Constant bleeding of radiators required

MiserlyMartin

Hi no amount of bleeding seems to stop the air in my system. It always effects the radiator nearest the pump and the radiator on the landing. The boiler and pump are in an airing cupboard upstairs. The rushing of water is worse if the hot water heating is turned on therefore the boiler is heating the hot water cylinder as well as the rads. If I bleed the radiators once I turn the heating back on the rushing and gurgling start straight away and if I turn it off again 2 mins later the radiators already need bleeding again!

I tried the slower pump speed, it seems to have made it better but air is still there! Its a vented traditional system.

Can anyone think what the problem is please?

EliteHeat

Hold an upturned cup or glass above the bleed valve next time you do this and then hold a lighter or a match to the glass / cup.

Let us know if it 'pops' or not. This will reveal whether it is hydrogen or normal air in the system.

DVardysShadow

MiserlyMartin wrote: »

... Can anyone think what the problem is please?

My immediate thought is corrosion. Elite Heat got there first, but he is being cryptic.

EliteHeat

DVardysShadow wrote: »

My immediate thought is corrosion. Elite Heat got there first, but he is being cryptic.

Aha, I'm going for maximum plausible deniability in the likely event that I'm talking !!!!!

bambibashercol

Maybe time for some sentinal in the system.

Wookey

If the volume of air is as great as you are making it out to be its more likely to be pump over or a leak. To check for pump over, watch your feed tank for the heating in your roofspace, the vent pipe that goes up over it and turns down into it will be venting water, this can draw air into the system when it occurs. To check for a leak, allow your system to go cold, once water is at its coolest make a mark on the side of the feed tank where the water level is, also tie up the ballcock so no water can enter the tank, check back after a few hours and see if the water level has dropped.

Elites test is spot on for identifying rusting occurring within the system, any sign of the "air" escaping thru the bleed valve either burning or going pop is a sure sign of decay, fresh water and air entering your system will induce rusting far more quickly as any rust inhibitor will be watered down significantly.

C_Mababejive

Is it a conventional system or a sealed/combi system? If the former,it could be a blocked cold feed.