3 out of 7 rads working with hot water

Check the pump is working . or its air in the pump check you have power to room stat

if there is no control of air movement between floors and you have it on cooling then any cold air will go down to the lower floor
or alternately if you have it set on heating all the hot air will rise to the upper floor
where is the system located (upstairs or down stairs ) and where is the thermostat located
to get control close any upstairs to down stairs doors or erect a heavy curtain across the stair well

lost pressure raise pressure up 2 bar and bleed the rads keep topping up untill all air has gone from rads do this with the pump off, turn all your rads back on and follow what in said .

is resurculating pump running ? cold rads maybe air loicked try bleeding off water at each rad.

Hi check power to stat , this must control valve to upstairs heating check valve is working , check rads for air upstairs

Make sure the air is bled from the upstairs rads.
[air = top of rad is cold & bottom hot]

If you need to balance the rads to maintain an even flow through all then :-
Turn off all rads [one valve fully open and the other closed] Get heat going and open each rad valve, in turn, about 1 or 2 turns. Start with upstairs. The position you need to get to is when the return pipe fron each rad is a few degrees below the flow pipe. Adjust each rad valve to get this effect a few times may be necessary

balance the rads.
upstair radiators turn all valves off,heat will then divert downstairs,open valves upstairs 4 turns on locksheilds and number 4 on trvs if u have any.
then if that does not work get a combi or powerflush.
if u cant afford then drain a little from rads,get x300 sludge remover from plumb shop and put in header tank(not hot water tank).
then fill system up and repeat balancing.

www.jollygreenplumbingmachine.co.uk

Problem is balancing & flow. Turn down the other rads until the inlet [flow] pipe is hot but the outlet [return] is luke warm. The rads have two valves - use the one which has a non-operation cap [just turns without doing anything]. when all the rads are the same temperature the system is said to be balanced and should be left like that using the other valves [with operating cap] to turn them on or off as required

is the pump running or is there an air lock near to the boiler check water tank in loft the smaller one to make sure you have water in the system

the problem there a relay stuck or thermostat bring on the pump & you can lower your high limit aquastat!! also the flow valves can bypass hot hot water risers time to put in a seperate water heater domestic coil are not energy efficient !!!! aquastat high limit set @ 180f deg low limit set @ 140f deg!!!
good luck!!! tim