Ariston Combi lack of pressure

[janandmuzz]

Hi,
All my upstairs rads were cold at the top so I bled them. (didnt turn boiler off as I didnt know you had to) Managed to get 2 hot up to top then couldnt figure why after a while the next one started sucking. Went out for 2 hours. Came back, 1 that had been hot all over was now half cold. Continued to try to bleed (with boiler on). Now almost nothing moved. Did some research on web. Pressure guage shows 0.3 Have found filler loop and attempted to top up but nothing seems to happen. Should the boiler be on when you open the loop ? Have tried on and off.
Help any one please.

 

[Gasguru]

Boiler should be off. There may be two valves on the filling link. Presurise to 1 Bar with the radiators COLD. Then check the pressure doesn't go above 2 Bar when the rads. are hot.

 

[janandmuzz]

Thanks for that, unfortunatly i had both taps (one at each end) open on the loop. Is that what you meant. Nothing seemed to change. Should the pressure go up instantly or does it take hours .

 

[Gasguru]

You should immediately hear the water running through the loop and pressure will start to rise (it will take a little time if there is plenty of air in the rads.)

What does the fillling loop look like? ie small black taps, screwdriver slot, large white taps

 

[janandmuzz]

Thanks again,
Cant hear or feel water moving. The loop is actually silver woven pipe and the tap heads are blue plastic squarish, about 1cm across. They are currently in towards the pipe. When I unscrew (opening I think) they come out about 1/2 cm. This takes about 3 1/2 turns.
System been running all night and pressure now at 0.4.
Forgot to add, when boiler is off pressure guage drops to nil (appears off) and when you open loop nothing changes.
Help