Boiler losing pressure, cant track where water going!!

[micol1873]

Hi the boiler is losing pressure, about 1.5 every 8 hours. Checked expansion vessel and flow regulater which are all fine. all radiators are topped up and no air in them. Topped up pressure to 1.5 bar last last and closed flow and return valves on boiler to establish if it is boiler or pipework, checked this morning and pressure still 1.5 bar. Have chased all pipes as none are hidden and all ok cant see any leaks.....anyone any idea why pressure is dropping when flow/return valves open.......all signs point to a leak and at this rate it should be noticable but its not!!

 

[lightning]

Have you checked all radiator valves,check prv pipe is not dripping

 

[micol1873]

yes all rad valves are fine no water from prv or drainoff ,,

 

[xr4x4]

If all else fails, try some leak sealer?

 

[lightning]

What boiler do you have?? could be pin hole leak in heat exchanger ,water going done condensate pipe

 

[xr4x4]

Topped up pressure to 1.5 bar last last and closed flow and return valves on boiler to establish if it is boiler or pipework, checked this morning and pressure still 1.5 bar.

 

[fine tune]

if the pressure dropped when you opened the valves the leak must be on the heating circuit , take the rad valve tops off and check for leaks from the packing gland. thermostatic rad valves are on and off all the time and are notorious for this . press the pin down a few times to check for leaks . top pressure back up before checking

 

[Googlyhead]

if the pressure dropped when you opened the valves the leak must be on the heating circuit

Or in the cylinder coil itself (assuming a HW cylinder is present)
Any way of turning off entirely either HW or Rads circuit? If nothing else; remove all tmv tops (so closed) and close the valves the other side, just to eliminate any radiator as being a problem.

 

[bengasman]

More info about the system is essential.