Hi, did I read this correctly when you say you have no heating up stairs.
If so can we take it there is hearing somewhere in the house, and as such
the system is working to this extent, if so check that pumps, timers, and
valves, whether they be electronic or manual are working, and most important
there should be a blow off valve or valves in the system to ensure you don't
end up like rocket man, hanging onto a boiler as you both are taken through the
roof or wall.
A perfectly working heating system will not put water up past a certain height,
unless conditions are met.
One tank in particular, is used as an expansion / overflow for an appliance
such as a wood stove or any other such stove to heat water, must be well above
the highest radiator, in order to keep pressure in the system, the pumps that curculate
water from your boiler or stove are not pressurised, they only add momentum, you need
the weight of the water in that expansion tank to force the water around, especially
around an up to the upper level of the house.
I think you are using what we call radiators, that are fed hot in one side and the coller
water then comes out the other and back to the boiler or stove for re heating.
If so, ther will be two valves on every radiator, one valve usually has a knob on it,
this is so the house owner can adjust the heat, close it for no heat, the valve at the opposite end of the radiators, is even more important, it must be almost closed, for it
it is not, this is to ensure the water remains under pressure and will infact rise up to the higher levells.
People also zone their rooms, or floors so they can for example turn off a complete
floor when the visitors are all gone back to where ever, no point in heating a complete
floor when no one is up there, smaller homes zone rooms, so what am saying is to look for valves that could be turned off, and thus no water or hear will ever get past that point.
I doubt that someone with an engineering degree would mess up too much, or indeed
live in the cold as a result.
The heating system might have more going or it than you think.
Also, if you are heating water for radiators or any other use with a stove or such
that can not for obvious reasons be controlled, then an open or vented system
is a must, you can not have a closed system because there is no way to control the output of an open fire stove or such device, gas can be turned off via a stat, so can oil
fuelled boilers, but not wood stoves or coal stoves, modern devices can damp them down, put less air into them and sorts, but that is not enough to safely run such a stove on a closed loop.
You also need copper or steel piping for about six foot from the outlet of the stove, this keeps the water from melting the other types, ive seen it happen.
Regards, john