Help needed - Plumbing issue!

[Stargazer87]

We're currently doing up our nursery and my husband removed a radiator from the wall to paint behind it, all seemed to go well until he put it back on and reconnected it...we now have no hot water! Any ideas what might have happened and how to rectify it?! 🤷🏻‍♀️

[PigletJohn]

the water that was lost when the radiator was taken off has not been replenished.

What colour was the water in the radiator, and how much sludge came out?

Do you have a hot-water cylinder? What colour?

Does your boiler have a pressure gauge?

how many water tanks are in your loft?

How old is the heating system?

[Stargazer87]

The water was slightly yellow and smelt bad, no sludge came out though. We have a Vaillant boiler and its current showing an error message F.75? Does any of that help?

[PigletJohn]

Do you have a hot-water cylinder? What colour?

Does your boiler have a pressure gauge?

how many water tanks are in your loft?

How old is the heating system?

[PigletJohn]

when you find the pressure gauge, I think you will find the pressure reading is below normal and so it needs to be topped up.