I've got following setup for heating water:
- solar panel on the roof
The overall setup is simple - the cold water enters the system and goes first through the solar panel and then through the boiler reservoir.
Then, as a last piece there is a hot-water recirculation pump (Wilo Star Z25/2) that creates a circuit in between the cold water supply and hot water out.
However, I do not get any hot water out of the taps, despite the boiler working and pipe leaving out of it being hot.
After very long figuring-out and trying to feel where the hot water goes by feeling all the pipework, it seems like if the water was going through pump in the other direction! There also seems to be a check/no return valve installed on the intake side of the pump.
I am very sorry for the rough description - I do not have access to the plans so I've "reverse engineered" the above.
My total uneducated guess is that the shut-off valve is faulty and allows the cold water back into the circulation.
Also, the pump seems to be broken as well (I believe it has been for a while) - what happens when it breaks? Does it normally allow flow through in the other direction even if not broken?
I've drafted the schema of the system: