Sprawling, aged heating systems often suffer from “pumping over” into the header tanks, this can happen due to system changes caused by perhaps new radiators or heat emitters and / or debris blockages within the system.
The pumping over adds oxygen back into the system, the hot water vapour splashing off the tank can also cause damage to the building.
This can be eliminated by pressurising the system.
This can be achieved with some minor pipework modifications and installation of suitably sized pressure vessels.
Low cost versions of this modification can use manual fill systems.
However manually operated systems are subject to peoples memory, work load and absence.
Most systems lose water volume, especially older systems, with the associated system pressure loss.
Low water pressure allows air to be drawn into the system which causes heating problems and will eventually cause corrosion, this leads to sludge which inevitably ends up in the boilers and eventual failure.
Automatic fill systems can be achieved with a suitably sized pressurisation unit.
Please don’t let this lead to abandoning regular visual inspections of plant and equipment.
You may also see a dosing pot below the pressurisation unit. Systems should be dosed, the more difficult it is to dose a system, the less likely it will be done.
The great thing about not dosing a system is that it saves you money and is normally a problem for someone else.