Bubbling Rads

[Lmdb]

We recently replaced our old baseboard water rads with new Runtal water rads. We've bled the rads a few times, but there are still several rads on the second floor that make a gurgling noise the entire time the heat is on. One on the main floor also makes the noise.

When bleeding the rads, we are getting some air, but not much, and the level of gurgling has remained pretty much the same.

Do we need to keep bleeding the rads until the air is out, or is there something else we need to look at.

Also, are all the ticks and clicks and banging common to all rads?

Thanks!
Lisa

 

[JohnD]

This is a UK website and our methods are different to yours

But, you can expect some initial trapped or dissolved air to move around and it needs bleeding out, after you have been working on the system. Having all rads on and hot will help the air to come out.

Also, if you have put fresh water in, it is usual over here to add a corrosion-preventing chemical (inhibitor) to the water when you refill, otherwise the steel and copper parts of your system will corrode where they are in contact with water. This corrosion releases hydrogen gas inside the radiators. It also produces black sludge (or brown rust, which is worse) and eventually causes blockages and leaks.

Over here the chemical costs about £15 ($30) a litre (which is a bit under two pints) and will suffice for 100 litres (20 gallons) of circulating water at a 1% solution and is about the right amount for most houses.

You will need to find out what chemicals are available locally, and the correct proportion to use.