Newly registered on site !
Been struggling with this one for some time - no responses from 'other' plumbing forum !
Problem:
Sealed System CH loses pressure on cooling down.
Background:
Boiler is Gloworm 60FF with Gloworm Sealed System kit.
DHW cylinder is Heatrae Sadia MegaFlow - but this shouldn't matter ?
When non operational CH holds Water Pressure @ 1bar.
Expansion Vessel holds pressure. This is set at 1bar when cold and only static head pressure in CH circuit. EV does not exhibit water leakage from Schraeder valve.
No (obvious) air in system.
Symptoms:
When using CH pressure builds rapidly towards 3 bar and starts discharge trickle from PRV drain (there is no water loss from PRV when cold). Also I have not noticed sudden discharge (with the expected accompanying bang) from the PRV.
On cooling CH pressure has dropped to 0.2 bar (or less) and a lot of air has been admitted to system necessitating top up via filling loop. During this time the EV has NOT lost pressure at Schraeder valve and there is no noticeable increase in pressure monitored at the EV Schraeder valve.
Not sure what auto air vent is doing - boiler instructions say that auto air vent cap should be 'slackened off but not removed' (What is the auto air vent cap - the pics don't explain) and it says it should not be retightened.
The pressure loss DOES NOT occur when DHW only circuit is in use - I'm guessing that the expansion of the relatively small volume of water is tolerated ?
Any ideas and help would be greatly appreciated,
Regards,
Andy
Been struggling with this one for some time - no responses from 'other' plumbing forum !
Problem:
Sealed System CH loses pressure on cooling down.
Background:
Boiler is Gloworm 60FF with Gloworm Sealed System kit.
DHW cylinder is Heatrae Sadia MegaFlow - but this shouldn't matter ?
When non operational CH holds Water Pressure @ 1bar.
Expansion Vessel holds pressure. This is set at 1bar when cold and only static head pressure in CH circuit. EV does not exhibit water leakage from Schraeder valve.
No (obvious) air in system.
Symptoms:
When using CH pressure builds rapidly towards 3 bar and starts discharge trickle from PRV drain (there is no water loss from PRV when cold). Also I have not noticed sudden discharge (with the expected accompanying bang) from the PRV.
On cooling CH pressure has dropped to 0.2 bar (or less) and a lot of air has been admitted to system necessitating top up via filling loop. During this time the EV has NOT lost pressure at Schraeder valve and there is no noticeable increase in pressure monitored at the EV Schraeder valve.
Not sure what auto air vent is doing - boiler instructions say that auto air vent cap should be 'slackened off but not removed' (What is the auto air vent cap - the pics don't explain) and it says it should not be retightened.
The pressure loss DOES NOT occur when DHW only circuit is in use - I'm guessing that the expansion of the relatively small volume of water is tolerated ?
Any ideas and help would be greatly appreciated,
Regards,
Andy