the hot and cold around and when the cold is set to the hot taps it comes out fine so I'm guessing the problem is behind that point.
Can anyone offer advise here or perhaps recommend a plumber who is savvy with this kind of thing.

Hyina

Why is downstairs running from expansion pipe and not just t'd of from upstairs supply?