Sealed system boiler Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[paulride]

does a boiler for a sealed system have to positioned above all the radiators?

[plumbbob]

No

[paulride]

[quote="plumbbob"]No[/quote]

I was told that if the boiler is to be fitted below any of the rads in the house it must be filled 'under pressure'?

Is this correct?

[Steve the gas]

A sealed system is under pressure approx 1.2 bar normally.

[plumbbob]

I am not quite sure what you are asking here. I don't understand "filled under pressure"? All sealed systems are pressure filled.

Where exactly the boiler is situated in relation to the radiator heights is immaterial. I would guess in domestic installations, the majority of boilers are below the height of the upstairs radiators.

The only consideration with pressure is the minimum required to fill the system. If we imagine the boiler in a basement of a house with heated attic rooms. Given that the highest radiator could be, lets say, 7 metres above the pressure gauge on the boiler and each metre head of water is about 0.1 bar, the gauge in the boiler would have to read 0.7 bar before the attic radiator would fill.

[DEEARR2]

Even if your heating system is conventional and not pressurised the height of the feed & expansion, usually located in the loft space, well above the system, will be sufficient to feed all radiators.