What could be causing this noise in the tundish?

[Lawsofpower]

Hi all, anyone know what could be causing this? Everytime I flush the toilet the (what I think is called) tundish makes a gurgling sound. I live in a flat and sometimes when the people upstairs flush too it can be heard. I had a similar issue about 4 months ago whereby it was leaking due to the washing machine and kitchen taps being a bit clogged, got it cleared by a plumber but now I’m a bit worried about hearing it again when I flush. Anything I should be concerned with or that can be resolved if needed, without a plumber? The toilet is very old so not sure if it’s something than can be fixed if I replace it completely?

 

[ShaunCorbs]

Would contact a g3 engineer as that install of the cylinder doesn’t look / meet regs / correct

 

[Lawsofpower]

Would contact a g3 engineer as that install of the cylinder doesn’t look / meet regs / correct

Hi Shaun the installer was a g3 certified engineer

 

[ShaunCorbs]

Hi Shaun the installer was a g3 certified engineer

You sure d2 doesn’t comply with regs tundish to bend minimum 300mm yours looks less than 50mm

 

[Chuck]

Can you take and upload a couple of photos showing the cylinder and pipework? Also what happens to the copper pipe from the tundish after it disappears into the wall.

 

[Stigster]

If it's a trapped tundish and it terminates into a soil pipe, flushing the toilet could be pulling air in through the tundish as the water goes past.

Also, what Shaun said.