Bathroom radiator needs bleeding every week

[MNW67]

I have a problem where the main bathroom radiator needs bleeding every week. The gas explodes with a little pop. It's a 35 year old open vent system and air/gas only collects in the main bathroom radiator. I paid a plumber to come and drain the system a bit and put in two bottles of F1. But he wouldn't do it. He made it clear he didn't want to disturb such an old system. The only drain point is in the garage. What would happen if I just put two bottles into the header tank without draining? Presumably it would eventually disperse through the system. Could it do any harm, though, with such a high concentration in the header tank?

 

[ChrisJP]

Duplicate post. Replied to in the other one.

 

[MNW67]

If there's no leak, then inhibitor put into the header tank will not disperse through the system because there is no flow from header tank into the rest of the system.
To get inhibitor into the system, you need to turn off the water supply to the header tank and drain off enough water to empty the header tank. Then add the inhibitor and turn the water to the header tank back on to refill the system and draw the inhibitor into the system.
Alternatively, close both valves on a radiator, drain it out, and add the inhibitor to the radiator by removing the bleed valve or the plug at the other end and using a screw-in tube and funnel (available via a search online)

That may be beyond me at the moment!

I was hoping it might slowly spread through the system as the water expands and contracts and mixes in the header tank.

 

[MNW67]

Do you have a Magnaclean or similar? That's by far the best way to add inhibitor, and to sample the water for testing. If not, worth considering getting one.

No, I'm afraid not. I will be getting one when I change the boiler. I'm not totally clear what put the plumber off from doing the job. But he said I should just pour the inhibitor into the header tank and it would work its way around.

 

[Jurassicspark]

Which boiler is it?

 

[MNW67]

Which boiler is it?

Baxi FS circa 1990

 

[MNW67]

There seems to be a drain valve on the floor next to the boiler in the garage. It looks like this, but it's horizontal. I'm not sure I'm up to it physically at the moment because it's in a very awkward spot. But is it simply a matter of attaching a hose and turning the knob?