Central Heating System Water Volume

[Shudavleftit]

Hi,
I am trying to find the volume of water in my central heating system with a view to making sure the proper amount of inhibitor is in it.

The system is as follows ...
2300 ft2 four bedroom house with underfloor heating (1228m of 10mm i.d. pipe)
1 x small single radiator
1 x small double radiator
1 x large towel rail
1 x medium towel rail
Boiler (24.8 liters)
Systemlink
Pipework including manifolds

I have calculated a total of 175 liters of water. What do people think of that, does it sound close to what they would expect. I have not added any volume for the 12 liter expansion vessel as I take it that this has no water in it when the system is cold. Is that correct ?

 

[Burnerman]

Overdosing with inhibitor isn't a problem, so always err on that side!
John

 

[Nige F]

err, that`s a good answer

 

[Shudavleftit]

That seems to be common opinion alright. However I have been also told that overdosing with inhibitor can lead to 'foaming' of the central heating water ?

 

[D_Hailsham]

That seems to be common opinion alright. However I have been also told that overdosing with inhibitor can lead to 'foaming' of the central heating water ?

Never heard that one! But you would probably have to overdose by a significant amount before that happens. The normal dosing is 1% of system volume. Putting in, say 3% or even 5% unlikely to have any foaming effect.

Some plumbers bung in a can every time they do any work to a system - just in case the inhibitor level is too low.

I would add 2 cans of Sentinel X100. If you are in a hard water area, also add 2 cans of X200. You can always get a test kit and check the water.

Your boiler has a large water content. Which boiler do you have?

 

[Shudavleftit]

My boiler is a Sime Rondo 6.

 

[D_Hailsham]

My boiler is a Sime Rondo 6.

Ah! A big oil fired beast. No wonder it has such a large water content.

 

[Shudavleftit]

Our house was a 'self-build' that started in 2003. It is a bungalow but we fitted Velux windows in the roof and sheeted out the upstairs to leave it ready for an attic conversion (650 feet2).

The thinking by the plumber at that time was to put in a boiler that would be capable of also supplying central heating up there if ever needed so that might explain things if the boiler is oversized for the job it is being asked to do right now ?

Anyway thanks for your help. Sounds like super accurate measurement of the system volume is not that critical. I already have purchased a Fernox water test kit. My thinking was to test the water as it is now and after getting the results decide on appropriate action i.e. flushing/inhibitor etc.

 

[Burnerman]

The foaming is just a very slight effervescence that has no effect on the system at all.....if its there when you bleed a rad then you know there is inhibitor in!
I like the Fernox F1 concentrate thats injected into a rad through the bleed valve hole.
John