Hello,
I would be grateful for some better minds to help me with my overflowing Cold Water tank.
I have an old fashioned traditional vented system with a main cold water tank and separate smaller header tank for the heating. They are both in the loft sitting on the floor with their bases at the same height.
This morning I noticed the cold water tank was overflowing. When I got to the tank it was warm and I could see the thermal plumes of hot water coming back up the HWC supply. However, the problem persists when the boiler is switched off.
If I close the HWC supply on the cold water tank then a dribble of water eventually appears out of the hot water vent once the loop has filled up.
My thinking so far is that, with the 2 tanks are at the same height, there can't be a pressure difference to push water through a split in the cylinder coil. Therefore, the leak into the hot circuit must be coming from mains water pressure somewhere.
The only places I can think of that mains pressure and the HWC are in contact are the Kitchen mixer and an upstairs venturi shower. The downstairs shower is gravity fed mixer. Downstairs bathroom taps are separate and upstairs bathroom sink mixer is gravity fed.
Isolating the kitchen mixer makes no difference. The venturi shower is fitted with check valves in both hot and cold supplies so shouldn't be the problem and isolating the cold supply to it makes no difference anyway.
The only thing that makes it stop is to turn off the main stopcock.
What am I missing? This has me stumped. I can't think where else water can be getting into the hot circuit.
I will be very grateful when somebody points out my error or what I have missed!
Thanks very much.
Mark
I would be grateful for some better minds to help me with my overflowing Cold Water tank.
I have an old fashioned traditional vented system with a main cold water tank and separate smaller header tank for the heating. They are both in the loft sitting on the floor with their bases at the same height.
This morning I noticed the cold water tank was overflowing. When I got to the tank it was warm and I could see the thermal plumes of hot water coming back up the HWC supply. However, the problem persists when the boiler is switched off.
If I close the HWC supply on the cold water tank then a dribble of water eventually appears out of the hot water vent once the loop has filled up.
My thinking so far is that, with the 2 tanks are at the same height, there can't be a pressure difference to push water through a split in the cylinder coil. Therefore, the leak into the hot circuit must be coming from mains water pressure somewhere.
The only places I can think of that mains pressure and the HWC are in contact are the Kitchen mixer and an upstairs venturi shower. The downstairs shower is gravity fed mixer. Downstairs bathroom taps are separate and upstairs bathroom sink mixer is gravity fed.
Isolating the kitchen mixer makes no difference. The venturi shower is fitted with check valves in both hot and cold supplies so shouldn't be the problem and isolating the cold supply to it makes no difference anyway.
The only thing that makes it stop is to turn off the main stopcock.
What am I missing? This has me stumped. I can't think where else water can be getting into the hot circuit.
I will be very grateful when somebody points out my error or what I have missed!
Thanks very much.
Mark
