Bleeding radiators... How do I?

[Dibble]

OK, where do I start - top or bottom of the house?

Heating on or off?

Radiators on or off?

Go, plumbing knowledge PHers, go!!

[simpo two]

Radiators on - I don't think the order is important as you're just bleeeding air from each one. Just turn the key until water comes out. Peasy

[john75]

Heating on

Air rises in water so start with the top of the house

Make sure you do not turn the keyy to much otherwise it will be messy

[Dibble]

Cheers.

2 minutes though. I ask you. This place is getting slower and slower for advice...

[danielgray]

bleed all the ones with air in, run your hand up and down them when they "should" be hot, if they are cold at the top then they have air in so bleed them, simple.

[Parrot of Doom]

Don't forget to add more water at the boiler once you're done.

[dave_s13]

On a similar note, my boiler needs topping up every now and then via the quick fill loop. That can't be normal? Where's the bloody water go? No obvioius leaks anywhere?

Soz fo the thread hijack but you kinda got yours answered and I couldn't be arsed sarting a new one

[Dibble]

Parrot of Doom said:

Don't forget to add more water at the boiler once you're done.

Done - thanks for the reminder.

[robinhood21]

dave_s13 said:

On a similar note, my boiler needs topping up every now and then via the quick fill loop. That can't be normal? Where's the bloody water go? No obvioius leaks anywhere? Soz fo the thread hijack but you kinda got yours answered and I couldn't be arsed sarting a new one

Amongst other things, water has oxygen in it. So when the water circulates it is bled out of the system via the automatic bleed valve within the boiler.

[bluespanner]

the school rads get hydrogen in them, cos they rust internally, so every so often a guy comes round and makes flames, which is great fun.

[dave_s13]

robinhood21 said:

dave_s13 said: On a similar note, my boiler needs topping up every now and then via the quick fill loop. That can't be normal? Where's the bloody water go? No obvioius leaks anywhere? Soz fo the thread hijack but you kinda got yours answered and I couldn't be arsed sarting a new one Amongst other things, water has oxygen in it. So when the water circulates it is bled out of the system via the automatic bleed valve within the boiler.

Oh yeah! I shoulda thought of that really. Cheers.

[ferg]

robinhood21 said:

dave_s13 said: On a similar note, my boiler needs topping up every now and then via the quick fill loop. That can't be normal? Where's the bloody water go? No obvioius leaks anywhere? Soz fo the thread hijack but you kinda got yours answered and I couldn't be arsed sarting a new one Amongst other things, water has oxygen in it. So when the water circulates it is bled out of the system via the automatic bleed valve within the boiler.

That's not strictly true. Driving oxygen out of water isn't that easy and certainly not all boilers have an auto air vent in them.

If you are losing pressure it is MOST likely that you have a leak....
Pipework under floors if a possibility, leaking heat exchangers in the boiler lose water that is instantly vapourised and ejected from the flue...

'Air' in radiators is most commonly hydrogen as mentioned above, although it can be drawn in on the suction side of the pump if you have a small leak there.

Central Heating water has no free oxygen to rust stuff and is virtually inert. The problem comes if a leak allows the topping up with fresh oxygenated water or in an open vented system 'Pumping over' can re-oxygenate.

By the way, vent downstairs first. This way there is less chance of the air moving upstairs once you have bled the upstairs. I always bleed with the pump running and if there is a lot of air in the pipework I turn off all the radiators and open one at a time, closing the previous one to clear the runs fully.

[scared but happy]

We have just had gas central heating installed today. It is utter compared to our old electric heating.
Do carry on...