Central heating doesn't appear to be a closed system

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Hi there,

I have a query that has confused my limited knowledge of plumbing. I have moved into a new house where the radiators connected using copper microbore pipping. Each radiator has been connected separately to the main pipes running from the combi boiler in the loft. I needed to remove a radiator off the wall for replastering and as there appeared to be nowhere to drain the system, we disconnected a radiator and collected the water leaking out – this appeared to be predominantly from the radiator itself and looked like it had the rust additive in it – no water came out from the piping itself. Presumed this was fine, however later on when using the hot water tap in the kitchen, clear water started coming out of the piping where the radiator had been removed.

I can’t understand why this happens as I presumed that it would be a closed system, so failing to understand why it is affected by using the tap. I have since put the radiator back on, as 8mm stop ends I purchased failed to fit onto the microbore pipe ends. I wonder if it was caused by air getting into the system from the open pipes, and it emptied the remaining water in the system, but then this doesn't explain why the water that came out was clear and didn't have the addative in it.

So I’m wondering if anyone can help advise firstly why this is happening and secondly, how is the best way to go about removing radiators as I require these to eventually be removed in all the rooms.



Many thanks

 

[gas112]

so you never turned the valves off to the rad and wondered why water came out when the pump kicked in for HW

 

[adsada]

so you never turned the valves off to the rad and wondered why water came out when the pump kicked in for HW

I mean this is probably a daft question but are the HW and central heating not separate and separate pumps? I don't understand if it's a closed system why running the HW would pump HW into this system?

Where would the shut off valves be to the radiators, as I couldn't locate them

 

[gas112]

I mean this is probably a daft question but are the HW and central heating not separate and separate pumps? I don't understand if it's a closed system why running the HW would pump HW into this system?

Where would the shut off valves be to the radiators, as I couldn't locate them

on the actual radiator put a pic up of your rad

 

[adsada]

on the actual radiator put a pic up of your rad

 

[terryplumb]

You close both valves on the rad ,remove the rad after draining it, and fit blanking cap nuts to both valves.
No need to remove the valves from the pipework.

 

[gas112]

eh that is valves either side , got to be a windup post

 

[Deleted member 267285]

I mean this is probably a daft question but are the HW and central heating not separate and separate pumps? I don't understand if it's a closed system why running the HW would pump HW into this system?

Where would the shut off valves be to the radiators, as I couldn't locate them

It’s a combi boiler, so usually just the one pump. The heating and hot water remain separate circuits, so as not to drink heating water, but the boiler uses the heating water to heat the hot water, which circulates around a heat exchanger then a secondary heat exchanger (usually).

 

[kidgreen61]

Why would you drain the system to remove a rad?
Just turn valves off, and remove rad.

 

[adsada]

That's really helpful thanks all!