Boiler producing air / gas in CH

[Unklian]

Hi Again.

I'm having to bleed air out of one of my radiators on a weekly basis.

My boiler is not kettling. (It's an old Glowworm) About 30 years old.
I'm running a fully pumped sysem wth zone valves for DHW and CH.

I've heard that due to deposits in the boiler, bubbles of gas can be produced. Is there a cure for this or are the products just smoke & mirrors?

Touchwood, nothing seems to be leaking and the header tank level remains constant.

Also, When the TRV on the radiator is almost closing. ie, when the desired temperature is almost reached, minute bubbles of gas can be heard "crackling" through the tiny gap. Opening the TRV quickly results in a lump of air entering the radiator.

Bleed it, all OK for about a week, then annoying again.

Any suggestions please?

Cheers.

Ian.

 

[Burnerman]

Magnetite, the black sludge present in the vast majority of systems, produces its own gas - hydrogen - hence the need for constant bleeding.
The only sure way is to have the system flushed and inhibited.
You can do much to help yourself (see FAQ's) - it all depends on how much you want to get stuck in.
A magnaclean particle remover helps tremendously, too.
John

 

[Unklian]

The system is currently protected with Sentinel X100 (about 2 years ago)

What do you think to this suggestion.

Drain system.
Fit Magaclean.
Fill system with a cleaning chemical (Any suggestions which?)
Close all TRVs and lockshields.
Open 1 rad at a time.
Run heating until that radiator is red hot.
(Hopefully dislodging any magnetite).
Close that radiator......Open next radiator and repeat untill all radiators have been flushed.
Drain system, empty Magnaclean.
Re-fill with X100
Bleed etc.

 

[Burnerman]

There's nothing particularly wrong with that method...personally I like to take the rads off, get them into the garden and in with the hose pipe to get rid of most of the sludge....I then open the valves in turn and allow the water from the header tank to flush each pipe. At the same time, I'd replace any faulty rad valves with new drain down ones, before going for the Magnaclean and inhibitor.
It really depends on how dirty your system is, I guess.
John

 

[namsag]

Have you checked there is water in header tank and cold feed is not blocked . Also check air is not being sucked down open vent,,
Boiler off cup of water dip open vent into it, ask someone to turn heating on if water is sucked out the cup thats the start of an investigation why

 

[Unklian]

Have you checked there is water in header tank and cold feed id not blocked . Also check air is not being sucked down open vent,,
Boiler off cup of water dip open vent into it, ask someone to turn heating on if water is sucked out the cup thats the start of an investigation why

Water in header tank.
Vent over not blocked.
Cold feed not blocked.

Just checked all those whilst checking loft / pipe insulation during recent weather.

The air is not being sucked into the system via the ventover.
That was one of my early thoughts. I have easy access to where the fill and vent pipes leave the rest of the system. They are in the cylinder cupboard and are uniformly warm. From feeling the temperature of the pipes when the pump is on / off, CH or DHW demand, there is little movement of the hot / cold water.

The amount of air being produced is very small.
Opening the bleed screw, all air is expelled in a couple of seconds.
Not a huge problem at all really, it's more annoying when the TRV crackles with the tiny air bubbles.

It reminds me every morning that my CH system is not working properly.

I could continue the fortnightly bleed session but I'd rather everything was in good order.

Ian.