Adding Inhibitor

David_Aston

Forgive if wrong forum.
Our plumber, a friend, has just finished replacing and bringing back into use our central heating system. That is, all of the radiators.
I chose some Stelrad Radical radiators for downstairs, and even I can see that they are a bit of a pig to fit. PlumbNation rather slowish to sort out faulty bits, so finally after three months, the inhibitor went in, and all rads plumbed into the system.
Said plumber is off on his hols next week, and we told him we are quite happy to experiment with trv settings, and to try and get all air out of the system.
Finally, my question. We are getting loads of air, and in the process, water out of the system. Does anyone know if at some point, more inhibitor may need to be added, as original gets thinned down? And also, how I would add it without overfilling the header tank?
Cheers Guys

Le_Kirk

If you are losing water as well as air, you are not turning the bleed valves off quick enough OR are you trying to bleed with the system running? Unless you are bleeding out lots of water you shouldn't thin out the inhibitor too much. Don't forget to add water after you have bled.

FreeBear

David_Aston wrote: »

We are getting loads of air, and in the process, water out of the system. Does anyone know if at some point, more inhibitor may need to be added, as original gets thinned down?

When bleeding a radiator, you should only get a very small quantity of water coming out - More than an eggcup full, and you are making a right mess.

The small amounts of water that is being replaced would be insufficient to dilute the inhibitor beyond the point of effectiveness. I wouldn't worry about it unless you are draining gallons out of the system.

missile

If you bleed properly, you will get air out without "lots of water".

If your plumber added the correct concentration of inhibitor it is most unlikely that you will need to add more.

If he did not, you simply turn off the feed to the header tank, drain down sufficient water, replace with inhibitor, then turn on the feed.

Gloomendoom

As above, you shouldn't be losing any water when you bleed the system, just air.

What I did to add inhibitor before I fitted an in-line crud filter was to drain enough water out of the system to empty the header tank and then some (turn off the supply first or wire up the ballcock). Then I added the inhibitor to the header tank and turn on the water.

If there is a filter fitted to the system, it may have the facility to add it via that rather than draining down the entire header tank.

David_Aston

Thanks for your comments guys.
I have always assumed that the header tank automatically replaces any water which is bled out, and is then turned off by the ballcock, as most of you guys have said. Three of the new rads have a plastic rotating bleed valve, well proud of the rad, which is great really, as you can place a dish underneath and direct the water/air into it. I reckon we have maybe drained a pint from the system, up to now.
We do have a Magnaclean fitted, and I think I can also bleed that.
I have also thought that the pump had to be running to bleed the rads. Perhaps this is not the case?
Thanks again, anyway.

missile

It is best to:
turn heating on
wait until up to temp
turn heating off
bleed rads
repeat after a week

See here > https://www.uswitch.com/energy-saving/guides/how-to-bleed-a-radiator/

Gloomendoom

David_Aston wrote: »

I have also thought that the pump had to be running to bleed the rads. Perhaps this is not the case?
Thanks again, anyway.

No, bleed with the heating off. Close the bleed valves as soon as water starts to spray out.

Having said that, a pint is nothing really when you consider the capacity of the whole heating system.