Bleeding radiators.

[Jo]

A radiator needs bleeding and I have been given conflicting advise[8-)] one plumber says if I bleed it when the system is running I will just draw more air in, and another says if I don't bleed it when the system is on there will not be enough pressure to force all the air out[blink] who is right or does it matter???

[andyh4]

I think you need to find yourself 2 new plumbers, although the second is perhaps more nearly to be right.

You sould be able to top the system up with water somewhere - probably near the boiler.  Get someone to crack this valve as you bleed the radiator.  Once bled ensure that the whole system is operating (as in working) within it operational pressure range.  If not top up or crack the drain valve.

 

[TefkaC]

Hello Jo,

Shut the pump off,  let the system settle and then bleed the rad's from the highest in the system to lowest.... Hope this helps.

Regards Charlie.

[pitway]

As said, you need to turn the pump off or you could suck in air rather

than expel it, there is normally a pressure gauge on or near the boiler

and a tap connected to the mains water supply to allow you to refill the

system, make sure you have plenty of pressure in the system then crack

open the bleed valve on the offending radiator(s) until you get water

coming out (this water will probably be quite black and will stain your

wall or floor so have a bit of rag to catch any water expelled) it's not

a difficult job as long as you know where the refill tap is, I find I

have to do this a couple of times a season as the towel rail in the

bathroom seems to collect the air over time hope this make sense.

[Jo]

Have found the tap to feed the system[:)] there is a pressure gauge near it, but I have never seen it move so I suspect it's broken[:(]which makes it a bit of a guessing game[blink] I have 'topped up' the system before, and any excess comes out of the overflow. Am I correct in thinking that topping up is also best done when the system is off? Many thanks for all the help[:)]

[TefkaC]

Hello Jo, not knowing the system this is a bit of a guessing game but as you have topped up previously and as you say there is an overflow I would suggest you fill to the overflow with the system shut down, any excess will overspill when the system is heated through.. You need to check/change the pressure gauge....

Best of luck.

Charlie.

[Jo]

Many thanks Charlie, the gentleman who used to help me out with the system and knew it quite well, a retired heating engineer, is no longer with us,[:(] he said it was a 'closed' system and told me how to top it up,[geek] it was also he who told me he thought the pressure gauge needed replacing. Now we are out here permanently I have asked a plumber to come along in the summer, drain and clean it and replace the gauge so I should have a better idea then[blink] It was just with this very cold weather I wanted to try and get things working as well as poss!!

[BIG MAC]

Better to have the system off for the simple reason - if you vent a lot of air out the boiler may shut down due to pressure loss...not air ingress.

The weight of the water above you should in theory push the air out when venting 'downstairs' while upstairs you may need to 'top up' the system from time to time to raise the level of water..particularly if the boiler is below the level of the rads.

Once you have bled all your rads - recharge the system via the filling loop to the level proscribed by the boiler manufacturer (Probably 1 bar or thereabouts)

[Jo]

[I]Many thanks for that Big Mac.