No.1 U.K. Professional Trade Forum, Plumbing, Gas, Electric, Tiling and Joinery Forum

Immaculate 1930s house, lifting flooring not an option.
Open vent, gravity hot water.
Seeking to confirm suspicion of single pipe distribution to rads.
Observation. Turning heat on with rads half full and cold, venting air results in both pipes to rad immediately becoming hot.
Advice on any other test to confirm or disprove, appreciated.

TBH, i had one the same once,
took 8 hours bleeding the damn thing due to air locks and 'boiling' over didnt even work!
i walked away from any others lol.
Nice to see you again Joni.
Try getting a thermal camera to confirm under floor heat source is probably what i would do if the budget is there, then it could also be a mixed system!
good luck

Thanks for response and mention of "boiling".
Doesn't happen with gravity DHW acting as heat sink but high possibility should I interrupt with MV.
Will give hard word about lifting flooring for a proper diagnoses. Chrystal Ball insight beyond my talents.