I moved into a property its a simple 2 up 2 down terraced house about 2 years ago.
over the past few weeks i have noticed something odd which i will do my best to explain so hear goes.
The property has a valiant combi boiler and gas fired central heating. the boiler is located downstairs in the kitchen. I have no hot water or cold water storage.
Last week i was running the shower which is just a mixer thing from the taps of the bath where you turn the lever.
when i got out the shower i heard the radiator/towel rail in the bathroom gurgle almost like there was air in the system. when i felt the towel rail it was cold which makes sense as the central heating was off, but when i felt the pipe leading to the towel rail this was hot!
following this i went downstairs to the boiler there were no taps running and the central heating was off but then for no apparent reason the boiler fired up and then after 2 seconds just turned off again.
Since this happened i have been keeping an eye on it and it seems that everytime the hot taps are run for a period time what i described above happens all over again.
Now im not a plumber but have looked into it and found that the hotwater system is completely seperate from the closed loop central heating so why does the radiator pipe in the bathroom get hot and why does the radiator gurgle if there seperate systems, also why does the boiler fire up on its own shortly after the taps are run (its almost like there is a backfeed or something).
Since I noticed this I have been keeping an eye on the pressure in the boiler for the heating system and this is constant at just over 1 bar.
Any advice on the cause or a solution is greatly appreciated.
Also not sure if this helps but the bathroom is directly above the kitchen Unfortunatly i dont know the route of the pipework. but i have 3 radiators downstairs, 2 upstairs plus the towel rail.