Adding a Radiator

[dantimp]

I plan to add a extra radiator to my heating system, I have bought the radiator however it states it cannot be used for a "direct central heating system" because you cannot put a corrosion inhibitor in it.
Can you tell me what a direct central heating system is?

My system is quite an old Baxi boiler and I cannot just have the water on on its own. and I have a small tank in the loft above the main tank which as far as I am aware is for the heating system (If this is any help.)

If mine is a direct central heating system, can I use the radiator anyway and the manufacturer is covering themselves or would it corrode easily without the inhibitor?

 

[TicklyT]

If you have a seperate F&E tank in the loft your system should be indirect. From the sound of it the the hot water is from gravity circulation rather than pumped, so is uncontrolled, or supposedly self-regulating, running whenever the boiler is on.

Direct systems are usually for hot water only. They don't have a seperate F&E tank, and circulate the domestic hot water directly through the boiler, so any inhibitor etc. would end up in your bathtub!

Indirect systems have a seperate water supply to feed the radiators and a heat exchanger inside the hot water cylinder. This is basically a closed (but vented!) loop, so any additives should circulate indefinitely - barring leaks!

 

[dantimp]

Does that mean then when I drain the system this smaller tank should also empty?

And then I put the inhibitor in into the small tank and the inhibitor will go into the system when I turn the water back on to for it to circulate and fill up the system.

As you say then you think mine is an indirect system because I cannot have the system on hot water only? because I need to turn the thermostat right down in the summer so that the rads dont come on!

 

[dantimp]

Had this on another post too and someone told me to check on the water cylinder for a label.

So had a look on the cylinder and there was a label at the back, and it says (Indirect Cylinder).

Will make a start on it later then!

Thanks for your assistance.