Cold radiators - no bleed valves...?

[vibe]

Hi everyone
I live in a flat with a Saunier Duval Thelia 23 gas combination boiler. Im certain I have air trapped in the system as the boiler makes a lot of hissing noises and most of the radiators are cold at the top. My problem is I cant seem to find any bleed valves on the radiators - I know where they should be located, but they just arent there. All I can find is a drain valve located at the bottom inlet pipe of one of the radiators - however opening this does nothing - no air or water comes out. Any ideas? Im desperate as its bloody cold! Thanks in advance

 

[Slugbabydotcom]

They have started hiding the vents now! They are there! They have to be! just look a little harder.

 

[ChrisR]

Feel over the back, top left corner, for a bump, which is a cap covering the vent. Now you'll see the ones on the rear panels?

 

[vibe]

Ahhh! Brilliant, thanks guys. No caps, but flush with the back side of the radiator. Loads of air coming out now - its a strangely satisfying experience

 

[vibe]

One more thing... plenty of air has come out of each radiator, but no water. The escaping air just fizzles out. Is this normal? I was under the impression that as soon as water started trickling out I should tighten the valve again, but it hasnt happened (obviously I tightened the valves again anyway). Does this mean there is still water trapped in the system? Cheers

 

[kevplumb]

re pressurise the system

 

[vibe]

nice one, thanks

Still managed to break my heater though. I pressurised it in increments to avoid having to drain it and suddenly the in-pipe stopped working. Think the screwdriver valve must have broken. Also the boiler has started leaking a bit - not heavily, just a drip every 10 seconds or so. And no I cant start it up

Have had to call an engineer. Still, my fault for not having it serviced for the last 3 years I guess

 

[weareleeds]

Try to find a saunier duval that doesn't leak they are made of plastic & that reversing valve is a buggar to change